Sortase domain found in subfamily 1 of the class D family of sortases; Class D sortases are cysteine transpeptidases distributed in Gram-positive bacteria (mainly present in Firmicutes). The prototypical subfamily 1 of class D sortase from Bacillus anthracis (named Ba-SrtC) covalently attaches proteins bearing a noncanonical LPNTA sorting signal, such as the BasH and BasI proteins, to the peptidoglycan of the cell wall that facilitate sporulation. BasH is exclusively anchored to the forespore cell wall envelope, while BasI is attached to the diaminopimelic acid moiety of the peptidoglycan of predivisional cells. Ba-SrtC lacks the N-terminal signal peptide and membrane anchor. The family also includes many class D sortase homologs from Gram-negative bacteria, but the functions of these enzymes are unknown.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1066926494  72 GEKVAMLNIPKIKKKFSIYWGADDMTLKKGVGMFVSdlTTTPSGGGHTVLSGHRDTVFTDLEELKEKDTLVLEYDNKTYT 151
Cdd:cd05828     1 GEPVARLSIPRLGLDLPVLEGTSGEALAFGPGHLPG--SALPGEGGNVVIAGHRDTHFRFLKDLKVGDEITLETSGGTYT 78

                          90       100       110       120
                  ....*....|....*....|....*....|....*....|....*....
gi 1066926494 152 YEIQKTWITHADDRTVIIKKEEPILTLTTCYPFDYIGDAPDRYIIEAKL 200
Cdd:cd05828    79 YRVTETRIVDADDTSVLLPTDEETLTLVTCYPFDALGSAPLRYVVYAEL 127

Sortase domain; The founder member of this family is S. aureus sortase, a transpeptidase that attaches surface proteins by the threonine of an LPXTG motif to the cell wall.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1066926494  78 LNIPKIKKKFSIYWGADDMTLKKGVGMFvsDLTTTPSGGGHTVLSGHR---DTVFTDLEELKEKDTLVLEYDNKTYTYEI 154
Cdd:pfam04203   1 LEIPAIGVDAPVLEGTSGEVLKYGVGHY--DGTAMPGEKGNFVLAGHRmggGTVFARLDKLKKGDKIYVTTDGKTYTYRV 78

                          90       100       110       120
                  ....*....|....*....|....*....|....*....|....*..
gi 1066926494 155 QKTWITHADDRTVI-IKKEEPILTLTTCYPfdyiGDAPDRYIIEAKL 200
Cdd:pfam04203  79 TSVEVVDPDDVSVLdPTPGDPILTLITCTP----PSYTKRLVVYAKL 121

sortase, marine proteobacterial type; Members of this protein family are sortase enzymes, cysteine transpeptidases involved in protein sorting activities. Members of this family tend to be found in proteobacteria, rather than in Gram-positive bacteria where sortases attach proteins to the Gram-positive cell wall or participate in pilin cross-linking. Many species with this sortase appear to contain a signal target sequence, a protein with a Vault protein inter-alpha-trypsin domain (pfam08487) and a von Willebrand factor type A domain (pfam00092), encoded by an adjacent gene. These sortases are designated subfamily 6 according to Comfort and Clubb (2004).

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1066926494  75 VAMLNIPKIKKKFSIYWGADDMTLKKGVGMFVSdlTTTPSGGGHTVLSGHRDTVFTDLEELKEKDTLVLE-YDNKTYTYE 153
Cdd:TIGR03784  51 VAKLSAPRLGASLYVLAGASGRNLAFGPGHMLA--TAQPGAQGNSVIAGHRDTHFAFLQELRPGDVIRLQtPDGQWQSYQ 128

                          90       100       110       120
                  ....*....|....*....|....*....|....*....|....*.
gi 1066926494 154 IQKTWITHADDRTVIIKKEEPILTLTTCYPFDYIG-DAPDRYIIEA 198
Cdd:TIGR03784 129 VTATRVVDESETGLDLPADDSQLVLITCYPFDALGsGGPLRYVVEA 174

Sortase domain found in subfamily 1 of the class D family of sortases; Class D sortases are cysteine transpeptidases distributed in Gram-positive bacteria (mainly present in Firmicutes). The prototypical subfamily 1 of class D sortase from Bacillus anthracis (named Ba-SrtC) covalently attaches proteins bearing a noncanonical LPNTA sorting signal, such as the BasH and BasI proteins, to the peptidoglycan of the cell wall that facilitate sporulation. BasH is exclusively anchored to the forespore cell wall envelope, while BasI is attached to the diaminopimelic acid moiety of the peptidoglycan of predivisional cells. Ba-SrtC lacks the N-terminal signal peptide and membrane anchor. The family also includes many class D sortase homologs from Gram-negative bacteria, but the functions of these enzymes are unknown.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1066926494  72 GEKVAMLNIPKIKKKFSIYWGADDMTLKKGVGMFVSdlTTTPSGGGHTVLSGHRDTVFTDLEELKEKDTLVLEYDNKTYT 151
Cdd:cd05828     1 GEPVARLSIPRLGLDLPVLEGTSGEALAFGPGHLPG--SALPGEGGNVVIAGHRDTHFRFLKDLKVGDEITLETSGGTYT 78

                          90       100       110       120
                  ....*....|....*....|....*....|....*....|....*....
gi 1066926494 152 YEIQKTWITHADDRTVIIKKEEPILTLTTCYPFDYIGDAPDRYIIEAKL 200
Cdd:cd05828    79 YRVTETRIVDADDTSVLLPTDEETLTLVTCYPFDALGSAPLRYVVYAEL 127

Sortase domain; The founder member of this family is S. aureus sortase, a transpeptidase that attaches surface proteins by the threonine of an LPXTG motif to the cell wall.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1066926494  78 LNIPKIKKKFSIYWGADDMTLKKGVGMFvsDLTTTPSGGGHTVLSGHR---DTVFTDLEELKEKDTLVLEYDNKTYTYEI 154
Cdd:pfam04203   1 LEIPAIGVDAPVLEGTSGEVLKYGVGHY--DGTAMPGEKGNFVLAGHRmggGTVFARLDKLKKGDKIYVTTDGKTYTYRV 78

                          90       100       110       120
                  ....*....|....*....|....*....|....*....|....*..
gi 1066926494 155 QKTWITHADDRTVI-IKKEEPILTLTTCYPfdyiGDAPDRYIIEAKL 200
Cdd:pfam04203  79 TSVEVVDPDDVSVLdPTPGDPILTLITCTP----PSYTKRLVVYAKL 121

Sortase domain found in class C sortases; Class C sortases are membrane-bound cysteine transpeptidases broadly distributed in Gram-positive bacteria (mainly present in Firmicutes and Actinobacteria). They function as pilin polymerases responsible for the assembly of pili, which are multi-subunit hair-like fibres that extend from the cell surface to promote microbial adhesion and biofilm formation. First, one or more class C sortases form the long thin shaft of the pilus through linking together pilin subunits via isopeptide bonds. The base of the pilus is then anchored to the cell wall by a housekeeping sortase or, in some cases, the class C sortase itself. Depending upon the organism both the number and type of sortase enzymes involved varies, and in some cases, accessory factors appear to be needed. In three-component spaA pilus from Corynebacterium diphtheriae, the prototypical class C sortase (named Cd-SrtA) catalyzes polymerization of the SpaA-type pilus, consisting of the shaft pilin SpaA, tip pilin SpaC and minor pilin SpaB. The pilus shaft is then attached to the cell wall by a housekeeping class E sortase, Cd-SrtF. In the absence of Cd-SrtF, Cd-SrtA attaches the pilus to the cell wall, albeit at a reduced rate. Cd-SrtA can recognize two distinct sorting signals (LPLTG in SpaA and SpaC, and LAFTG in SpaB) and it can employ lysine residues that originate from different proteins (either Lys190 within the pilin motif of SpaA or Lys139 in SpaB). However, Cd-SrtA cannot be able to polymerize the major pilin subunit SpaH, even though it contains LPLTG motif. In two-component pili of prototypical Bacillus cereus, the class C sortase (named Bc-SrtD) cleaves related sorting signals within a major pilin protein BcpA (LPVTG) and a minor tip pilin BcpB (IPNTG), and catalyzes a transpeptidation that joins the threonine residues in each signal to the side-chain of Lys162 in BcpA (located within a pilin motif). Unlike the SpaA pilus in C. diphtheriae, in B. cereus Bc-SrtD is unable to covalently attach the pilus to the cell wall without the help of the housekeeping sortase.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1066926494  73 EKVAMLNIPKIKKKFSIYWGADDMTLKKGVGMFVSdlTTTPSGGG--HTVLSGHR----DTVFTDLEELKEKDTLVLEYD 146
Cdd:cd05827     2 GVIGYLEIPKIDVDLPIYHGTSEEVLAKGAGHLEG--TSLPVGGKgtHSVIAGHRglpnATLFTDLDKLKKGDKFYITVL 79

                          90       100       110       120       130
                  ....*....|....*....|....*....|....*....|....*....|....
gi 1066926494 147 NKTYTYEI-QKTWITHADDRTVIIKKEEPILTLTTCYPfdyIGDAPDRYIIEAK 199
Cdd:cd05827    80 GETLAYKVdDIKVILPDDTDKLKIQPGKDLVTLLTCTP---YGINTHRLLVTGE 130

Sortase domain found in subfamily 2 of the class D family of sortases; Class D sortases are cysteine transpeptidases distributed in Gram-positive bacteria (mainly present in Firmicutes). They anchor surface proteins bearing a cell wall sorting signal to peptidoglycans of the bacterial cell wall envelope, which is responsible for spore formation under anaerobic conditions. This involves a transpeptidation reaction in which the surface protein substrate is cleaved at the cell wall sorting signal and covalently linked to peptidoglycan for display on the bacterial surface. The prototypical subfamily 2 of class D sortase from Clostridium perfringens (named Cp-SrtD) recognizes the LPQTGS signal motif for transpeptidation. Its catalytic activity is in a metal cation- and temperature- dependent manner. The presence of magnesium appears to enhance Cp-SrtD catalysis towards the LPQTGS signal motif.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1066926494  72 GEKVAMLNIPKIKKKFSIYWGADDMTLKKGVGMFVSdlTTTPSGGGHTVLSGHR----DTVFTDLEELKEKDTLVLEYDN 147
Cdd:cd06166     1 GGVIGILEIPKIDLKLPILEGATEENLKYGVGHFEG--TAMPGEGGNFAIAGHRsytyGRFFNRLDELKIGDEIIVTTKN 78

                          90       100       110       120       130
                  ....*....|....*....|....*....|....*....|....*....|...
gi 1066926494 148 KTYTYEIQKTWITHADDRTVIIK-KEEPILTLTTCYPfdyiGDAPDRYIIEAK 199
Cdd:cd06166    79 GTYTYKVTEIFIVEPTDVSVLDPtEGKKEITLITCTP----INPTHRLIVKAE 127

sortase, marine proteobacterial type; Members of this protein family are sortase enzymes, cysteine transpeptidases involved in protein sorting activities. Members of this family tend to be found in proteobacteria, rather than in Gram-positive bacteria where sortases attach proteins to the Gram-positive cell wall or participate in pilin cross-linking. Many species with this sortase appear to contain a signal target sequence, a protein with a Vault protein inter-alpha-trypsin domain (pfam08487) and a von Willebrand factor type A domain (pfam00092), encoded by an adjacent gene. These sortases are designated subfamily 6 according to Comfort and Clubb (2004).

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1066926494  75 VAMLNIPKIKKKFSIYWGADDMTLKKGVGMFVSdlTTTPSGGGHTVLSGHRDTVFTDLEELKEKDTLVLE-YDNKTYTYE 153
Cdd:TIGR03784  51 VAKLSAPRLGASLYVLAGASGRNLAFGPGHMLA--TAQPGAQGNSVIAGHRDTHFAFLQELRPGDVIRLQtPDGQWQSYQ 128

                          90       100       110       120
                  ....*....|....*....|....*....|....*....|....*.
gi 1066926494 154 IQKTWITHADDRTVIIKKEEPILTLTTCYPFDYIG-DAPDRYIIEA 198
Cdd:TIGR03784 129 VTATRVVDESETGLDLPADDSQLVLITCYPFDALGsGGPLRYVVEA 174

Sortase domain found in class A sortases; Class A sortases are membrane-bound cysteine transpeptidases distributed in Gram-positive bacteria (mainly present in Firmicutes). They perform a housekeeping role in the cell as members of this group are capable of anchoring a large number of functionally distinct surface proteins containing a cell wall sorting signal to an amino group located on the bacterial cell wall. They do so by catalyzing a transpeptidation reaction in which the surface protein substrate is cleaved at a conserved cell wall-sorting signal (Class A sortases recognize a canonical LPXTG motif, X can be any amino acid), and covalently linked to peptidoglycan for display on the bacterial surface. The prototypical sortase A protein from Staphylococcus aureus (named Sa-SrtA) cleaves the amide bond between threonine and glycine residues of the canonical LPXTG motif in a wide range of protein substrates with diverse functions that can promote bacterial adhesion, nutrient acquisition, host cell invasion, and immune evasion. Next, it catalyzes a transpeptidation reaction by which the proteins are covalently linked to the peptidoglycan precursor lipid II. SrtA is therefore affects the ability of a pathogen to establish successful infection. SrtA contains an N-terminal hydrophobic segment, a linker region and an extra-cellular C-terminal catalytic domain. The hydrophobic segment functions as both a signal peptide for secretion and a stop-transfer signal for membrane anchoring. The catalytic domain contains the catalytic TLXTC signature sequence where X is usually a valine, isoleucine or a threonine. The gene encoding SrtA is generally not located in the same gene cluster as its substrates while the gene encoding SrtB is usually clustered in the same locus as its substrate.

                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 1066926494  75 VAMLNIPKIKKKFSIYWGADDMTLKKGVGMFVSDLTTtpsGGGHTVLSGHR----DTVFTDLEELKEKDTLVLEYDNKTY 150
Cdd:cd06165     4 IGAIAIPSVGINLPIFKGLSNENLLVGAGTMKPNQKM---GKGNYVLAGHNmgdgGLLFSPLQNLKKGDKIYLTDLKKVY 80

                          90       100       110       120       130
                  ....*....|....*....|....*....|....*....|....*....|
gi 1066926494 151 TYEIQKTWITHADDRTVI-IKKEEPILTLTTCypfDYIGDAPDRYIIEAK 199
Cdd:cd06165    81 EYKVTSKKVVDPTDVDVLdDTKGKPLLTLITC---DDPTDTTKRIVVQGE 127