MutT homolog 2; MutT Homolog 2 (MTH2; EC 3.6.1.9), also known as NUDIX (nucleoside diphosphate-linked moiety X)) motif 15/Nudt15, may catalyze the hydrolysis of nucleoside diphosphates, triphosphates including dGTP, dTTP, dCTP, their oxidized forms like 8-oxo-dGTP, and prodrug thiopurine derivatives 6-thio-dGTP and 6-thio-GTP. MTH2 may also play a role in DNA synthesis and cell cycle progression by stabilizing PCNA. Members of the NUDIX hydrolase superfamily catalyze the hydrolysis of NUcleoside DIphosphates linked to other moieties, X. Enzymes belonging to this superfamily require a divalent cation, such as Mg2+ or Mn2+, for their activity and contain a highly conserved 23-residue NUDIX motif (GX5EX7REUXEEXGU, where U = I, L or V), which functions as a metal binding and catalytic site. Substrates of NUDIX hydrolases include intact and oxidatively damaged nucleoside triphosphates, dinucleoside polyphosphates, nucleotide-sugars and dinucleotide enzymes. These substrates are metabolites or cell signaling molecules that require regulation during different stages of the cell cycle or during periods of stress. In general, the role of the NUDIX hydrolase is to sanitize the nucleotide pools and to maintain cell viability, thereby serving as surveillance _ "house-cleaning" enzymes. Substrate specificity is used to define families within the superfamily. Differences in substrate specificity are determined by the N-terminal extension or by residues in variable loop regions. Mechanistically, substrate hydrolysis occurs by a nucleophilic substitution reaction, with variation in the numbers and roles of divalent cations required.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 12324137   8 PRVAVVVFILNG-NSILLGRRRSSIGNSTFALPGGHLEFGESFEECAAREVMEETGLKIEKMKLLTVTNNVFKEAptPSH 86
Cdd:cd04678   1 PRVGVGVIVLNDdGKVLLGRRKGSHGAGTWALPGGHLEFGESFEECAAREVLEETGLEIRNVRFLTVTNDVFEEE--GKH 78

                        90       100       110       120       130
                ....*....|....*....|....*....|....*....|....*....|
gi 12324137  87 YVSVSIRAVLVDPSQEpKNMEPEKCEGWDWYDWENLP--KPLFWPLEKLF 134
Cdd:cd04678  79 YVTIFVLAEVDDGEPE-ENMEPDKCEGWEWFSWDELPplRPLFLPLANLL 127

NUDIX domain;

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 12324137     8 PRVAVVVFILNGN-SILLGRRRSSIGNSTFALPGGHLEFGESFEECAAREVMEETGLKIEKMKLLTVTNNVFKEAP--TP 84
Cdd:pfam00293   2 RRVAVGVVLLNEKgRVLLVRRSKKPFPGWWSLPGGKVEPGETPEEAARRELEEETGLEPELLELLGSLHYLAPFDGrfPD 81

                          90       100       110       120
                  ....*....|....*....|....*....|....*....|....*
gi 12324137    85 SHYVSVsirAVLVDPSQEPKNMEPEKCEGWDWYDWENLPKPLFWP 129
Cdd:pfam00293  82 EHEILY---VFLAEVEGELEPDPDGEVEEVRWVPLEELLLLKLAP 123

MutT homolog 2; MutT Homolog 2 (MTH2; EC 3.6.1.9), also known as NUDIX (nucleoside diphosphate-linked moiety X)) motif 15/Nudt15, may catalyze the hydrolysis of nucleoside diphosphates, triphosphates including dGTP, dTTP, dCTP, their oxidized forms like 8-oxo-dGTP, and prodrug thiopurine derivatives 6-thio-dGTP and 6-thio-GTP. MTH2 may also play a role in DNA synthesis and cell cycle progression by stabilizing PCNA. Members of the NUDIX hydrolase superfamily catalyze the hydrolysis of NUcleoside DIphosphates linked to other moieties, X. Enzymes belonging to this superfamily require a divalent cation, such as Mg2+ or Mn2+, for their activity and contain a highly conserved 23-residue NUDIX motif (GX5EX7REUXEEXGU, where U = I, L or V), which functions as a metal binding and catalytic site. Substrates of NUDIX hydrolases include intact and oxidatively damaged nucleoside triphosphates, dinucleoside polyphosphates, nucleotide-sugars and dinucleotide enzymes. These substrates are metabolites or cell signaling molecules that require regulation during different stages of the cell cycle or during periods of stress. In general, the role of the NUDIX hydrolase is to sanitize the nucleotide pools and to maintain cell viability, thereby serving as surveillance _ "house-cleaning" enzymes. Substrate specificity is used to define families within the superfamily. Differences in substrate specificity are determined by the N-terminal extension or by residues in variable loop regions. Mechanistically, substrate hydrolysis occurs by a nucleophilic substitution reaction, with variation in the numbers and roles of divalent cations required.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 12324137   8 PRVAVVVFILNG-NSILLGRRRSSIGNSTFALPGGHLEFGESFEECAAREVMEETGLKIEKMKLLTVTNNVFKEAptPSH 86
Cdd:cd04678   1 PRVGVGVIVLNDdGKVLLGRRKGSHGAGTWALPGGHLEFGESFEECAAREVLEETGLEIRNVRFLTVTNDVFEEE--GKH 78

                        90       100       110       120       130
                ....*....|....*....|....*....|....*....|....*....|
gi 12324137  87 YVSVSIRAVLVDPSQEpKNMEPEKCEGWDWYDWENLP--KPLFWPLEKLF 134
Cdd:cd04678  79 YVTIFVLAEVDDGEPE-ENMEPDKCEGWEWFSWDELPplRPLFLPLANLL 127

ADP-ribose pyrophosphatase YjhB, NUDIX family [Nucleotide transport and metabolism];

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 12324137   7 IPRVAVVVFILN-GNSILLGRRRSSIGNSTFALPGGHLEFGESFEECAAREVMEETGLKIEKMKLLTVTnnvfkEAPTPS 85
Cdd:COG1051   4 VPKVAVDAVIFRkDGRVLLVRRADEPGKGLWALPGGKVEPGETPEEAALRELREETGLEVEVLELLGVF-----DHPDRG 78

                        90       100       110       120
                ....*....|....*....|....*....|....*....|....
gi 12324137  86 HYVSVSIRAVLVDPSQEPknmePEKCEGWDWYDWENLPKPLFWP 129
Cdd:COG1051  79 HVVSVAFLAEVLSGEPRA----DDEIDEARWFPLDELPELAFTP 118

NUDIX hydrolase superfamily; NUDIX hydrolase is a superfamily of enzymes found in all three kingdoms of life, and it catalyzes the hydrolysis of NUcleoside DIphosphates linked to other moieties, X. Enzymes belonging to this superfamily require a divalent cation, such as Mg2+ or Mn2+ for their activity. Members of this family are recognized by a highly conserved 23-residue NUDIX motif (GX5EX7REUXEEXGU, where U = I, L or V), which forms a structural motif that functions as a metal binding and catalytic site. Substrates of NUDIX hydrolase include intact and oxidatively damaged nucleoside triphosphates, dinucleoside polyphosphates, nucleotide-sugars and dinucleotide enzymes. These substrates are metabolites or cell signaling molecules that require regulation during different stages of the cell cycle or during periods of stress. In general, the role of the NUDIX hydrolase is to sanitize the nucleotide pools and to maintain cell viability, thereby serving as surveillance and "house-cleaning" enzymes. Substrate specificity is used to define child families within the superfamily. Differences in substrate specificity are determined by the N-terminal extension or by residues in variable loop regions. Mechanistically, substrate hydrolysis occurs by a nucleophilic substitution reaction, with variation in the numbers and roles of divalent cations required. This superfamily consists of at least nine families: IPP (isopentenyl diphosphate) isomerase, ADP ribose pyrophosphatase, mutT pyrophosphohydrolase, coenzyme-A pyrophosphatase, MTH1-7,8-dihydro-8-oxoguanine-triphosphatase, diadenosine tetraphosphate hydrolase, NADH pyrophosphatase, GDP-mannose hydrolase and the c-terminal portion of the mutY adenine glycosylase.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 12324137  10 VAVVVFILNG-NSILLGRRRSSIGNSTFALPGGHLEFGESFEECAAREVMEETGLKIEKMKLLTvtnnVFKEAPTPSHYV 88
Cdd:cd02883   1 VAVGAVVFDDeGRVLLVRRSDGPGPGGWELPGGGVEPGETPEEAAVREVREETGLDVEVLRLLG----VYEFPDPDEGRH 76

                        90       100       110
                ....*....|....*....|....*....|
gi 12324137  89 SVSIRAVLVDPSQEPKNMEPEKCEGWDWYD 118
Cdd:cd02883  77 VVVLVFLARVVGGEPPPLDDEEISEVRWVP 106

ADP-ribose pyrophosphatase; ADP-ribose pyrophosphatase (ADPRase; EC 3.6.1.13) catalyzes the hydrolysis of ADP-ribose to AMP and ribose-5-P. Like other members of the NUDIX hydrolase superfamily of enzymes, it is thought to require a divalent cation, such as Mg2+, for its activity. It also contains a 23-residue NUDIX motif (GX5EX7REUXEEXGU, where U = I, L or V) which functions as a metal binding site/catalytic site. In addition to the NUDIX motif, there are additional conserved amino acid residues, distal from the signature sequence, that correlate with substrate specificity. In humans, there are four distinct ADPRase activities, three putative cytosolic (ADPRase-I, -II, and -Mn) and a single mitochondrial enzyme (ADPRase-m). ADPRase-m is also known as NUDT9. It can be distinugished from the cytosolic ADPRase by a N-terminal target sequence unique to mitochondrial ADPRase. NUDT9 functions as a monomer.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 12324137   9 RVAVVVFILNGNSILLGRRRSSIGNSTFALPGGHLEFGESFEECAAREVMEETGLKIEKMKLLTVTNNVFKEA--PTPSH 86
Cdd:cd04673   1 IVAVGAVVFRDGRVLLVRRGNPPDAGLWSFPGGKVELGETLEDAALRELREETGLEAEVVGLLTVVDVIERDEagRVRFH 80

                        90
                ....*....|....*...
gi 12324137  87 YVSVSIRAvlVDPSQEPK 104
Cdd:cd04673  81 YVILDFLA--EWVSGEPV 96

uncharacterized NUDIX hydrolase subfamily; NUDIX hydrolase is a superfamily of enzymes found in all three kingdoms of life, and it catalyzes the hydrolysis of NUcleoside DIphosphates linked to other moieties, X. Enzymes belonging to this superfamily require a divalent cation, such as Mg2+ or Mn2+ for their activity. Members of this family are recognized by a highly conserved 23-residue NUDIX motif (GX5EX7REUXEEXGU, where U = I, L or V), which forms a structural motif that functions as a metal binding and catalytic site. Substrates of NUDIX hydrolase include intact and oxidatively damaged nucleoside triphosphates, dinucleoside polyphosphates, nucleotide-sugars and dinucleotide enzymes. These substrates are metabolites or cell signaling molecules that require regulation during different stages of the cell cycle or during periods of stress. In general, the role of the NUDIX hydrolase is to sanitize the nucleotide pools and to maintain cell viability, thereby serving as surveillance and "house-cleaning" enzymes. Substrate specificity is used to define child families within the superfamily. Differences in substrate specificity are determined by the N-terminal extension or by residues in variable loop regions. Mechanistically, substrate hydrolysis occurs by a nucleophilic substitution reaction, with variation in the numbers and roles of divalent cations required. This superfamily consists of at least nine families: IPP (isopentenyl diphosphate) isomerase, ADP ribose pyrophosphatase, mutT pyrophosphohydrolase, coenzyme-A pyrophosphatase, MTH1-7,8-dihydro-8-oxoguanine-triphosphatase, diadenosine tetraphosphate hydrolase, NADH pyrophosphatase, GDP-mannose hydrolase and the c-terminal portion of the mutY adenine glycosylase.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 12324137  10 VAVVVFILNG-NSILLGRRRSsigNSTFALPGGHLEFGESFEECAAREVMEETGLKIEKMKLLTV 73
Cdd:cd04677  13 VGAAVIILNEqGRILLQKRTD---TGDWGLPGGAMELGESLEETARREVFEETGLTVEELELLGV 74

uncharacterized NUDIX hydrolase subfamily; NUDIX hydrolase is a superfamily of enzymes found in all three kingdoms of life, and it catalyzes the hydrolysis of NUcleoside DIphosphates linked to other moieties, X. Enzymes belonging to this superfamily require a divalent cation, such as Mg2+ or Mn2+ for their activity. Members of this family are recognized by a highly conserved 23-residue NUDIX motif (GX5EX7REUXEEXGU, where U = I, L or V), which forms a structural motif that functions as a metal binding and catalytic site. Substrates of NUDIX hydrolase include intact and oxidatively damaged nucleoside triphosphates, dinucleoside polyphosphates, nucleotide-sugars and dinucleotide enzymes. These substrates are metabolites or cell signaling molecules that require regulation during different stages of the cell cycle or during periods of stress. In general, the role of the NUDIX hydrolase is to sanitize the nucleotide pools and to maintain cell viability, thereby serving as surveillance and "house-cleaning" enzymes. Substrate specificity is used to define child families within the superfamily. Differences in substrate specificity are determined by the N-terminal extension or by residues in variable loop regions. Mechanistically, substrate hydrolysis occurs by a nucleophilic substitution reaction, with variation in the numbers and roles of divalent cations required. This superfamily consists of at least nine families: IPP (isopentenyl diphosphate) isomerase, ADP ribose pyrophosphatase, mutT pyrophosphohydrolase, coenzyme-A pyrophosphatase, MTH1-7,8-dihydro-8-oxoguanine-triphosphatase, diadenosine tetraphosphate hydrolase, NADH pyrophosphatase, GDP-mannose hydrolase and the c-terminal portion of the mutY adenine glycosylase.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 12324137   9 RVAVVvfILNGNSILLGRrrsSIGNSTFALPGGHLEFGESFEECAAREVMEETGLKIEKMKLLTVTNNVFKEAPTPSHYV 88
Cdd:cd04688   4 RVAAI--IIRDGKVLLAR---GEDDDYYRLPGGRVEFGETSEDALVREFKEELGVEVEVVRLLFVVENFFTYDGKPFHEI 78

                        90       100       110       120
                ....*....|....*....|....*....|....*....|....*
gi 12324137  89 SVSIRAVLVDPSQEPKNMEPEKCEGWD----WYDWENLPKPLFWP 129
Cdd:cd04688  79 GFYYLVELSDEALYEQDIFFLEEDGEKlefrWIPLEELDEIDLYP 123

MutT homolog-1 and similar proteins; MutT homolog-1 (MTH1), also known as NUDIX (nucleoside diphosphate-linked moiety X)) motif 1/Nudt1, is a member of the NUDIX hydrolase superfamily. MTH1, the mammalian counterpart of MutT, hydrolyzes oxidized purine nucleoside triphosphates, such as 8-oxo-dGTP and 2-hydroxy-ATP, to monophosphates, thereby preventing the incorporation of such oxygen radicals during replication. This is an important step in the repair mechanism in genomic and mitochondrial DNA. Like other members of the NUDIX family, it requires a divalent cation, such as Mg2+ or Mn2+, for activity, and contain the NUDIX motif, a highly conserved 23-residue block (GX5EX7REUXEEXGU, where U = I, L or V), that functions as a metal binding and catalytic site. MTH1 is predominantly localized in the cytoplasm and mitochondria. Structurally, this enzyme adopts a similar fold to MutT despite low sequence similarity outside the conserved NUDIX motif. The most distinctive structural difference between MutT and MTH1 is the presence of a beta-hairpin, which is absent in MutT. This results in a much deeper and narrower substrate binding pocket. Mechanistically, MTH1 contains dual specificity for nucleotides that contain 2-OH-adenine bases and those that contain 8-oxo-guanine bases.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 12324137  10 VAVVVFILNGNSILLgRRRSSIGNSTFALPGGHLEFGESFEECAAREVMEETGLKIEKMKLLTVT 74
Cdd:cd04699   3 VSVKGVIFDNGRVLL-LRRSRAGAGEWELPGGRLEPGESPEEALKREVKEETGLDVSVGELLDTW 66

uncharacterized NUDIX hydrolase subfamily; NUDIX hydrolase is a superfamily of enzymes found in all three kingdoms of life, and it catalyzes the hydrolysis of NUcleoside DIphosphates linked to other moieties, X. Enzymes belonging to this superfamily require a divalent cation, such as Mg2+ or Mn2+ for their activity. Members of this family are recognized by a highly conserved 23-residue NUDIX motif (GX5EX7REUXEEXGU, where U = I, L or V), which forms a structural motif that functions as a metal binding and catalytic site. Substrates of NUDIX hydrolase include intact and oxidatively damaged nucleoside triphosphates, dinucleoside polyphosphates, nucleotide-sugars and dinucleotide enzymes. These substrates are metabolites or cell signaling molecules that require regulation during different stages of the cell cycle or during periods of stress. In general, the role of the NUDIX hydrolase is to sanitize the nucleotide pools and to maintain cell viability, thereby serving as surveillance and "house-cleaning" enzymes. Substrate specificity is used to define child families within the superfamily. Differences in substrate specificity are determined by the N-terminal extension or by residues in variable loop regions. Mechanistically, substrate hydrolysis occurs by a nucleophilic substitution reaction, with variation in the numbers and roles of divalent cations required. This superfamily consists of at least nine families: IPP (isopentenyl diphosphate) isomerase, ADP ribose pyrophosphatase, mutT pyrophosphohydrolase, coenzyme-A pyrophosphatase, MTH1-7,8-dihydro-8-oxoguanine-triphosphatase, diadenosine tetraphosphate hydrolase, NADH pyrophosphatase, GDP-mannose hydrolase and the c-terminal portion of the mutY adenine glycosylase.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....*..
gi 12324137   9 RVAVVVFILNGNSILLGRRRssiGNSTFALPGGHLEFGESFEECAAREVMEETGLKI 65
Cdd:cd04690   1 IVKAAVIIIKDGRLLLVRKR---GTDAFYLPGGKREPGETPLQALVRELKEELGLDL 54

nucleoside diphosphate-linked moiety X)) motif 17; Nucleoside diphosphate-linked moiety X)) motif 17 (EC 3.6.1.-) encoded by the NUDT17 gene on chromosome 1q21.1 and encodes an enzyme thought to hydrolyse some nucleoside diphosphate derivatives. Members of the NUDIX hydrolase superfamily catalyze the hydrolysis of NUcleoside DIphosphates linked to other moieties, X. Enzymes belonging to this superfamily require a divalent cation, such as Mg2+ or Mn2+, for their activity and contain a highly conserved 23-residue NUDIX motif (GX5EX7REUXEEXGU, where U = I, L or V), which functions as a metal binding and catalytic site. Substrates of NUDIX hydrolases include intact and oxidatively damaged nucleoside triphosphates, dinucleoside polyphosphates, nucleotide-sugars and dinucleotide enzymes. These substrates are metabolites or cell signaling molecules that require regulation during different stages of the cell cycle or during periods of stress. In general, the role of the NUDIX hydrolase is to sanitize the nucleotide pools and to maintain cell viability, thereby serving as surveillance _ "house-cleaning" enzymes. Substrate specificity is used to define families within the superfamily. Differences in substrate specificity are determined by the N-terminal extension or by residues in variable loop regions. Mechanistically, substrate hydrolysis occurs by a nucleophilic substitution reaction, with variation in the numbers and roles of divalent cations required.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 12324137   9 RVAVVVFILNGNS-ILLGRRRSS--IGNSTFALPGGHLEFGESFEECAAREVMEETGLKI---EKMKLLTVTNNVF---- 78
Cdd:cd04694   2 DVGVVVLIEDSDDrVLLTRRAKHmrTFPGVWVPPGGHVELGESLLEAGLRELQEETGLEVsdiQSLSLLGLWESVYptll 81

                        90       100       110
                ....*....|....*....|....*....|....
gi 12324137  79 KEAPTPSHYVSVSIRAVLVDPSQEPKNMEPEKCE 112
Cdd:cd04694  82 SIGLPKRHHIVVYYLVKLSESHENQEQLKLQEDE 115

MutT homolog-1 (MTH1); MutT homolog-1 (MTH1; EC 3.6.1.- ), also called nucleoside diphosphate-linked moiety X)) motif 1 (Nudt1), is a member of the NUDIX hydrolase superfamily. MTH1, the mammalian counterpart of MutT, hydrolyzes oxidized purine nucleoside triphosphates, such as 8-oxo-dGTP and 2-hydroxy-ATP, to monophosphates, thereby preventing the incorporation of such oxygen radicals during replication. This is an important step in the repair mechanism in genomic and mitochondrial DNA. Like other members of the NUDIX family, it requires a divalent cation, such as Mg2+ or Mn2+, for activity, and contain the NUDIX motif, a highly conserved 23-residue block (GX5EX7REUXEEXGU, where U = I, L or V), that functions as a metal binding and catalytic site. MTH1 is predominantly localized in the cytoplasm and mitochondria. Structurally, this enzyme adopts a similar fold to MutT despite low sequence similarity outside the conserved NUDIX motif. The most distinctive structural difference between MutT and MTH1 is the presence of a beta-hairpin, which is absent in MutT. This results in a much deeper and narrower substrate binding pocket. Mechanistically, MTH1 contains dual specificity for nucleotides that contain 2-OH-adenine bases and those that contain 8-oxo-guanine bases.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 12324137   9 RVAVVVFIL-NGNSILLGRRRSSIGNSTFALPGGHLEFGESFEECAAREVMEETGLKIEKMKLLTVTNNVFkEAPTPSHY 87
Cdd:cd03427   1 KLTTLVFVLrGDDRVLLGLKKRGFGAGKWNGFGGKVEPGETIEEAAVRELEEEAGLTATELEKVGRLKFEF-PDDPEAMD 79

                        90       100       110       120
                ....*....|....*....|....*....|....*....|....*
gi 12324137  88 VSVsirAVLVDPSQEPKN---MEPEkcegwdWYDWENLPKPLFWP 129
Cdd:cd03427  80 VHV---FRADSWTGEPQEteeMRPQ------WFDLDDIPYDKMWP 115

UDP-X diphosphatase; UDP-X diphosphatase hydrolyzes UDP-N-acetylmuramic acid and UDP-N-acetylmuramoyl-L-alanine, the last step of the Mur pathway of peptidoglycan biosynthesis. Members of the NUDIX hydrolase superfamily catalyze the hydrolysis of NUcleoside DIphosphates linked to other moieties, X. Enzymes belonging to this superfamily require a divalent cation, such as Mg2+ or Mn2+, for their activity and contain a highly conserved 23-residue NUDIX motif (GX5EX7REUXEEXGU, where U = I, L or V), which functions as a metal binding and catalytic site. Substrates of NUDIX hydrolases include intact and oxidatively damaged nucleoside triphosphates, dinucleoside polyphosphates, nucleotide-sugars and dinucleotide enzymes. These substrates are metabolites or cell signaling molecules that require regulation during different stages of the cell cycle or during periods of stress. In general, the role of the NUDIX hydrolase is to sanitize the nucleotide pools and to maintain cell viability, thereby serving as surveillance _ "house-cleaning" enzymes. Substrate specificity is used to define families within the superfamily. Differences in substrate specificity are determined by the N-terminal extension or by residues in variable loop regions. Mechanistically, substrate hydrolysis occurs by a nucleophilic substitution reaction, with variation in the numbers and roles of divalent cations required.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 12324137   8 PRVAVVVFILNGNSILLGRrrsSIGNSTFALPGGHLEFGESFEECAAREVMEETGLKIEKMKLLTVTN-NVFKEAPTPSH 86
Cdd:cd18891   1 PKVDVRAFIQNENKVLLVQ---DKHTKEWALPGGFAEVGLSPKENILKEVKEETGLHVEVERLLAVFDtDLRQDIPQSFQ 77

                        90       100       110
                ....*....|....*....|....*....|....*..
gi 12324137  87 YVSVSIRAVLVDpSQEPKNMEPEKCegwDWYDWENLP 123
Cdd:cd18891  78 YYKFIFACKILD-GEFQENSETSDL---QYFSLDQLP 110

Antisense Basic Fibroblast Growth Factor; Antisense Basic Fibroblast Growth Factor (ASFGF2; EC 3.6.1.-), also known as nucleoside diphosphate-linked moiety X)) motif 6/Nudt6, and similar proteins including peroxisomal coenzyme A diphosphatase/Nudt7 and mitochondrial coenzyme A diphosphatase/Nudt8. The Nudt6 gene overlaps and lies on the opposite strand from FGF2 gene, and is thought to be the FGF2 antisense gene. The two genes are independently transcribed, and their expression shows an inverse relationship, suggesting that this antisense transcript may regulate FGF2 expression. This gene has also been shown to have hormone-regulatory and antiproliferative actions in the pituitary that are independent of FGF2 expression. Alternatively spliced transcript variants encoding different isoforms have been found for this gene. Members of the NUDIX hydrolase superfamily catalyze the hydrolysis of NUcleoside DIphosphates linked to other moieties, X. Enzymes belonging to this superfamily require a divalent cation, such as Mg2+ or Mn2+, for their activity and contain a highly conserved 23-residue NUDIX motif (GX5EX7REUXEEXGU, where U = I, L or V), which functions as a metal binding and catalytic site. Substrates of NUDIX hydrolases include intact and oxidatively damaged nucleoside triphosphates, dinucleoside polyphosphates, nucleotide-sugars and dinucleotide enzymes. These substrates are metabolites or cell signaling molecules that require regulation during different stages of the cell cycle or during periods of stress. In general, the role of the NUDIX hydrolase is to sanitize the nucleotide pools and to maintain cell viability, thereby serving as surveillance _ "house-cleaning" enzymes. Substrate specificity is used to define families within the superfamily. Differences in substrate specificity are determined by the N-terminal extension or by residues in variable loop regions. Mechanistically, substrate hydrolysis occurs by a nucleophilic substitution reaction, with variation in the numbers and roles of divalent cations required.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|...
gi 12324137  15 FILNGNS-ILLGRRRSSiGNSTFALPGGHLEFGESFEECAAREVMEETGLKIE 66
Cdd:cd04670   8 LVINENNeVLVVQEKYG-GPGGWKLPGGLVDPGEDIGEAAVREVFEETGIDTE 59

NAD(+) diphosphatase;

                         10        20        30        40        50        60
                 ....*....|....*....|....*....|....*....|....*....|....*....|..
gi 12324137    8 PRV--AVVVFILNGNSILLGRRRSSIGN--STFAlpgGHLEFGESFEECAAREVMEETGLKI 65
Cdd:PRK00241 129 PRIapCIIVAVRRGDEILLARHPRHRNGvyTVLA---GFVEVGETLEQCVAREVMEESGIKV 187

uncharacterized NUDIX hydrolase subfamily; NUDIX hydrolase is a superfamily of enzymes found in all three kingdoms of life, and it catalyzes the hydrolysis of NUcleoside DIphosphates linked to other moieties, X. Enzymes belonging to this superfamily require a divalent cation, such as Mg2+ or Mn2+ for their activity. Members of this family are recognized by a highly conserved 23-residue NUDIX motif (GX5EX7REUXEEXGU, where U = I, L or V), which forms a structural motif that functions as a metal binding and catalytic site. Substrates of NUDIX hydrolase include intact and oxidatively damaged nucleoside triphosphates, dinucleoside polyphosphates, nucleotide-sugars and dinucleotide enzymes. These substrates are metabolites or cell signaling molecules that require regulation during different stages of the cell cycle or during periods of stress. In general, the role of the NUDIX hydrolase is to sanitize the nucleotide pools and to maintain cell viability, thereby serving as surveillance and "house-cleaning" enzymes. Substrate specificity is used to define child families within the superfamily. Differences in substrate specificity are determined by the N-terminal extension or by residues in variable loop regions. Mechanistically, substrate hydrolysis occurs by a nucleophilic substitution reaction, with variation in the numbers and roles of divalent cations required. This superfamily consists of at least nine families: IPP (isopentenyl diphosphate) isomerase, ADP ribose pyrophosphatase, mutT pyrophosphohydrolase, coenzyme-A pyrophosphatase, MTH1-7,8-dihydro-8-oxoguanine-triphosphatase, diadenosine tetraphosphate hydrolase, NADH pyrophosphatase, GDP-mannose hydrolase and the c-terminal portion of the mutY adenine glycosylase.

                        10        20        30        40
                ....*....|....*....|....*....|....*....|....*...
gi 12324137  23 LLGRRRSSIGNSTFalPGGHLEFGESFEECAAREVMEETGLKIEKMKL 70
Cdd:cd18875  18 VLDRVKKDWGGYTF--PGGHVEPGESFVDSVIREVKEETGLTIKNPEL 63

ADP-ribose pyrophosphatase and similar proteins; ADP-ribose pyrophosphatase (ADPRase; EC 3.6.1.13) catalyzes the hydrolysis of ADP-ribose to AMP and ribose-5-P. Like other members of the NUDIX hydrolase superfamily of enzymes, it is thought to require a divalent cation, such as Mg2+, for its activity. It also contains a 23-residue NUDIX motif (GX5EX7REUXEEXGU, where U = I, L or V) which functions as a metal binding site/catalytic site. In addition to the NUDIX motif, there are additional conserved amino acid residues, distal from the signature sequence, that correlate with substrate specificity. In humans, there are four distinct ADPRase activities, three putative cytosolic (ADPRase-I, -II, and -Mn) and a single mitochondrial enzyme (ADPRase-m). ADPRase-m is also known as NUDT9. It can be distinugished from the cytosolic ADPRase by a N-terminal target sequence unique to mitochondrial ADPRase. NUDT9 functions as a monomer.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*
gi 12324137   9 RVAVVVFILNGNSILLGRRRSsIGNSTFALPGGHLEFGESFEECAAREVMEETGLKIEKMKLLTVTNNVFKEAPT 83
Cdd:cd18880   1 RIRAKAIIIEDGKLLLVKHRD-EGGIFYILPGGGQEHGETLPEALKRECLEETGLDVEVGDLLFVREYIGPNKPV 74

diadenosine tetraphosphate; Diadenosine tetraphosphate (Ap4A; EC 3.6.1.17), also called NUDIX (nucleoside diphosphate-linked moiety X)) motif 2/Nudt2, is a member of the NUDIX hydrolase superfamily. Ap4A hydrolases are well represented in a variety of prokaryotic and eukaryotic organisms. Phylogenetic analysis reveals two distinct subgroups where plant enzymes fall into one subfamily and fungi/animals/archaea enzymes, represented by this subfamily, fall into another. Bacterial enzymes are found in both subfamilies. Ap4A is a potential by-product of aminoacyl tRNA synthesis, and accumulation of Ap4A has been implicated in a range of biological events, such as DNA replication, cellular differentiation, heat shock, metabolic stress, and apoptosis. Ap4A hydrolase cleaves Ap4A asymmetrically into ATP and AMP. It is important in the invasive properties of bacteria and thus presents a potential target for inhibition of such invasive bacteria. Besides the signature NUDIX motif (G[X5]E[X7]REUXEEXGU, where U is Ile, Leu, or Val) that functions as a metal binding and catalytic site, and a required divalent cation, Ap4A hydrolase is structurally similar to the other members of the NUDIX hydrolase superfamily with some degree of variation. Several regions in the sequences are poorly defined and substrate and metal binding sites are only predicted based on kinetic studies.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....*...
gi 12324137  12 VVVFILNGNSI---LLgrRRSSIGNSTFalPGGHLEFGESFEECAAREVMEETGLKIE 66
Cdd:cd03428   7 AIIYRRDNGEIeflLL--QHSYGGHWDF--PKGHVEPGESELETALRETKEETGLTVD 60

bifunctional nicotinamide-nucleotide adenylyltransferase/Nudix hydroxylase;

                         10        20        30        40        50
                 ....*....|....*....|....*....|....*....|....*....|....*
gi 12324137   11 AVVVfiLNGNsILLGRRRSSIGNSTFALPGGHLEFGESFEECAAREVMEETGLKI 65
Cdd:PRK05379 208 AVVV--QSGH-VLLVRRRAEPGKGLWALPGGFLEQDETLLDACLRELREETGLKL 259

RNA pyrophosphohydrolase; The initiation of mRNA degradation often requires deprotection of its 5' end. In eukaryotes, the 5'-methylguanosine (cap) structure is principally removed by the NUDIX family decapping enzyme Dcp2, yielding a 5'-monophosphorylated RNA that is a substrate for 5' exoribonucleases. In bacteria, the 5'-triphosphate group of primary transcripts is also converted to a 5' monophosphate by a NUDIX protein called RNA pyrophosphohydrolase (RppH), allowing access to both endo- and 5' exoribonucleases. NUDIX hydrolase is a superfamily of enzymes found in all three kingdoms of life, and it catalyzes the hydrolysis of NUcleoside DIphosphates linked to other moieties, X. Enzymes belonging to this superfamily require a divalent cation, such as Mg2+ or Mn2+ for their activity. Members of this family are recognized by a highly conserved 23-residue NUDIX motif (GX5EX7REUXEEXGU, where U = I, L or V), which forms a structural motif that functions as a metal binding and catalytic site. Substrates of NUDIX hydrolase include intact and oxidatively damaged nucleoside triphosphates, dinucleoside polyphosphates, nucleotide-sugars and dinucleotide enzymes. These substrates are metabolites or cell signaling molecules that require regulation during different stages of the cell cycle or during periods of stress. In general, the role of the NUDIX hydrolase is to sanitize the nucleotide pools and to maintain cell viability, thereby serving as surveillance and "house-cleaning" enzymes. Substrate specificity is used to define child families within the superfamily. Differences in substrate specificity are determined by the N-terminal extension or by residues in variable loop regions. Mechanistically, substrate hydrolysis occurs by a nucleophilic substitution reaction, with variation in the numbers and roles of divalent cations required. This superfamily consists of at least nine families: IPP (isopentenyl diphosphate) isomerase, ADP ribose pyrophosphatase, mutT pyrophosphohydrolase, coenzyme-A pyrophosphatase, MTH1-7,8-dihydro-8-oxoguanine-triphosphatase, diadenosine tetraphosphate hydrolase, NADH pyrophosphatase, GDP-mannose hydrolase and the c-terminal portion of the mutY adenine glycosylase.

                        10        20        30        40        50
                ....*....|....*....|....*....|....*....|....*....|....*...
gi 12324137  12 VVVFILNGNSILLGRRRssiGNSTFALPGGHLEFGESFEECAAREVMEETGLKIEKMK 69
Cdd:cd04665   3 VVVIARYKGKWLFTRHK---ERRGWEFPGGKREPGETIEEAARRELYEETGAVIFELK 57

uncharacterized NUDIX hydrolase subfamily; NUDIX hydrolase is a superfamily of enzymes found in all three kingdoms of life, and it catalyzes the hydrolysis of NUcleoside DIphosphates linked to other moieties, X. Enzymes belonging to this superfamily require a divalent cation, such as Mg2+ or Mn2+ for their activity. Members of this family are recognized by a highly conserved 23-residue NUDIX motif (GX5EX7REUXEEXGU, where U = I, L or V), which forms a structural motif that functions as a metal binding and catalytic site. Substrates of NUDIX hydrolase include intact and oxidatively damaged nucleoside triphosphates, dinucleoside polyphosphates, nucleotide-sugars and dinucleotide enzymes. These substrates are metabolites or cell signaling molecules that require regulation during different stages of the cell cycle or during periods of stress. In general, the role of the NUDIX hydrolase is to sanitize the nucleotide pools and to maintain cell viability, thereby serving as surveillance and "house-cleaning" enzymes. Substrate specificity is used to define child families within the superfamily. Differences in substrate specificity are determined by the N-terminal extension or by residues in variable loop regions. Mechanistically, substrate hydrolysis occurs by a nucleophilic substitution reaction, with variation in the numbers and roles of divalent cations required. This superfamily consists of at least nine families: IPP (isopentenyl diphosphate) isomerase, ADP ribose pyrophosphatase, mutT pyrophosphohydrolase, coenzyme-A pyrophosphatase, MTH1-7,8-dihydro-8-oxoguanine-triphosphatase, diadenosine tetraphosphate hydrolase, NADH pyrophosphatase, GDP-mannose hydrolase and the c-terminal portion of the mutY adenine glycosylase.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 12324137   6 AIPRVAVVVFILNGNsILLGRRRssiGNSTFALPGGHLEFGESFEECAAREVMEETGLKIEKMKLLTV 73
Cdd:cd04676  16 FTPSVAAVILNEDGR-ILLQRKG---GLGLWSLPAGAIEPGEHPAEAVIREVREETGLLVKPTRLLGV 79

dihydroneopterin hydrolase; DHNTP pyrophosphatase (DHNTPase) catalyzes the hydrolysis of dihydroneopterin triphosphate (DHNTP) to dihydroneopterin monophosphate (DHNMP) and pyrophosphate,the second step in the pterin branch of the folate synthesis pathway in bacteria. Members of the NUDIX hydrolase superfamily catalyze the hydrolysis of NUcleoside DIphosphates linked to other moieties, X. Enzymes belonging to this superfamily require a divalent cation, such as Mg2+ or Mn2+, for their activity and contain a highly conserved 23-residue NUDIX motif (GX5EX7REUXEEXGU, where U = I, L or V), which functions as a metal binding and catalytic site. Substrates of NUDIX hydrolases include intact and oxidatively damaged nucleoside triphosphates, dinucleoside polyphosphates, nucleotide-sugars and dinucleotide enzymes. These substrates are metabolites or cell signaling molecules that require regulation during different stages of the cell cycle or during periods of stress. In general, the role of the NUDIX hydrolase is to sanitize the nucleotide pools and to maintain cell viability, thereby serving as surveillance _ "house-cleaning" enzymes. Substrate specificity is used to define families within the superfamily. Differences in substrate specificity are determined by the N-terminal extension or by residues in variable loop regions. Mechanistically, substrate hydrolysis occurs by a nucleophilic substitution reaction, with variation in the numbers and roles of divalent cations required.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 12324137  10 VAVVVFILNGNS-ILLGRRRSSIGNSTFAlpGGHLEFGESFEECAAREVMEETGLKIEKMKLLTVTNNVFKEA-----PT 83
Cdd:cd04664   3 VLVVIYRKDEEGeVLLLKRTDDGGFWQSV--TGGIEDGETPWQAALRELKEETGLDPLELQLIDLNVSNFYEIfddwrPG 80

                        90       100       110       120
                ....*....|....*....|....*....|....*....|....*.
gi 12324137  84 PSHYVsVSIRAVLVDPSQEPKnMEPEKCEgWDWYDWENLPKPLFWP 129
Cdd:cd04664  81 VTVNT-EHVFAVEVPEEQPIR-LSPEHTD-YRWLPYEEAAELLFWP 123

Bdellovibrio Bacteriovorus nucleoside diphosphate sugar hydrolase, and similar proteins; Bdellovibrio bacteriovorus nucleoside diphosphate sugar (NDPS) hydrolase Bd3179 has been shown to similarities to the Escherichia coli adenosine diphosphate ribose (ADPR) hydrolase and the guanosine diphosphate mannose (GDPM) hydrolase. It may have a role when Bdellovibrio degrades and metabolizes host cell. ADP-ribose pyrophosphatase (ADPRase) catalyzes the hydrolysis of ADP-ribose and a variety of additional ADP-sugar conjugates to AMP and ribose-5-phosphate. In humans, there are four distinct ADPRase activities, three putative cytosolic enzymes (ADPRase-I, -II, and -Mn) and a single mitochondrial enzyme (ADPRase-m). Human ADPRase-II is also referred to as NUDT5. It lacks the N-terminal target sequence unique to mitochondrial ADPRase. The different cytosolic types are distinguished by their specificities for substrate and specific requirement for metal ions. NUDT5 forms a homodimer. It also contains a highly conserved 23-residue NUDIX motif (GX5EX7REUXEEXGU, where U = I, L or V) which functions as a metal binding site/catalytic site. In addition to the NUDIX motif, there are additional conserved amino acid residues, distal from the signature sequence, that correlate with substrate specificity. UDP-glucose pyrophosphatase (UGPPase) (EC 3.6.1.45; also known as nucleoside diphosphate-linked moiety X)) motif 14; Nudt14) hydrolyzes the pyrophosphate of the nucleoside diphosphate sugar to generate glucose-1-P and UMP. In mammals, UDP-glucose is the glucosyl donor for the synthesis of the storage polysaccharide glycogen. UGPPase, as a regulator of UDP-glucose, could play a regulatory role, but it has been shown to prefer ADP-ribose over UDP-glucose. Like other members of the NUDIX hydrolase superfamily, it requires a divalent cation, such as Mg2+, for its activity. It also contains a highly conserved 23-residue NUDIX motif (GX5EX7REUXEEXGU, where U = I, L or V) which functions as a metal binding site/catalytic site.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|....*...
gi 12324137  10 VAVVVFILNGNSILLGRRRSSIGNSTFALPGGHLEFGESFEECAAREVMEETGLKIEKMKLLTVTNNV 77
Cdd:cd24159  44 VAVVPLLDDGRVVMERQYRYPLKRVFLEFPAGKIDPGEDTLETAKRELLEETGYEAQEWAFLTTIHPA 111

uncharacterized NUDIX hydrolase subfamily; NUDIX hydrolase is a superfamily of enzymes found in all three kingdoms of life, and it catalyzes the hydrolysis of NUcleoside DIphosphates linked to other moieties, X. Enzymes belonging to this superfamily require a divalent cation, such as Mg2+ or Mn2+ for their activity. Members of this family are recognized by a highly conserved 23-residue NUDIX motif (GX5EX7REUXEEXGU, where U = I, L or V), which forms a structural motif that functions as a metal binding and catalytic site. Substrates of NUDIX hydrolase include intact and oxidatively damaged nucleoside triphosphates, dinucleoside polyphosphates, nucleotide-sugars and dinucleotide enzymes. These substrates are metabolites or cell signaling molecules that require regulation during different stages of the cell cycle or during periods of stress. In general, the role of the NUDIX hydrolase is to sanitize the nucleotide pools and to maintain cell viability, thereby serving as surveillance and "house-cleaning" enzymes. Substrate specificity is used to define child families within the superfamily. Differences in substrate specificity are determined by the N-terminal extension or by residues in variable loop regions. Mechanistically, substrate hydrolysis occurs by a nucleophilic substitution reaction, with variation in the numbers and roles of divalent cations required. This superfamily consists of at least nine families: IPP (isopentenyl diphosphate) isomerase, ADP ribose pyrophosphatase, mutT pyrophosphohydrolase, coenzyme-A pyrophosphatase, MTH1-7,8-dihydro-8-oxoguanine-triphosphatase, diadenosine tetraphosphate hydrolase, NADH pyrophosphatase, GDP-mannose hydrolase and the c-terminal portion of the mutY adenine glycosylase.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 12324137   7 IPRVAVVVFILNGNsILLGRRRSsigNSTFALPGGHLEFGESFEECAAREVMEETGLKIEKMKLLTV 73
Cdd:cd18879  18 LPGVTAVVLRDAGR-VLLVRRAD---NGRWTPVTGIVEPGEQPADAAVREVLEETGVDVEVERLASV 80

uncharacterized NUDIX hydrolase subfamily; NUDIX hydrolase is a superfamily of enzymes found in all three kingdoms of life, and it catalyzes the hydrolysis of NUcleoside DIphosphates linked to other moieties, X. Enzymes belonging to this superfamily require a divalent cation, such as Mg2+ or Mn2+ for their activity. Members of this family are recognized by a highly conserved 23-residue NUDIX motif (GX5EX7REUXEEXGU, where U = I, L or V), which forms a structural motif that functions as a metal binding and catalytic site. Substrates of NUDIX hydrolase include intact and oxidatively damaged nucleoside triphosphates, dinucleoside polyphosphates, nucleotide-sugars and dinucleotide enzymes. These substrates are metabolites or cell signaling molecules that require regulation during different stages of the cell cycle or during periods of stress. In general, the role of the NUDIX hydrolase is to sanitize the nucleotide pools and to maintain cell viability, thereby serving as surveillance and "house-cleaning" enzymes. Substrate specificity is used to define child families within the superfamily. Differences in substrate specificity are determined by the N-terminal extension or by residues in variable loop regions. Mechanistically, substrate hydrolysis occurs by a nucleophilic substitution reaction, with variation in the numbers and roles of divalent cations required. This superfamily consists of at least nine families: IPP (isopentenyl diphosphate) isomerase, ADP ribose pyrophosphatase, mutT pyrophosphohydrolase, coenzyme-A pyrophosphatase, MTH1-7,8-dihydro-8-oxoguanine-triphosphatase, diadenosine tetraphosphate hydrolase, NADH pyrophosphatase, GDP-mannose hydrolase and the c-terminal portion of the mutY adenine glycosylase.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 12324137  38 LPGGHLEFGESFEECAAREVMEETGLKI-EKMKLLTVTNNvfkEAPTPSHYVSVSI-RAVLVDPSQEPkNMEPEKCegwD 115
Cdd:cd04680  27 LPGGGVDKGETAEEAARRELREEAGVVLtGPPRLFGVYFN---RRVSPRDHVALYRvREFEQTEPPEP-NGEIAEA---G 99

                ....*...
gi 12324137 116 WYDWENLP 123
Cdd:cd04680 100 FFALDALP 107

uncharacterized NUDIX hydrolase subfamily; Contains a crystal structure of the NUDIX hydrolase from Enterococcus faecalis, which has an unknown function. NUDIX hydrolase is a superfamily of enzymes found in all three kingdoms of life, and it catalyzes the hydrolysis of NUcleoside DIphosphates linked to other moieties, X. Enzymes belonging to this superfamily require a divalent cation, such as Mg2+ or Mn2+ for their activity. Members of this family are recognized by a highly conserved 23-residue NUDIX motif (GX5EX7REUXEEXGU, where U = I, L or V), which forms a structural motif that functions as a metal binding and catalytic site. Substrates of NUDIX hydrolase include intact and oxidatively damaged nucleoside triphosphates, dinucleoside polyphosphates, nucleotide-sugars and dinucleotide enzymes. These substrates are metabolites or cell signaling molecules that require regulation during different stages of the cell cycle or during periods of stress. In general, the role of the NUDIX hydrolase is to sanitize the nucleotide pools and to maintain cell viability, thereby serving as surveillance and "house-cleaning" enzymes. Substrate specificity is used to define child families within the superfamily. Differences in substrate specificity are determined by the N-terminal extension or by residues in variable loop regions. Mechanistically, substrate hydrolysis occurs by a nucleophilic substitution reaction, with variation in the numbers and roles of divalent cations required. This superfamily consists of at least nine families: IPP (isopentenyl diphosphate) isomerase, ADP ribose pyrophosphatase, mutT pyrophosphohydrolase, coenzyme-A pyrophosphatase, MTH1-7,8-dihydro-8-oxoguanine-triphosphatase, diadenosine tetraphosphate hydrolase, NADH pyrophosphatase, GDP-mannose hydrolase and the c-terminal portion of the mutY adenine glycosylase.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|.
gi 12324137   7 IPRVAVVVFILNGNS-ILLgrrrSSIGNSTFALPGGHLEFGESFEECAAREVMEETGLKIE 66
Cdd:cd04684  13 KDRPGAYAVIFNDEGkVLL----VQTPNGGYFLPGGGIEPGETPEEALHREVLEETGWEIE 69

CDP-choline pyrophosphatase; CDP-choline pyrophosphatase catalyzes the hydrolysis of CDP-choline to produce CMP and phosphocholine. Members of the NUDIX hydrolase superfamily catalyze the hydrolysis of NUcleoside DIphosphates linked to other moieties, X. Enzymes belonging to this superfamily require a divalent cation, such as Mg2+ or Mn2+, for their activity and contain a highly conserved 23-residue NUDIX motif (GX5EX7REUXEEXGU, where U = I, L or V), which functions as a metal binding and catalytic site. Substrates of NUDIX hydrolases include intact and oxidatively damaged nucleoside triphosphates, dinucleoside polyphosphates, nucleotide-sugars and dinucleotide enzymes. These substrates are metabolites or cell signaling molecules that require regulation during different stages of the cell cycle or during periods of stress. In general, the role of the NUDIX hydrolase is to sanitize the nucleotide pools and to maintain cell viability, thereby serving as surveillance _ "house-cleaning" enzymes. Substrate specificity is used to define families within the superfamily. Differences in substrate specificity are determined by the N-terminal extension or by residues in variable loop regions. Mechanistically, substrate hydrolysis occurs by a nucleophilic substitution reaction, with variation in the numbers and roles of divalent cations required.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 12324137   8 PRVAVVVFILN-GNSILLGRRRSsigNSTFALPGGHLEFGESFEECAAREVMEETGLKIEKMKLLTVTNNVFKEAPTPSH 86
Cdd:cd18890   1 PKVDIRAVVFNdKEEILLVKEKE---DGKWTLPGGWADVGYTPTEVAAKEVEEETGLEVSPKKLLAILDKRKHPHPPQPT 77

                ..
gi 12324137  87 YV 88
Cdd:cd18890  78 YV 79

plant diadenosine tetraphosphate (Ap4A) hydrolase and similar proteins; Diadenosine tetraphosphate (Ap4A) hydrolase is a member of the NUDIX hydrolase superfamily. Members of this family are well represented in a variety of prokaryotic and eukaryotic organisms. Phylogenetic analysis reveals two distinct subgroups where plant enzymes fall into one group (represented by this subfamily) and fungi/animals/archaea enzymes fall into another. Bacterial enzymes are found in both subfamilies. Ap4A is a potential by-product of aminoacyl tRNA synthesis, and accumulation of Ap4A has been implicated in a range of biological events, such as DNA replication, cellular differentiation, heat shock, metabolic stress, and apoptosis. Ap4A hydrolase cleaves Ap4A asymmetrically into ATP and AMP. It is important in the invasive properties of bacteria and thus presents a potential target for the inhibition of such invasive bacteria. Besides the signature NUDIX motif (G[X5]E[X7]REUXEEXGU where U is Ile, Leu, or Val), Ap4A hydrolase is structurally similar to the other members of the NUDIX hydrolase superfamily with some degree of variations. Several regions in the sequences are poorly defined and substrate and metal binding sites are only predicted based on kinetic studies.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|....
gi 12324137   8 PRVAVVVFILNGNsILLGRRRSSIGNstFALPGGHLEFGESFEECAAREVMEETGLKIEKMKLL 71
Cdd:cd03671   4 PNVGIVLFNRDGQ-VLVGRRIDVPGA--WQFPQGGIDEGEDPEEAALRELYEETGLSPEDVEII 64

uncharacterized NUDIX hydrolase subfamily; Contains a crystal structure of the NUDIX hydrolase from Nitrosomonas europaea, which has an unknown function. NUDIX hydrolase is a superfamily of enzymes found in all three kingdoms of life, and it catalyzes the hydrolysis of NUcleoside DIphosphates linked to other moieties, X. Enzymes belonging to this superfamily require a divalent cation, such as Mg2+ or Mn2+ for their activity. Members of this family are recognized by a highly conserved 23-residue NUDIX motif (GX5EX7REUXEEXGU, where U = I, L or V), which forms a structural motif that functions as a metal binding and catalytic site. Substrates of NUDIX hydrolase include intact and oxidatively damaged nucleoside triphosphates, dinucleoside polyphosphates, nucleotide-sugars and dinucleotide enzymes. These substrates are metabolites or cell signaling molecules that require regulation during different stages of the cell cycle or during periods of stress. In general, the role of the NUDIX hydrolase is to sanitize the nucleotide pools and to maintain cell viability, thereby serving as surveillance and "house-cleaning" enzymes. Substrate specificity is used to define child families within the superfamily. Differences in substrate specificity are determined by the N-terminal extension or by residues in variable loop regions. Mechanistically, substrate hydrolysis occurs by a nucleophilic substitution reaction, with variation in the numbers and roles of divalent cations required. This superfamily consists of at least nine families: IPP (isopentenyl diphosphate) isomerase, ADP ribose pyrophosphatase, mutT pyrophosphohydrolase, coenzyme-A pyrophosphatase, MTH1-7,8-dihydro-8-oxoguanine-triphosphatase, diadenosine tetraphosphate hydrolase, NADH pyrophosphatase, GDP-mannose hydrolase and the c-terminal portion of the mutY adenine glycosylase.

                        10        20        30
                ....*....|....*....|....*....|....*
gi 12324137  32 GNSTFALPGGHLEFGESFEECAAREVMEETGLKIE 66
Cdd:cd03675  22 GRLVLNQPAGHLEPGESLLEAAIRETLEETGWEVE 56

mRNA decapping enzyme 2; mRNA decapping enzyme 2 (Dcp2p; EC 3.6.1.62), nucleoside diphosphate linked moiety X))-type motif 20/Nudt20, is required for degradation of mRNAs, both in normal mRNA turnover, and in nonsense-mediated mRNA decay (NMD). Its catalytic subunit, and Dcp1p are the two components of the decapping enzyme complex. Decapping is a key step in both general and nonsense-mediated 5'->3' mRNA-decay pathways. Dcp2p contains an all-alpha helical N-terminal domain and a C-terminal domain which has the NUDIX fold. While decapping is not dependent on the N-terminus of Dcp2p, it does affect its efficiency. Dcp1p binds the N-terminal domain of Dcp2p stimulating the decapping activity of Dcp2p. Decapping permits the degradation of the transcript and is a site of numerous control inputs. It is responsible for nonsense-mediated decay as well as AU-rich element (ARE)-mediated decay. In addition, it may also play a role in the levels of mRNA. Enzymes belonging to the NUDIX hydrolase superfamily require a divalent cation, such as Mg2+ or Mn2+, for their activity and are recognized by a highly conserved 23-residue NUDIX motif (GX5EX7REUXEEXGU, where U = I, L or V).

                        10        20        30
                ....*....|....*....|....*....|....*.
gi 12324137  32 GNSTFALPGGHLEFGESFEECAAREVMEETGLKIEK 67
Cdd:cd03672  24 SNSSWGFPKGKINKDESDADCAIREVYEETGFDISD 59

MutT homolog-1 and similar proteins; MutT homolog-1 (MTH1), also known as NUDIX (nucleoside diphosphate-linked moiety X)) motif 1/Nudt1, is a member of the NUDIX hydrolase superfamily. MTH1, the mammalian counterpart of MutT, hydrolyzes oxidized purine nucleoside triphosphates, such as 8-oxo-dGTP and 2-hydroxy-ATP, to monophosphates, thereby preventing the incorporation of such oxygen radicals during replication. This is an important step in the repair mechanism in genomic and mitochondrial DNA. Like other members of the NUDIX family, it requires a divalent cation, such as Mg2+ or Mn2+, for activity, and contain the NUDIX motif, a highly conserved 23-residue block (GX5EX7REUXEEXGU, where U = I, L or V), that functions as a metal binding and catalytic site. MTH1 is predominantly localized in the cytoplasm and mitochondria. Structurally, this enzyme adopts a similar fold to MutT despite low sequence similarity outside the conserved NUDIX motif. The most distinctive structural difference between MutT and MTH1 is the presence of a beta-hairpin, which is absent in MutT. This results in a much deeper and narrower substrate binding pocket. Mechanistically, MTH1 contains dual specificity for nucleotides that contain 2-OH-adenine bases and those that contain 8-oxo-guanine bases.

                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 12324137  16 ILNGNSILLGRrrsSIGNSTFALPGGHLEFGESFEECAAREVMEETGLKIEKMKLLTVTNNVFkEAPTPSHYVSVSIRAV 95
Cdd:cd18883   7 IISDEHLLLAR---VKGDDKTFLPGGHIEIGESAEIALVRELREELGLSCKVGRYLGAVENQW-QDKEVIHVELNHLFEV 82

                        90
                ....*....|....*.
gi 12324137  96 LV---DPSQEPKNMEP 108
Cdd:cd18883  83 ELqdlHTSDTPESQEP 98

Isopentenyldiphosphate isomerase [Lipid transport and metabolism]; Isopentenyldiphosphate isomerase is part of the Pathway/BioSystem: Isoprenoid biosynthesis

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|....
gi 12324137  11 AVVVFILNGNS-ILLGRRrsSIGNSTFalPG-------GHLEFGESFEECAAREVMEETGLKIE 66
Cdd:COG1443  31 AFSVFVFNSDGrLLLQRR--ALTKDHW--PGlwdntvcGHPRAGETYEEAAVRELEEELGITVD 90

uncharacterized NUDIX hydrolase subfamily; NUDIX hydrolase is a superfamily of enzymes found in all three kingdoms of life, and it catalyzes the hydrolysis of NUcleoside DIphosphates linked to other moieties, X. Enzymes belonging to this superfamily require a divalent cation, such as Mg2+ or Mn2+ for their activity. Members of this family are recognized by a highly conserved 23-residue NUDIX motif (GX5EX7REUXEEXGU, where U = I, L or V), which forms a structural motif that functions as a metal binding and catalytic site. Substrates of NUDIX hydrolase include intact and oxidatively damaged nucleoside triphosphates, dinucleoside polyphosphates, nucleotide-sugars and dinucleotide enzymes. These substrates are metabolites or cell signaling molecules that require regulation during different stages of the cell cycle or during periods of stress. In general, the role of the NUDIX hydrolase is to sanitize the nucleotide pools and to maintain cell viability, thereby serving as surveillance and "house-cleaning" enzymes. Substrate specificity is used to define child families within the superfamily. Differences in substrate specificity are determined by the N-terminal extension or by residues in variable loop regions. Mechanistically, substrate hydrolysis occurs by a nucleophilic substitution reaction, with variation in the numbers and roles of divalent cations required. This superfamily consists of at least nine families: IPP (isopentenyl diphosphate) isomerase, ADP ribose pyrophosphatase, mutT pyrophosphohydrolase, coenzyme-A pyrophosphatase, MTH1-7,8-dihydro-8-oxoguanine-triphosphatase, diadenosine tetraphosphate hydrolase, NADH pyrophosphatase, GDP-mannose hydrolase and the c-terminal portion of the mutY adenine glycosylase.

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gi 12324137  40 GGHLEFGESFEECAAREVMEETGLKIEKMKLL 71
Cdd:cd04692  62 AGHIDAGETYEEAAVRELEEELGLTVSPEDLI 93

ADP-ribose pyrophosphatase; ADP-ribose pyrophosphatase (ADPRase; EC 3.6.1.13) catalyzes the hydrolysis of ADP-ribose to AMP and ribose-5-P. Like other members of the NUDIX hydrolase superfamily of enzymes, it is thought to require a divalent cation, such as Mg2+, for its activity. It also contains a 23-residue NUDIX motif (GX5EX7REUXEEXGU, where U = I, L or V) which functions as a metal binding site/catalytic site. In addition to the NUDIX motif, there are additional conserved amino acid residues, distal from the signature sequence, that correlate with substrate specificity. In humans, there are four distinct ADPRase activities, three putative cytosolic (ADPRase-I, -II, and -Mn) and a single mitochondrial enzyme (ADPRase-m). ADPRase-m is also known as NUDT9. It can be distinugished from the cytosolic ADPRase by a N-terminal target sequence unique to mitochondrial ADPRase. NUDT9 functions as a monomer.

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gi 12324137   8 PRVAVVVFILNGNSILLGRRRssigNSTFALPGGHLEFGESFEECAAREVMEETGLKIEKMKLLTV 73
Cdd:cd18889   1 PKIDTRAAIFKDDKILLVQEK----DGRWSLPGGWVDVNQSIKENTIKEAKEEAGLDVEPKRIIAV 62