Gamma carbonic anhydrase-like: This family is composed of gamma carbonic anhydrase (CA), Ferripyochelin Binding Protein (FBP), E. coli paaY protein, and similar proteins. CAs are zinc-containing enzymes that catalyze the reversible hydration of carbon dioxide in a two-step mechanism, involving the nucleophilic attack of a zinc-bound hydroxide ion on carbon dioxide, followed by the regeneration of the active site by ionization of the zinc-bound water molecule and removal of a proton from the active site. They are ubiquitous enzymes involved in fundamental processes like photosynthesis, respiration, pH homeostasis and ion transport. There are three evolutionary distinct groups - alpha, beta and gamma carbonic anhydrases - which show no significant sequence identity or structural similarity. Gamma CAs are trimeric enzymes with left-handed parallel beta helix (LbH) structural domain.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 530556352   2 EHPVLLGDHVFISPHATLLGCSIEQASYIATGATILHGATVKEGAVVAVGgivhakTVIPSGFIVPPNMIAIGNPVKLYA 81
Cdd:cd04645   58 GYPTIIGDNVTVGHGAVLHGCTIGDNCLIGMGAIILDGAVIGKGSIVAAG------SLVPPGKVIPPGSLVAGSPAKVVR 131

                         90
                 ....*....|...
gi 530556352  82 PNDKELMQAIKTN 94
Cdd:cd04645  132 ELTDEEIAELRES 144

sugar O-acyltransferase, sialic acid O-acetyltransferase NeuD family; This family of proteins includes the characterized NeuD sialic acid O-acetyltransferase enzymes from E. coli and Streptococcus agalactiae (group B strep). These two are quite closely related to one another, so extension of this annotation to other members of the family in unsupported without additional independent evidence. The neuD gene is often observed in close proximity to the neuABC genes for the biosynthesis of CMP-N-acetylneuraminic acid (CMP-sialic acid), and NeuD sequences from these organisms were used to construct the seed for this model. Nevertheless, there are numerous instances of sequences identified by this model which are observed in a different genomic context (although almost universally in exopolysaccharide biosynthesis-related loci), as well as in genomes for which the biosynthesis of sialic acid (SA) is undemonstrated. Even in the cases where the association with SA biosynthesis is strong, it is unclear in the literature whether the biological substrate is SA iteself, CMP-SA, or a polymer containing SA. Similarly, it is unclear to what extent the enzyme has a preference for acetylation at the 7, 8 or 9 positions. In the absence of evidence of association with SA, members of this family may be involved with the acetylation of differring sugar substrates, or possibly the delivery of alternative acyl groups. The closest related sequences to this family (and those used to root the phylogenetic tree constructed to create this model) are believed to be succinyltransferases involved in lysine biosynthesis. These proteins contain repeats of the bacterial transferase hexapeptide (pfam00132), although often these do not register above the trusted cutoff.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 530556352    1 MEHPVLLGDHVFISPHATLLG-CSIEQASYIATGATILHGATVKEGAVVAVGGIVHAKtvipsgfiVPPNMIAIGNP 76
Cdd:TIGR03570 132 VEHDCVIGDFVHIAPGVTLSGgVVIGEGVFIGAGATIIQGVTIGAGAIVGAGAVVTKD--------IPDGGVVVGVP 200

Gamma carbonic anhydrase-like: This family is composed of gamma carbonic anhydrase (CA), Ferripyochelin Binding Protein (FBP), E. coli paaY protein, and similar proteins. CAs are zinc-containing enzymes that catalyze the reversible hydration of carbon dioxide in a two-step mechanism, involving the nucleophilic attack of a zinc-bound hydroxide ion on carbon dioxide, followed by the regeneration of the active site by ionization of the zinc-bound water molecule and removal of a proton from the active site. They are ubiquitous enzymes involved in fundamental processes like photosynthesis, respiration, pH homeostasis and ion transport. There are three evolutionary distinct groups - alpha, beta and gamma carbonic anhydrases - which show no significant sequence identity or structural similarity. Gamma CAs are trimeric enzymes with left-handed parallel beta helix (LbH) structural domain.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 530556352   2 EHPVLLGDHVFISPHATLLGCSIEQASYIATGATILHGATVKEGAVVAVGgivhakTVIPSGFIVPPNMIAIGNPVKLYA 81
Cdd:cd04645   58 GYPTIIGDNVTVGHGAVLHGCTIGDNCLIGMGAIILDGAVIGKGSIVAAG------SLVPPGKVIPPGSLVAGSPAKVVR 131

                         90
                 ....*....|...
gi 530556352  82 PNDKELMQAIKTN 94
Cdd:cd04645  132 ELTDEEIAELRES 144

Putative Acyltransferase (AT), Left-handed parallel beta-Helix (LbH) domain; This group is composed of mostly uncharacterized proteins containing an N-terminal helical subdomain followed by a LbH domain. The alignment contains 6 turns, each containing three imperfect tandem repeats of a hexapeptide repeat motif (X-[STAV]-X-[LIV]-[GAED]-X). Proteins containing hexapeptide repeats are often enzymes showing acyltransferase activity. A few members are identified as NeuD, a sialic acid (Sia) O-acetyltransferase that is required for Sia synthesis and surface polysaccharide sialylation.

                         10        20        30        40        50        60        70
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*.
gi 530556352   2 EHPVLLGDHVFISPHATLLG-CSIEQASYIATGATILHGATVKEGAVVAVGGIVHAKtvipsgfiVPPNMIAIGNP 76
Cdd:cd03360  130 GHDCVIGDFVHIAPGVVLSGgVTIGEGAFIGAGATIIQGVTIGAGAIIGAGAVVTKD--------VPDGSVVVGNP 197

Acetyltransferase, isoleucine patch superfamily [General function prediction only];

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 530556352   3 HPVLLGDHVFISPHATLLGCS-----------------IEQASYIATGATILHGATVKEGAVVAVGGIVHAKtvipsgfi 65
Cdd:COG0110   46 GGITIGDNVLIGPGVTILTGNhpiddpatfplrtgpvtIGDDVWIGAGATILPGVTIGDGAVVGAGSVVTKD-------- 117

                         90
                 ....*....|...
gi 530556352  66 VPPNMIAIGNPVK 78
Cdd:COG0110  118 VPPYAIVAGNPAR 130

paaY-like: This group is composed by uncharacterized proteins with similarity to the protein product of the E. coli paaY gene, which is part of the paa gene cluster responsible for phenylacetic acid degradation. Proteins in this group are expected to adopt the left-handed parallel beta-helix (LbH) structure. They contain imperfect tandem repeats of a hexapeptide repeat motif (X-[STAV]-X-[LIV]-[GAED]-X). Similarity to gamma carbonic anhydrase and Ferripyochelin Binding Protein (FBP) may suggest metal binding capacity.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 530556352   5 VLLGDHVFISPHATLLG--------------------------CSIEQASYIATGAtILHGATVKEGAVV---------A 49
Cdd:cd04745   19 VIIGKNCYIGPHASLRGdfgrivirdganvqdncvihgfpgqdTVLEENGHIGHGA-ILHGCTIGRNALVgmnavvmdgA 97

                         90       100       110
                 ....*....|....*....|....*....|..
gi 530556352  50 VGG---IVHAKTVIPSGFIVPPNMIAIGNPVK 78
Cdd:cd04745   98 VIGeesIVGAMAFVKAGTVIPPRSLIAGSPAK 129

wcaF-like: This group is composed of the protein product of the E. coli wcaF gene and similar proteins. WcaF is part of the gene cluster responsible for the biosynthesis of the extracellular polysaccharide colanic acid. The wcaF protein is predicted to contain a left-handed parallel beta-helix (LbH) domain encoded by imperfect tandem repeats of a hexapeptide repeat motif (X-[STAV]-X-[LIV]-[GAED]-X). Proteins containing hexapeptide repeats are often enzymes showing acyltransferase activity. Many are trimeric in their active forms.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 530556352   4 PVLLGDHVFISPHATLLGCS----------------IEQASYIATGATILHGATVKEGAVVAVGGIVHAktvipsgfIVP 67
Cdd:cd05825   23 PVTIGSDACISQGAYLCTGShdyrspafplitapivIGDGAWVAAEAFVGPGVTIGEGAVVGARSVVVR--------DLP 94

                         90
                 ....*....|.
gi 530556352  68 PNMIAIGNPVK 78
Cdd:cd05825   95 AWTVYAGNPAV 105

Maltose O-acyltransferase (MAT)-like: This family is composed of maltose O-acetyltransferase, galactoside O-acetyltransferase (GAT), xenobiotic acyltransferase (XAT) and similar proteins. MAT and GAT catalyze the CoA-dependent acetylation of the 6-hydroxyl group of their respective sugar substrates. MAT acetylates maltose and glucose exclusively while GAT specifically acetylates galactopyranosides. XAT catalyzes the CoA-dependent acetylation of a variety of hydroxyl-bearing acceptors such as chloramphenicol and streptogramin, among others. XATs are implicated in inactivating xenobiotics leading to xenobiotic resistance in patients. Members of this family contain a a left-handed parallel beta-helix (LbH) domain with at least 5 turns, each containing three imperfect tandem repeats of a hexapeptide repeat motif (X-[STAV]-X-[LIV]-[GAED]-X). They are trimeric in their active form.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 530556352   8 GDHVFISPHATLLGCS--------------------IEQASYIATGATILHGATVKEGAVVAVGGIVHAktvipsgfIVP 67
Cdd:cd04647   25 GDNVLIGPNVTIYDHNhdiddperpieqgvtsapivIGDDVWIGANVVILPGVTIGDGAVVGAGSVVTK--------DVP 96

                         90
                 ....*....|.
gi 530556352  68 PNMIAIGNPVK 78
Cdd:cd04647   97 PNSIVAGNPAK 107

serine O-acetyltransferase

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 530556352   6 LLGDHVFISPHATLLGC---------SIEQASYIATGATILHGATVKEGAVVAVGGIVHAKtvipsgfiVPPNMIAIGNP 76
Cdd:PLN02694 188 VIGNNVSILHHVTLGGTgkacgdrhpKIGDGVLIGAGATILGNVKIGEGAKIGAGSVVLID--------VPPRTTAVGNP 259

                 ....*....
gi 530556352  77 VKLYAPNDK 85
Cdd:PLN02694 260 ARLVGGKEK 268

Maltose O-acetyltransferase (MAT) and Galactoside O-acetyltransferase (GAT): MAT and GAT catalyze the CoA-dependent acetylation of the 6-hydroxyl group of their respective sugar substrates. MAT acetylates maltose and glucose exclusively at the C6 position of the nonreducing end glucosyl moiety. GAT specifically acetylates galactopyranosides. Furthermore, MAT shows higher affinity toward artificial substrates containing an alkyl or hydrophobic chain as well as a glucosyl unit. Active MAT and GAT are homotrimers, with each subunit consisting of an N-terminal alpha-helical region and a C-terminal left-handed parallel alpha-helix (LbH) subdomain with 6 turns, each containing three imperfect tandem repeats of a hexapeptide repeat motif (X-[STAV]-X-[LIV]-[GAED]-X).

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 530556352   4 PVLLGDHVFISPHATLL--GCSIEQAS-----------------YIATGATILHGATVKEGAVVAVGGIVhAKTVipsgf 64
Cdd:cd03357   82 PVTIGDNVLIGPNVQIYtaGHPLDPEErnrgleyakpitigdnvWIGGGVIILPGVTIGDNSVIGAGSVV-TKDI----- 155

                         90
                 ....*....|..
gi 530556352  65 ivPPNMIAIGNP 76
Cdd:cd03357  156 --PANVVAAGNP 165