Conserved Protein Domain Family

cd06529: S24_LexA-like 
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Peptidase S24 LexA-like proteins are involved in the SOS response leading to the repair of single-stranded DNA within the bacterial cell. This family includes: the lambda repressor CI/C2 family and related bacterial prophage repressor proteins; LexA (EC, the repressor of genes in the cellular SOS response to DNA damage; MucA and the related UmuD proteins, which are lesion-bypass DNA polymerases, induced in response to mitogenic DNA damage; RulA, a component of the rulAB locus that confers resistance to UV, and RuvA, which is a component of the RuvABC resolvasome that catalyzes the resolution of Holliday junctions that arise during genetic recombination and DNA repair. The LexA-like proteins contain two-domains: an N-terminal DNA binding domain and a C-terminal domain (CTD) that provides LexA dimerization as well as cleavage activity. They undergo autolysis, cleaving at an Ala-Gly or a Cys-Gly bond, separating the DNA-binding domain from the rest of the protein. In the presence of single-stranded DNA, the LexA, UmuD and MucA proteins interact with RecA, activating self cleavage, thus either derepressing transcription in the case of LexA or activating the lesion-bypass polymerase in the case of UmuD and MucA. The LexA proteins are serine proteases that carry out catalysis using a serine/lysine dyad instead of the prototypical serine/histidine/aspartic acid triad found in most serine proteases. LexA sequence homologs are found in almost all of the bacterial genomes sequenced to date, covering a large number of phyla, suggesting both, an ancient origin and a widespread distribution of lexA and the SOS response.
PSSM-Id: 119397
Aligned: 418 rows
Threshold Bit Score: 40.62
Created: 25-Jul-2008
Updated: 2-Oct-2020
Aligned Rows:
Catalytic site
Conserved site includes 2 residues -Click on image for an interactive view with Cn3D
Feature 1:Catalytic site [active site]
  • Comment:These serine proteases carry out catalysis using a serine/lysine dyad instead of the prototypical serine/histidine/aspartic acid triad found in most serine proteases.

Sequence Alignment
Format: Row Display: Color Bits: Type Selection:
Feature 1             #                                              #                        
2HNF_A     45 FWLEVEGNSMttptgsktsfpDGMLILVDpeqa----vepGDFCIARLGgdEFTFAKLIrds----gqvFLQPLNp---Q 113 Escherichia coli
YP_845986 143 FLIRVQGDAMlpt------vnQGDVALVDsdeaermrvlsGRIYLVVLPdgATAFRRLAlsggrdcprlVCLSDNt--aA 214 Syntrophobacter fu...
YP_248986 229 AMITMFNESMspv------inKKDLMFVDttck---qyagEGIYLFVMNn-ELYVRRLYqtps---gvlNAVAENe--rV 293 Haemophilus influe...
YP_389438 140 QVFRVDATSMepl------iaKGAFVCLDtqqk---siisGELYGVFIPyeGIAIRRVFldaq--nqrfILRSENp---A 205 Desulfovibrio desu...
YP_966496 152 VCVRVSQDSMapl------lhVGDYVIIDradcvvteqghGNIFLVNDPqdGPTIKRARiqstptstvlFCYCDNv---R 222 Desulfovibrio vulg...
YP_592466 148 RCMRVRGDSMapi------vdDGYIVAVDtserd-prklvESMVAVSDPesGCTIKWLRqagr---arfLLVPQHts-pR 216 Acidobacteria bact...
YP_333047 198 AVVRIEDDLMapt------fqRRDNVLVDmgyq---hkpgNGLYALRLEd-SIVVRRTQklss---gklRILCENe---N 261 Burkholderia pseud...
YP_972811 146 IAIAVGDDSMqps------lhPGDVVAVDtrdp---spadGQVFVVDYEg-ACLVRRVVrds----gawWLAAENa--lR 209 Acidovorax avenae ...
YP_972860 141 LAIRVRGCGMeps------iqAGDIVVVNtsdt---tlrdGQVFAINGFg-EVLLRRAQrdd----grwWISCDNpdqaR 206 Acidovorax avenae ...
CAJ73061  120 YLFHVKDDSMept------lkNGDVVIVDkknn---vldrDGLYLLRTEgaAAFIKRVQrlpg---gslHLLCDNa---T 184 Candidatus Kueneni...
Feature 1                            
2HNF_A    114 YPMIPCne------sCSVVGKVI 130 Escherichia coli
YP_845986 215 FRPFEFald---pgkPLRNHILG 234 Syntrophobacter fumaroxidans MPOB
YP_248986 294 GSSFEId-------dLSRLNVLG 309 Haemophilus influenzae 86-028NP
YP_389438 206 LPEQYLpl------gKHHSSIVG 222 Desulfovibrio desulfuricans subsp. desulfuricans str. G20
YP_966496 223 IPPSFIqipqdddnyLSHGVLGG 245 Desulfovibrio vulgaris subsp. vulgaris DP4
YP_592466 217 HNPIVLdp------kEEGWRIIG 233 Acidobacteria bacterium Ellin345
YP_333047 262 YPPDEIrpd----enEFDFEIVG 280 Burkholderia pseudomallei 1710b
YP_972811 210 FPRKQLt--------APSARLVG 224 Acidovorax avenae subsp. citrulli AAC00-1
YP_972860 207 YPRKAWa--------EPDCIPIG 221 Acidovorax avenae subsp. citrulli AAC00-1
CAJ73061  185 YKPIEAkta---qieNGDIVIVG 204 Candidatus Kuenenia stuttgartiensis

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