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Conserved domains on  [gi|15596778|ref|NP_250272|]
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succinate dehydrogenase subunit C [Pseudomonas aeruginosa PAO1]

Protein Classification

SdhC family protein( domain architecture ID 10005170)

SdhC family protein

Graphical summary

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List of domain hits

 Name Accession Description Interval E-value
SdhC COG2009
Succinate dehydrogenase/fumarate reductase, cytochrome b subunit [Energy production and ...
 5-128 1.46e-50

Succinate dehydrogenase/fumarate reductase, cytochrome b subunit [Energy production and conversion];


:

Pssm-ID: 441612  Cd Length: 128  Bit Score: 156.48  E-value: 1.46e-50
                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 15596778   5 VNSKRPVNLDLRTIKLPVTAYTSILHRISGVILFLGIAVLLFALDKSLSSEEGFEQVKACLTSPLAKLVIWGLLSALLYH 84
Cdd:COG2009   3 VKKNRPLSPHLQIYRLPLTMIVSILHRITGVALFLGLPLLVWWLAASASSPEAFAAVQAFLGSPLGKLVLLGLTWALLYH 82

                        90       100       110       120
                ....*....|....*....|....*....|....*....|....
gi 15596778  85 LVAGVRHLVMDAGVGETLEGGKRGSKIVIAIAVVLIVLAGVWVW 128
Cdd:COG2009  83 LLAGIRHLLWDFGYGFELETARRSAWVVLVLSVVLTVLLGVVLW 126
 
Name Accession Description Interval E-value
SdhC COG2009
Succinate dehydrogenase/fumarate reductase, cytochrome b subunit [Energy production and ...
 5-128 1.46e-50

Succinate dehydrogenase/fumarate reductase, cytochrome b subunit [Energy production and conversion];


Pssm-ID: 441612  Cd Length: 128  Bit Score: 156.48  E-value: 1.46e-50
                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 15596778   5 VNSKRPVNLDLRTIKLPVTAYTSILHRISGVILFLGIAVLLFALDKSLSSEEGFEQVKACLTSPLAKLVIWGLLSALLYH 84
Cdd:COG2009   3 VKKNRPLSPHLQIYRLPLTMIVSILHRITGVALFLGLPLLVWWLAASASSPEAFAAVQAFLGSPLGKLVLLGLTWALLYH 82

                        90       100       110       120
                ....*....|....*....|....*....|....*....|....
gi 15596778  85 LVAGVRHLVMDAGVGETLEGGKRGSKIVIAIAVVLIVLAGVWVW 128
Cdd:COG2009  83 LLAGIRHLLWDFGYGFELETARRSAWVVLVLSVVLTVLLGVVLW 126
succ_dehyd_cytB TIGR02970
succinate dehydrogenase, cytochrome b556 subunit; In E. coli and many other bacteria, two ...
 7-126 1.26e-44

succinate dehydrogenase, cytochrome b556 subunit; In E. coli and many other bacteria, two small, hydrophobic, mutually homologous subunits of succinate dehydrogenase, a TCA cycle enzyme, are SdhC and SdhD. This family is the SdhC, the cytochrome b subunit, called b556 in bacteria and b560 in mitochondria. SdhD (see TIGR02968) is called the hydrophobic membrane anchor subunit, although both SdhC and SdhD participate in anchoring the complex. In some bacteria, this cytochrome b subunit is replaced my a member of the cytochrome b558 family (see TIGR02046). [Energy metabolism, TCA cycle]


Pssm-ID: 274370  Cd Length: 120  Bit Score: 141.55  E-value: 1.26e-44
                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 15596778     7 SKRPVNLDLRTIKLPVTAYTSILHRISGVILFLGIAVLLFALDKSLSSEEGFEQVKACLTSPLAKLVIWGLLSALLYHLV 86
Cdd:TIGR02970   1 KQRPLSPHLQIYRFPITAILSILHRITGVLLFFGLPFLLWWLSLSLSSPESFATVHALLSSPLGKLILWGLLWALLYHLL 80

                          90       100       110       120
                  ....*....|....*....|....*....|....*....|
gi 15596778    87 AGVRHLVMDAGVGETLEGGKRGSKIVIAIAVVLIVLAGVW 126
Cdd:TIGR02970  81 AGIRHLLWDLGYGLELKSARISAWVVLVLSLVLTILAGIW 120
SQR_TypeC_SdhC cd03499
Succinate:quinone oxidoreductase (SQR) Type C subfamily, Succinate dehydrogenase C (SdhC) ...
 9-125 6.98e-43

Succinate:quinone oxidoreductase (SQR) Type C subfamily, Succinate dehydrogenase C (SdhC) subunit; composed of bacterial SdhC and eukaryotic large cytochrome b binding (CybL) proteins. SQR catalyzes the oxidation of succinate to fumarate coupled to the reduction of quinone to quinol. Members of this family reduce high potential quinones such as ubiquinone. SQR is also called succinate dehydrogenase or Complex II, and is part of the citric acid cycle and the aerobic respiratory chain. SQR is composed of a flavoprotein catalytic subunit, an iron-sulfur protein and one or two hydrophobic transmembrane subunits. Proteins in this subfamily are classified as Type C SQRs because they contain two transmembrane subunits and one heme group. The heme and quinone binding sites reside in the transmembrane subunits. The SdhC or CybL protein is one of the two transmembrane subunits of bacterial and eukaryotic SQRs. The two-electron oxidation of succinate in the flavoprotein active site is coupled to the two-electron reduction of quinone in the membrane anchor subunits via electron transport through FAD and three iron-sulfur centers. The reversible reduction of quinone is an essential feature of respiration, allowing transfer of electrons between respiratory complexes.


Pssm-ID: 239579  Cd Length: 117  Bit Score: 136.90  E-value: 6.98e-43
                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 15596778   9 RPVNLDLRTIKLPVTAYTSILHRISGVILFLGIAVLLFALDKSLSSEEGFEQVKACLTSPLAKLVIWGLLSALLYHLVAG 88
Cdd:cd03499   1 RPLSPHLTIYRPPLTAILSILHRITGVALFLGLPLLLWWLLASLSSPESFESVSALLGSWLGKLVLFGLTWALFYHLLNG 80

                        90       100       110
                ....*....|....*....|....*....|....*..
gi 15596778  89 VRHLVMDAGVGETLEGGKRGSKIVIAIAVVLIVLAGV 125
Cdd:cd03499  81 IRHLIWDLGKGLELKTVYKSGYAVLVLSVVLTVLLGI 117
sdhC PRK09487
succinate dehydrogenase cytochrome b556 subunit;
1-128 7.17e-43

succinate dehydrogenase cytochrome b556 subunit;


Pssm-ID: 181900  Cd Length: 129  Bit Score: 137.20  E-value: 7.17e-43
                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 15596778    1 MKKAVNSKRPVNLDLRTIKLPVTAYTSILHRISGVILFLGIAVLLFALDKSLSSEEGFEQVKACLTSPLAKLVIWGLLSA 80
Cdd:PRK09487   1 MIRNVKKQRPVNLDLQTIRFPITAIASILHRVSGVITFVAVGILLWLLGTSLSSPEGFEQAAAIMDSFFVKFIMWGILTA 80

                         90       100       110       120
                 ....*....|....*....|....*....|....*....|....*....
gi 15596778   81 LLYHLVAGVRHLVMDAG-VGETLEGGKRGSKIVIAIAVVLIVLAGVWVW 128
Cdd:PRK09487  81 LAYHVVVGIRHLLMDFGyLEETLEAGKRSAKISFVITVVLSLLAGVLVW 129
Sdh_cyt pfam01127
Succinate dehydrogenase/Fumarate reductase transmembrane subunit; This family includes a ...
 6-123 2.51e-26

Succinate dehydrogenase/Fumarate reductase transmembrane subunit; This family includes a transmembrane protein from both the Succinate dehydrogenase and Fumarate reductase complexes.


Pssm-ID: 426067  Cd Length: 122  Bit Score: 95.14  E-value: 2.51e-26
                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 15596778     6 NSKRPVNLDLRTIKLPVTAYTSILHRISGVILFLGIAVLLF---ALDKSLSSEEGFEQVKACLTSPLAKLVIWGLLSALL 82
Cdd:pfam01127   2 RKNRPLSPHLGLYRAHLTTWLSILHRITGVALAVLGLIFLLlwlLLLLSLLGPESYATVVAWLASPVKLILLLLLLLALF 81

                          90       100       110       120
                  ....*....|....*....|....*....|....*....|.
gi 15596778    83 YHLVAGVRHLVMDAGVGETLEGGKRGSKIVIAIAVVLIVLA 123
Cdd:pfam01127  82 YHAANGIRHLIWDVGFGLELKTVRKSGAAVLALSVVLVIVL 122
 
Name Accession Description Interval E-value
SdhC COG2009
Succinate dehydrogenase/fumarate reductase, cytochrome b subunit [Energy production and ...
 5-128 1.46e-50

Succinate dehydrogenase/fumarate reductase, cytochrome b subunit [Energy production and conversion];


Pssm-ID: 441612  Cd Length: 128  Bit Score: 156.48  E-value: 1.46e-50
                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 15596778   5 VNSKRPVNLDLRTIKLPVTAYTSILHRISGVILFLGIAVLLFALDKSLSSEEGFEQVKACLTSPLAKLVIWGLLSALLYH 84
Cdd:COG2009   3 VKKNRPLSPHLQIYRLPLTMIVSILHRITGVALFLGLPLLVWWLAASASSPEAFAAVQAFLGSPLGKLVLLGLTWALLYH 82

                        90       100       110       120
                ....*....|....*....|....*....|....*....|....
gi 15596778  85 LVAGVRHLVMDAGVGETLEGGKRGSKIVIAIAVVLIVLAGVWVW 128
Cdd:COG2009  83 LLAGIRHLLWDFGYGFELETARRSAWVVLVLSVVLTVLLGVVLW 126
succ_dehyd_cytB TIGR02970
succinate dehydrogenase, cytochrome b556 subunit; In E. coli and many other bacteria, two ...
 7-126 1.26e-44

succinate dehydrogenase, cytochrome b556 subunit; In E. coli and many other bacteria, two small, hydrophobic, mutually homologous subunits of succinate dehydrogenase, a TCA cycle enzyme, are SdhC and SdhD. This family is the SdhC, the cytochrome b subunit, called b556 in bacteria and b560 in mitochondria. SdhD (see TIGR02968) is called the hydrophobic membrane anchor subunit, although both SdhC and SdhD participate in anchoring the complex. In some bacteria, this cytochrome b subunit is replaced my a member of the cytochrome b558 family (see TIGR02046). [Energy metabolism, TCA cycle]


Pssm-ID: 274370  Cd Length: 120  Bit Score: 141.55  E-value: 1.26e-44
                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 15596778     7 SKRPVNLDLRTIKLPVTAYTSILHRISGVILFLGIAVLLFALDKSLSSEEGFEQVKACLTSPLAKLVIWGLLSALLYHLV 86
Cdd:TIGR02970   1 KQRPLSPHLQIYRFPITAILSILHRITGVLLFFGLPFLLWWLSLSLSSPESFATVHALLSSPLGKLILWGLLWALLYHLL 80

                          90       100       110       120
                  ....*....|....*....|....*....|....*....|
gi 15596778    87 AGVRHLVMDAGVGETLEGGKRGSKIVIAIAVVLIVLAGVW 126
Cdd:TIGR02970  81 AGIRHLLWDLGYGLELKSARISAWVVLVLSLVLTILAGIW 120
SQR_TypeC_SdhC cd03499
Succinate:quinone oxidoreductase (SQR) Type C subfamily, Succinate dehydrogenase C (SdhC) ...
 9-125 6.98e-43

Succinate:quinone oxidoreductase (SQR) Type C subfamily, Succinate dehydrogenase C (SdhC) subunit; composed of bacterial SdhC and eukaryotic large cytochrome b binding (CybL) proteins. SQR catalyzes the oxidation of succinate to fumarate coupled to the reduction of quinone to quinol. Members of this family reduce high potential quinones such as ubiquinone. SQR is also called succinate dehydrogenase or Complex II, and is part of the citric acid cycle and the aerobic respiratory chain. SQR is composed of a flavoprotein catalytic subunit, an iron-sulfur protein and one or two hydrophobic transmembrane subunits. Proteins in this subfamily are classified as Type C SQRs because they contain two transmembrane subunits and one heme group. The heme and quinone binding sites reside in the transmembrane subunits. The SdhC or CybL protein is one of the two transmembrane subunits of bacterial and eukaryotic SQRs. The two-electron oxidation of succinate in the flavoprotein active site is coupled to the two-electron reduction of quinone in the membrane anchor subunits via electron transport through FAD and three iron-sulfur centers. The reversible reduction of quinone is an essential feature of respiration, allowing transfer of electrons between respiratory complexes.


Pssm-ID: 239579  Cd Length: 117  Bit Score: 136.90  E-value: 6.98e-43
                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 15596778   9 RPVNLDLRTIKLPVTAYTSILHRISGVILFLGIAVLLFALDKSLSSEEGFEQVKACLTSPLAKLVIWGLLSALLYHLVAG 88
Cdd:cd03499   1 RPLSPHLTIYRPPLTAILSILHRITGVALFLGLPLLLWWLLASLSSPESFESVSALLGSWLGKLVLFGLTWALFYHLLNG 80

                        90       100       110
                ....*....|....*....|....*....|....*..
gi 15596778  89 VRHLVMDAGVGETLEGGKRGSKIVIAIAVVLIVLAGV 125
Cdd:cd03499  81 IRHLIWDLGKGLELKTVYKSGYAVLVLSVVLTVLLGI 117
sdhC PRK09487
succinate dehydrogenase cytochrome b556 subunit;
1-128 7.17e-43

succinate dehydrogenase cytochrome b556 subunit;


Pssm-ID: 181900  Cd Length: 129  Bit Score: 137.20  E-value: 7.17e-43
                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 15596778    1 MKKAVNSKRPVNLDLRTIKLPVTAYTSILHRISGVILFLGIAVLLFALDKSLSSEEGFEQVKACLTSPLAKLVIWGLLSA 80
Cdd:PRK09487   1 MIRNVKKQRPVNLDLQTIRFPITAIASILHRVSGVITFVAVGILLWLLGTSLSSPEGFEQAAAIMDSFFVKFIMWGILTA 80

                         90       100       110       120
                 ....*....|....*....|....*....|....*....|....*....
gi 15596778   81 LLYHLVAGVRHLVMDAG-VGETLEGGKRGSKIVIAIAVVLIVLAGVWVW 128
Cdd:PRK09487  81 LAYHVVVGIRHLLMDFGyLEETLEAGKRSAKISFVITVVLSLLAGVLVW 129
Sdh_cyt pfam01127
Succinate dehydrogenase/Fumarate reductase transmembrane subunit; This family includes a ...
 6-123 2.51e-26

Succinate dehydrogenase/Fumarate reductase transmembrane subunit; This family includes a transmembrane protein from both the Succinate dehydrogenase and Fumarate reductase complexes.


Pssm-ID: 426067  Cd Length: 122  Bit Score: 95.14  E-value: 2.51e-26
                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 15596778     6 NSKRPVNLDLRTIKLPVTAYTSILHRISGVILFLGIAVLLF---ALDKSLSSEEGFEQVKACLTSPLAKLVIWGLLSALL 82
Cdd:pfam01127   2 RKNRPLSPHLGLYRAHLTTWLSILHRITGVALAVLGLIFLLlwlLLLLSLLGPESYATVVAWLASPVKLILLLLLLLALF 81

                          90       100       110       120
                  ....*....|....*....|....*....|....*....|.
gi 15596778    83 YHLVAGVRHLVMDAGVGETLEGGKRGSKIVIAIAVVLIVLA 123
Cdd:pfam01127  82 YHAANGIRHLIWDVGFGLELKTVRKSGAAVLALSVVLVIVL 122
SQR_QFR_TM cd03493
Succinate:quinone oxidoreductase (SQR) and Quinol:fumarate reductase (QFR) family, ...
 28-125 1.79e-16

Succinate:quinone oxidoreductase (SQR) and Quinol:fumarate reductase (QFR) family, transmembrane subunits; SQR catalyzes the oxidation of succinate to fumarate coupled to the reduction of quinone to quinol, while QFR catalyzes the reverse reaction. SQR, also called succinate dehydrogenase or Complex II, is part of the citric acid cycle and the aerobic respiratory chain, while QFR is involved in anaerobic respiration with fumarate as the terminal electron acceptor. SQRs may reduce either high or low potential quinones while QFRs oxidize only low potential quinols. SQR and QFR share a common subunit arrangement, composed of a flavoprotein catalytic subunit, an iron-sulfur protein and one or two hydrophobic transmembrane subunits. The structural arrangement allows efficient electron transfer between the catalytic subunit, through iron-sulfur centers, and the transmembrane subunit(s) containing the electron donor/acceptor (quinol or quinone). The reversible reduction of quinone is an essential feature of respiration, allowing the transfer of electrons between respiratory complexes. SQRs and QFRs can be classified into five types (A-E) according to the number of their hydrophobic subunits and heme groups. This classification is consistent with the characteristics and phylogeny of the catalytic and iron-sulfur subunits. Type E proteins, e.g. non-classical archael SQRs, contain atypical transmembrane subunits and are not included in this hierarchy. The heme and quinone binding sites reside in the transmembrane subunits. Although succinate oxidation and fumarate reduction are carried out by separate enzymes in most organisms, some bifunctional enzymes that exhibit both SQR and QFR activities exist.


Pssm-ID: 239573  Cd Length: 98  Bit Score: 69.23  E-value: 1.79e-16
                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 15596778  28 ILHRISGVILFLGIAVLLFALDKSLSSEEGFEQVKACLTSPLAKLVIWGLLSALLYHLVAGVRHLVMDAGVGETLEGGKR 107
Cdd:cd03493   1 ILHRITGVALLLFLPLHLLGLLALLGGPYAFAEVVAFLSSPLGKLLYLLLLLALLYHALNGIRHLIWDYGKGLELKLRKA 80

                        90
                ....*....|....*...
gi 15596778 108 GSKIVIAIAVVLIVLAGV 125
Cdd:cd03493  81 LGYAVLALSVLLTVLLLF 98
SQR_TypeA_SdhC_like cd03501
Succinate:quinone oxidoreductase (SQR) Type A subfamily, Succinate dehydrogenase C (SdhC)-like ...
 29-125 2.93e-09

Succinate:quinone oxidoreductase (SQR) Type A subfamily, Succinate dehydrogenase C (SdhC)-like subunit; SQR catalyzes the oxidation of succinate to fumarate coupled to the reduction of quinone to quinol. Members of this subfamily reduce low potential quinones such as menaquinone and thermoplasmaquinone. SQR is also called succinate dehydrogenase or Complex II, and is part of the citric acid cycle and the aerobic respiratory chain. SQR is composed of a flavoprotein catalytic subunit, an iron-sulfur protein and one or two hydrophobic transmembrane subunits. Members of this subfamily are similar to the Thermoplasma acidophilum SQR and are classified as Type A because they contain two transmembrane subunits as well as two heme groups. Although there are no structures available for this subfamily, the presence of two hemes has been proven spectroscopically for T. acidophilum. The two membrane anchor subunits are similar to the SdhD and SdhC subunits of bacterial SQRs, which contain heme and quinone binding sites. The two-electron oxidation of succinate in the flavoprotein active site is coupled to the two-electron reduction of quinone in the membrane anchor subunits via electron transport through FAD and three iron-sulfur centers. The reversible reduction of quinone is an essential feature of respiration, allowing transfer of electrons between respiratory complexes.


Pssm-ID: 239581  Cd Length: 101  Bit Score: 50.73  E-value: 2.93e-09
                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 15596778  29 LHRISGVILFLGIAVLLFALDKSLSSEEGFEQVKACLTSPLAKLVIWGLLSALLYHLVAGVRHLVMDAGVGETLEgGKRG 108
Cdd:cd03501   6 LHRITGVVILFYLFLHVLDLSSLRRGPETYNAVIATYKSPIFKLGEFGLVAAVVFHALNGIRLILVDFGSGGPRY-QRQL 84

                        90
                ....*....|....*..
gi 15596778 109 SKIVIAIAVVLIVLAGV 125
Cdd:cd03501  85 FYIVLVLTVVLIVAAGY 101
PLN00127 PLN00127
succinate dehydrogenase (ubiquinone) cytochrome b subunit; Provisional
 6-126 8.33e-09

succinate dehydrogenase (ubiquinone) cytochrome b subunit; Provisional


Pssm-ID: 177738  Cd Length: 178  Bit Score: 51.03  E-value: 8.33e-09
                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 15596778    6 NSKRPVNLDLRTI-------KLPVTAYTSILHRISGVIL-----FLGIAVLLFALDKSLSSEEGFEQVKACLTSPLAKLV 73
Cdd:PLN00127  49 LEKRPLSPDVMDIdgksthyKFPVVALSSITNRVTGCVLsggaaGGGVLALVGGSEAVPATMEGFKSGGPLIVFPAKFAV 128

                         90       100       110       120       130
                 ....*....|....*....|....*....|....*....|....*....|....
gi 15596778   74 IWgllsALLYHLVAGVRHLVMDAGV-GETLEGGKRGSKIVIAIAVVLIVLAGVW 126
Cdd:PLN00127 129 SF----PFVYHTLGGLRHLVWDKTTeGLDNPSVEASSYGLFGASAALSAAAAVL 178
SdhD COG2142
Succinate dehydrogenase, hydrophobic anchor subunit [Energy production and conversion];
28-127 3.12e-07

Succinate dehydrogenase, hydrophobic anchor subunit [Energy production and conversion];


Pssm-ID: 441745  Cd Length: 124  Bit Score: 45.98  E-value: 3.12e-07
                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 15596778  28 ILHRISGVILFLGIAVLLFALdkSLSSEEGFEQVKACLTSPLAKLVIWGLLSALLYHLVAGVRHLVMDAGVGETLeggKR 107
Cdd:COG2142  24 LLQRVTAVALVVLVLWFLFFL--LSLPGADYAEVAAWFASPFWAILTLLFLLSALYHAWLGLRVVIEDYVHGTGL---RL 98

                        90       100
                ....*....|....*....|
gi 15596778 108 GSKIVIAIAVVLIVLAGVWV 127
Cdd:COG2142  99 ALLLLLTLALVALAAAGVFA 118
SQR_TypeA_SdhD_like cd03500
Succinate:quinone oxidoreductase (SQR) Type A subfamily, Succinate dehydrogenase D (SdhD)-like ...
 24-127 7.29e-04

Succinate:quinone oxidoreductase (SQR) Type A subfamily, Succinate dehydrogenase D (SdhD)-like subunit; SQR catalyzes the oxidation of succinate to fumarate coupled to the reduction of quinone to quinol. Members of this subfamily reduce low potential quinones such as menaquinone and thermoplasmaquinone. SQR is also called succinate dehydrogenase or Complex II, and is part of the citric acid cycle and the aerobic respiratory chain. SQR is composed of a flavoprotein catalytic subunit, an iron-sulfur protein and one or two hydrophobic transmembrane subunits. Members of this subfamily are similar to the Thermoplasma acidophilum SQR and are classified as Type A because they contain two transmembrane subunits as well as two heme groups. Although there are no structures available for this subfamily, the presence of two hemes has been proven spectroscopically for T. acidophilum. The two membrane anchor subunits are similar to the SdhD and SdhC subunits of bacterial SQRs, which contain heme and quinone binding sites. The two-electron oxidation of succinate in the flavoprotein active site is coupled to the two-electron reduction of quinone in the membrane anchor subunits via electron transport through FAD and three iron-sulfur centers. The reversible reduction of quinone is an essential feature of respiration, allowing transfer of electrons between respiratory complexes.


Pssm-ID: 239580  Cd Length: 106  Bit Score: 36.48  E-value: 7.29e-04
                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 15596778  24 AYTSILHRISGVIL--FLGIAVLLFALDKSLSSEeGFEQVKACLTSPLAKLVIWGLLSALLYHLVAGVRHLVMDAGVGET 101
Cdd:cd03500   2 SLAWLFQRITGVFLvfLLAGHFWVQHMDNGGDVI-DFAFVANRLASPLWKVWDLLLLVLALLHGGNGLRNILLDYVRRPR 80

                        90       100
                ....*....|....*....|....*.
gi 15596778 102 LeggKRGSKIVIAIAVVLIVLAGVWV 127
Cdd:cd03500  81 L---RRAVKGLLYVAGLLLIVLGTYV 103
QFR_TypeD_subunitD cd00547
Quinol:fumarate reductase (QFR) Type D subfamily, 13kD hydrophobic subunit D; QFR couples the ...
 35-127 1.61e-03

Quinol:fumarate reductase (QFR) Type D subfamily, 13kD hydrophobic subunit D; QFR couples the reduction of fumarate to succinate to the oxidation of quinol to quinone, the opposite reaction to that catalyzed by the related protein, succinate:quinine oxidoreductase (SQR). QFRs oxidize low potential quinols such as menaquinol and are involved in anaerobic respiration with fumarate as the terminal electron acceptor. SQR and QFR share a common subunit arrangement, composed of a flavoprotein catalytic subunit, an iron-sulfur protein and one or two hydrophobic transmembrane subunits. Members of this subfamily are classified as Type D as they contain two transmembrane subunits (C and D) and no heme groups. The structural arrangement allows efficient electron transfer between the catalytic subunit, through iron-sulfur centers, and the transmembrane subunit containing the electron donor (quinol). The quinone binding site resides in the transmembrane subunits.


Pssm-ID: 238307  Cd Length: 115  Bit Score: 35.78  E-value: 1.61e-03
                        10        20        30        40        50        60        70        80
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 15596778  35 VILFLGIAVLLFALDKSLSseegFEQVKACLTSPLAKLVIWGLLSALLYHLVAGVRHLVMDAGVgetlEGGKRGSKIVIA 114
Cdd:cd00547  28 LILLLGILLPLGLIPAALS----YDRIIAFAQSWIGKLFLLVLIILPMWHAMHRIHHGLHDLKI----HHVPAGKIIFYG 99

                        90
                ....*....|...
gi 15596778 115 IAVVLIVLAGVWV 127
Cdd:cd00547 100 LAALYSVLALFAV 112
 
Blast search parameters
Data Source: Precalculated data, version = cdd.v.3.21
Preset Options:Database: CDSEARCH/cdd   Low complexity filter: no  Composition Based Adjustment: yes   E-value threshold: 0.01

References:

  • Wang J et al. (2023), "The conserved domain database in 2023", Nucleic Acids Res.51(D)384-8.
  • Lu S et al. (2020), "The conserved domain database in 2020", Nucleic Acids Res.48(D)265-8.
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