ID   LEXA_CLOD6              Reviewed;         211 AA.
AC   Q187P1;
DT   18-MAR-2008, integrated into UniProtKB/Swiss-Prot.
DT   21-SEP-2011, sequence version 2.
DT   03-AUG-2022, entry version 102.
DE   RecName: Full=LexA repressor {ECO:0000255|HAMAP-Rule:MF_00015};
DE            EC=3.4.21.88 {ECO:0000255|HAMAP-Rule:MF_00015};
GN   Name=lexA {ECO:0000255|HAMAP-Rule:MF_00015}; OrderedLocusNames=CD630_19310;
OS   Clostridioides difficile (strain 630) (Peptoclostridium difficile).
OC   Bacteria; Firmicutes; Clostridia; Eubacteriales; Peptostreptococcaceae;
OC   Clostridioides.
OX   NCBI_TaxID=272563;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=630;
RX   PubMed=16804543; DOI=10.1038/ng1830;
RA   Sebaihia M., Wren B.W., Mullany P., Fairweather N.F., Minton N.,
RA   Stabler R., Thomson N.R., Roberts A.P., Cerdeno-Tarraga A.M., Wang H.,
RA   Holden M.T.G., Wright A., Churcher C., Quail M.A., Baker S., Bason N.,
RA   Brooks K., Chillingworth T., Cronin A., Davis P., Dowd L., Fraser A.,
RA   Feltwell T., Hance Z., Holroyd S., Jagels K., Moule S., Mungall K.,
RA   Price C., Rabbinowitsch E., Sharp S., Simmonds M., Stevens K., Unwin L.,
RA   Whithead S., Dupuy B., Dougan G., Barrell B., Parkhill J.;
RT   "The multidrug-resistant human pathogen Clostridium difficile has a highly
RT   mobile, mosaic genome.";
RL   Nat. Genet. 38:779-786(2006).
CC   -!- FUNCTION: Represses a number of genes involved in the response to DNA
CC       damage (SOS response), including recA and lexA. In the presence of
CC       single-stranded DNA, RecA interacts with LexA causing an autocatalytic
CC       cleavage which disrupts the DNA-binding part of LexA, leading to
CC       derepression of the SOS regulon and eventually DNA repair.
CC       {ECO:0000255|HAMAP-Rule:MF_00015}.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=Hydrolysis of Ala-|-Gly bond in repressor LexA.; EC=3.4.21.88;
CC         Evidence={ECO:0000255|HAMAP-Rule:MF_00015};
CC   -!- SUBUNIT: Homodimer. {ECO:0000255|HAMAP-Rule:MF_00015}.
CC   -!- SIMILARITY: Belongs to the peptidase S24 family. {ECO:0000255|HAMAP-
CC       Rule:MF_00015}.
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DR   EMBL; AM180355; CAJ68806.2; -; Genomic_DNA.
DR   RefSeq; WP_009897067.1; NZ_CP010905.2.
DR   RefSeq; YP_001088437.2; NC_009089.1.
DR   AlphaFoldDB; Q187P1; -.
DR   SMR; Q187P1; -.
DR   STRING; 272563.CD630_19310; -.
DR   MEROPS; S24.001; -.
DR   EnsemblBacteria; CAJ68806; CAJ68806; CD630_19310.
DR   GeneID; 66354316; -.
DR   KEGG; cdf:CD630_19310; -.
DR   KEGG; pdc:CDIF630_02135; -.
DR   PATRIC; fig|272563.120.peg.2027; -.
DR   eggNOG; COG1974; Bacteria.
DR   OMA; HVWLLPH; -.
DR   PhylomeDB; Q187P1; -.
DR   BioCyc; PDIF272563:G12WB-2073-MON; -.
DR   Proteomes; UP000001978; Chromosome.
DR   GO; GO:0003677; F:DNA binding; IEA:UniProtKB-UniRule.
DR   GO; GO:0004252; F:serine-type endopeptidase activity; IEA:UniProtKB-UniRule.
DR   GO; GO:0006281; P:DNA repair; IEA:UniProtKB-UniRule.
DR   GO; GO:0006260; P:DNA replication; IEA:UniProtKB-UniRule.
DR   GO; GO:0045892; P:negative regulation of transcription, DNA-templated; IEA:UniProtKB-UniRule.
DR   GO; GO:0006508; P:proteolysis; IEA:InterPro.
DR   GO; GO:0009432; P:SOS response; IEA:UniProtKB-UniRule.
DR   CDD; cd00090; HTH_ARSR; 1.
DR   CDD; cd06529; S24_LexA-like; 1.
DR   Gene3D; 1.10.10.10; -; 1.
DR   HAMAP; MF_00015; LexA; 1.
DR   InterPro; IPR011991; ArsR-like_HTH.
DR   InterPro; IPR006200; LexA.
DR   InterPro; IPR039418; LexA-like.
DR   InterPro; IPR036286; LexA/Signal_pep-like_sf.
DR   InterPro; IPR006199; LexA_DNA-bd_dom.
DR   InterPro; IPR006197; Peptidase_S24_LexA.
DR   InterPro; IPR015927; Peptidase_S24_S26A/B/C.
DR   InterPro; IPR036388; WH-like_DNA-bd_sf.
DR   InterPro; IPR036390; WH_DNA-bd_sf.
DR   Pfam; PF01726; LexA_DNA_bind; 1.
DR   Pfam; PF00717; Peptidase_S24; 1.
DR   PRINTS; PR00726; LEXASERPTASE.
DR   SUPFAM; SSF46785; SSF46785; 1.
DR   SUPFAM; SSF51306; SSF51306; 1.
DR   TIGRFAMs; TIGR00498; lexA; 1.
PE   3: Inferred from homology;
KW   Autocatalytic cleavage; DNA damage; DNA repair; DNA replication;
KW   DNA-binding; Hydrolase; Reference proteome; Repressor; SOS response;
KW   Transcription; Transcription regulation.
FT   CHAIN           1..211
FT                   /note="LexA repressor"
FT                   /id="PRO_0000322724"
FT   DNA_BIND        29..49
FT                   /note="H-T-H motif"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00015"
FT   ACT_SITE        131
FT                   /note="For autocatalytic cleavage activity"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00015"
FT   ACT_SITE        169
FT                   /note="For autocatalytic cleavage activity"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00015"
FT   SITE            96..97
FT                   /note="Cleavage; by autolysis"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00015"
SQ   SEQUENCE   211 AA;  23473 MW;  8571BD9BB5103F76 CRC64;
     MYLDLTEKQV LILEFIKSQI ILKGYPPAVR EICTAVGLRS TSTVHSHLNK LEKLGYIRKD
     PTKPRAIEVL ERSKVNDVSG ANQEIIELPL VGQITAGEPI LAQQNIEEYI PFPASLVKGS
     NNFVLRVKGE SMINAGILDE DYVVVDKKNT ALNSQIVVAL INGESATVKR FFKEGNLIRL
     QPENDFMEPI MLNDSEVEIV GIVTGVFRVI K