Arsenate Reductase (ArsC) family, ArsC subfamily; arsenic reductases similar to that encoded by arsC on the R733 plasmid of Escherichia coli. E. coli ArsC catalyzes the reduction of arsenate [As(V)] to arsenite [As(III)], the first step in the detoxification of arsenic, using reducing equivalents derived from glutathione (GSH) via glutaredoxin (GRX). ArsC contains a single catalytic cysteine, within a thioredoxin fold, that forms a covalent thiolate-As(V) intermediate, which is reduced by GRX through a mixed GSH-arsenate intermediate. This family of predominantly bacterial enzymes is unrelated to two other families of arsenate reductases which show similarity to low-molecular-weight acid phosphatases and phosphotyrosyl phosphatases.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 564862340   6 TIYHNPRCSTSRKTLELLRDNGFELSIVEYLKTPPSRAELVKMIRDAGIDVRTAVRKRESLYGELNLA--EASDEQLLDA 83
Cdd:cd03034    2 TIYHNPRCSKSRNALALLEEAGIEPEIVEYLKTPPTAAELRELLAKLGISPRDLLRTKEAPYKELGLAdpELSDEELIDA 81

                         90       100       110
                 ....*....|....*....|....*....|.
gi 564862340  84 MIEHPILIERPFVVTPKGTRLARPIDAVREI 114
Cdd:cd03034   82 MAAHPILIERPIVVTGDGAVLGRPPEAVLEL 112

Arsenate Reductase (ArsC) family, ArsC subfamily; arsenic reductases similar to that encoded by arsC on the R733 plasmid of Escherichia coli. E. coli ArsC catalyzes the reduction of arsenate [As(V)] to arsenite [As(III)], the first step in the detoxification of arsenic, using reducing equivalents derived from glutathione (GSH) via glutaredoxin (GRX). ArsC contains a single catalytic cysteine, within a thioredoxin fold, that forms a covalent thiolate-As(V) intermediate, which is reduced by GRX through a mixed GSH-arsenate intermediate. This family of predominantly bacterial enzymes is unrelated to two other families of arsenate reductases which show similarity to low-molecular-weight acid phosphatases and phosphotyrosyl phosphatases.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 564862340   6 TIYHNPRCSTSRKTLELLRDNGFELSIVEYLKTPPSRAELVKMIRDAGIDVRTAVRKRESLYGELNLA--EASDEQLLDA 83
Cdd:cd03034    2 TIYHNPRCSKSRNALALLEEAGIEPEIVEYLKTPPTAAELRELLAKLGISPRDLLRTKEAPYKELGLAdpELSDEELIDA 81

                         90       100       110
                 ....*....|....*....|....*....|.
gi 564862340  84 MIEHPILIERPFVVTPKGTRLARPIDAVREI 114
Cdd:cd03034   82 MAAHPILIERPIVVTGDGAVLGRPPEAVLEL 112

arsenate reductase (glutaredoxin); This model describes a distinct clade, including ArsC itself, of the broader ArsC family described by Pfam pfam03960. This clade is almost completely restricted to the Proteobacteria. An anion-translocating ATPase has been identified as the product of the arsenical resistance operon of resistance plasmid R773. When expressed in Escherichia coli this ATP-driven oxyanion pump catalyses extrusion of the oxyanions arsenite, antimonite and arsenate. The pump is composed of two polypeptides, the products of the arsA and arsB genes. The pump alone produces resistance to arsenite and antimonite. This protein, ArsC, catalyzes the reduction of arsenate to arsenite, and thus extends resistance to include arsenate. [Cellular processes, Detoxification]

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 564862340    6 TIYHNPRCSTSRKTLELLRDNGFELSIVEYLKTPPSRAELVKMIRDAGIDV-RTAVRKRESLYGELNLA--EASDEQLLD 82
Cdd:TIGR00014   2 TIYHNPRCSKSRNTLALLEDKGIEPEVVKYLKNPPTKSELEAIFAKLGLTVaREMIRTKEALYKELGLSdpNLSDQELLD 81

                          90       100       110
                  ....*....|....*....|....*....|...
gi 564862340   83 AMIEHPILIERPFVVTPKGTRLARPIDAVREIL 115
Cdd:TIGR00014  82 AMVAHPILLERPIVVAGDGARIGRPPENVLDIL 114

ArsC family; This family is related to glutaredoxins pfam00462.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 564862340    8 YHNPRCSTSRKTLELLRDNGFELSIVEYLKTPPSRAELVKMIRDAGIDVRTAVRKRESLYGELNLA--EASDEQLLDAMI 85
Cdd:pfam03960   1 YGSPNCSTCRKALAWLEEHGIEYQEIDYLETPPSKEELKDILAKLGDGVEALLNTRGTTYRELNLDkeDLSEDELLELIL 80

                          90       100
                  ....*....|....*....|....*....
gi 564862340   86 EHPILIERPFVVTPKGTRLARPIDAVREI 114
Cdd:pfam03960  81 EHPSLIRRPIVVDGGKLLVGFNEEEIRAF 109

Arsenate Reductase (ArsC) family, ArsC subfamily; arsenic reductases similar to that encoded by arsC on the R733 plasmid of Escherichia coli. E. coli ArsC catalyzes the reduction of arsenate [As(V)] to arsenite [As(III)], the first step in the detoxification of arsenic, using reducing equivalents derived from glutathione (GSH) via glutaredoxin (GRX). ArsC contains a single catalytic cysteine, within a thioredoxin fold, that forms a covalent thiolate-As(V) intermediate, which is reduced by GRX through a mixed GSH-arsenate intermediate. This family of predominantly bacterial enzymes is unrelated to two other families of arsenate reductases which show similarity to low-molecular-weight acid phosphatases and phosphotyrosyl phosphatases.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 564862340   6 TIYHNPRCSTSRKTLELLRDNGFELSIVEYLKTPPSRAELVKMIRDAGIDVRTAVRKRESLYGELNLA--EASDEQLLDA 83
Cdd:cd03034    2 TIYHNPRCSKSRNALALLEEAGIEPEIVEYLKTPPTAAELRELLAKLGISPRDLLRTKEAPYKELGLAdpELSDEELIDA 81

                         90       100       110
                 ....*....|....*....|....*....|.
gi 564862340  84 MIEHPILIERPFVVTPKGTRLARPIDAVREI 114
Cdd:cd03034   82 MAAHPILIERPIVVTGDGAVLGRPPEAVLEL 112

arsenate reductase (glutaredoxin); This model describes a distinct clade, including ArsC itself, of the broader ArsC family described by Pfam pfam03960. This clade is almost completely restricted to the Proteobacteria. An anion-translocating ATPase has been identified as the product of the arsenical resistance operon of resistance plasmid R773. When expressed in Escherichia coli this ATP-driven oxyanion pump catalyses extrusion of the oxyanions arsenite, antimonite and arsenate. The pump is composed of two polypeptides, the products of the arsA and arsB genes. The pump alone produces resistance to arsenite and antimonite. This protein, ArsC, catalyzes the reduction of arsenate to arsenite, and thus extends resistance to include arsenate. [Cellular processes, Detoxification]

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 564862340    6 TIYHNPRCSTSRKTLELLRDNGFELSIVEYLKTPPSRAELVKMIRDAGIDV-RTAVRKRESLYGELNLA--EASDEQLLD 82
Cdd:TIGR00014   2 TIYHNPRCSKSRNTLALLEDKGIEPEVVKYLKNPPTKSELEAIFAKLGLTVaREMIRTKEALYKELGLSdpNLSDQELLD 81

                          90       100       110
                  ....*....|....*....|....*....|...
gi 564862340   83 AMIEHPILIERPFVVTPKGTRLARPIDAVREIL 115
Cdd:TIGR00014  82 AMVAHPILLERPIVVAGDGARIGRPPENVLDIL 114

Arsenate Reductase (ArsC) family; composed of TRX-fold arsenic reductases and similar proteins including the transcriptional regulator, Spx. ArsC catalyzes the reduction of arsenate [As(V)] to arsenite [As(III)], using reducing equivalents derived from glutathione (GSH) via glutaredoxin (GRX), through a single catalytic cysteine. This family of predominantly bacterial enzymes is unrelated to two other families of arsenate reductases which show similarity to low-molecular-weight acid phosphatases and phosphotyrosyl phosphatases. Spx is a general regulator that exerts negative and positive control over transcription initiation by binding to the C-terminal domain of the alpha subunit of RNA polymerase.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 564862340   6 TIYHNPRCSTSRKTLELLRDNGFELSIVEYLKTPPSRAELVKMIRDAGIDVRTAVRKRESLYGELNLA---EASDEQLLD 82
Cdd:cd02977    2 TIYGNPNCSTSRKALAWLEEHGIEYEFIDYLKEPPTKEELKELLAKLGLGVEDLFNTRGTPYRKLGLAdkdELSDEEALE 81

                         90       100
                 ....*....|....*....|....
gi 564862340  83 AMIEHPILIERPFVVTPKGTRLAR 106
Cdd:cd02977   82 LMAEHPKLIKRPIVVDGDRLLVGF 105

Arsenate Reductase (ArsC) family, unknown subfamily; uncharacterized proteins containing a CXXC motif with similarity to thioredoxin (TRX)-fold arsenic reductases, ArsC. Proteins containing a redox active CXXC motif like TRX and glutaredoxin (GRX) function as protein disulfide oxidoreductases, altering the redox state of target proteins via the reversible oxidation of the active site dithiol. ArsC catalyzes the reduction of arsenate [As(V)] to arsenite [As(III)], using reducing equivalents derived from glutathione via GRX, through a single catalytic cysteine.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 564862340   6 TIYHNPRCSTSRKTLELLRDNGFELSIVEYLKTPPSRAELVKMIRDAGIDVRTAVRKRESLYGELNLAE----ASDEQLL 81
Cdd:cd03036    2 KFYEYPKCSTCRKAKKWLDEHGVDYTAIDIVEEPPSKEELKKWLEKSGLPLKKFFNTSGKSYRELGLKDklpsLSEEEAL 81

                         90
                 ....*....|....*...
gi 564862340  82 DAMIEHPILIERPFVVTP 99
Cdd:cd03036   82 ELLSSDGMLIKRPFVVDD 99

Arsenate Reductase (ArsC) family, 15kD protein subfamily; composed of proteins of unknown function with similarity to thioredoxin-fold arsenic reductases, ArsC. It is encoded by an ORF present in a gene cluster associated with nitrogen fixation that also encodes dinitrogenase reductase ADP-ribosyltransferase (DRAT) and dinitrogenase reductase activating glycohydrolase (DRAG). ArsC catalyzes the reduction of arsenate [As(V)] to arsenite [As(III)], using reducing equivalents derived from glutathione via glutaredoxin, through a single catalytic cysteine.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 564862340   6 TIYHNPRCSTSRKTLELLRDNGFELSIVEYLKTPPSRAELVKMIRDAGIDV---RTAVRKReslYGELNLAEASDEQLLD 82
Cdd:cd03033    3 IFYEKPGCANNARQKALLEAAGHEVEVRDLLTEPWTAETLRPFFGDLPVAEwfnPAAPRVK---SGEVVPEALDEEEALA 79

                         90
                 ....*....|..
gi 564862340  83 AMIEHPILIERP 94
Cdd:cd03033   80 LMIADPLLIRRP 91

Arsenate Reductase (ArsC) family, Spx subfamily; Spx is a unique RNA polymerase (RNAP)-binding protein present in bacilli and some mollicutes. It inhibits transcription by binding to the C-terminal domain of the alpha subunit of RNAP, disrupting complex formation between RNAP and certain transcriptional activator proteins like ResD and ComA. In response to oxidative stress, Spx can also activate transcription, making it a general regulator that exerts both positive and negative control over transcription initiation. Spx has been shown to exert redox-sensitive transcriptional control over genes like trxA (TRX) and trxB (TRX reductase), genes that function in thiol homeostasis. This redox-sensitive activity is dependent on the presence of a CXXC motif, present in some members of the Spx subfamily, that acts as a thiol/disulfide switch. Spx has also been shown to repress genes in a sulfate-dependent manner independent of the presence of the CXXC motif.

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 564862340   6 TIYHNPRCSTSRKTLELLRDNGFELSIVEYLKTPPSRAELVKMIR--DAGIDvrTAVRKRESLYGELN--LAEASDEQLL 81
Cdd:cd03032    3 KLYTSPSCSSCRKAKQWLEEHQIPFEERNLFKQPLTKEELKEILSltENGVE--DIISTRSKAFKNLNidIDELSLSELI 80

                         90
                 ....*....|....*.
gi 564862340  82 DAMIEHPILIERPFVV 97
Cdd:cd03032   81 RLISEHPSLLRRPIII 96