ID   LEXA_CLOBM              Reviewed;         201 AA.
AC   B1KS97;
DT   24-MAR-2009, integrated into UniProtKB/Swiss-Prot.
DT   29-APR-2008, sequence version 1.
DT   03-AUG-2022, entry version 81.
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=CLK_1175;
OS   Clostridium botulinum (strain Loch Maree / Type A3).
OC   Bacteria; Firmicutes; Clostridia; Eubacteriales; Clostridiaceae;
OC   Clostridium.
OX   NCBI_TaxID=498214;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=Loch Maree / Type A3;
RX   PubMed=18060065; DOI=10.1371/journal.pone.0001271;
RA   Smith T.J., Hill K.K., Foley B.T., Detter J.C., Munk A.C., Bruce D.C.,
RA   Doggett N.A., Smith L.A., Marks J.D., Xie G., Brettin T.S.;
RT   "Analysis of the neurotoxin complex genes in Clostridium botulinum A1-A4
RT   and B1 strains: BoNT/A3, /Ba4 and /B1 clusters are located within
RT   plasmids.";
RL   PLoS ONE 2:E1271-E1271(2007).
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; CP000962; ACA54894.1; -; Genomic_DNA.
DR   RefSeq; WP_003358834.1; NC_010520.1.
DR   AlphaFoldDB; B1KS97; -.
DR   SMR; B1KS97; -.
DR   MEROPS; S24.001; -.
DR   EnsemblBacteria; ACA54894; ACA54894; CLK_1175.
DR   KEGG; cbl:CLK_1175; -.
DR   HOGENOM; CLU_066192_45_1_9; -.
DR   OMA; HVWLLPH; -.
DR   Proteomes; UP000000722; 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; Repressor; SOS response; Transcription;
KW   Transcription regulation.
FT   CHAIN           1..201
FT                   /note="LexA repressor"
FT                   /id="PRO_1000089558"
FT   DNA_BIND        29..49
FT                   /note="H-T-H motif"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00015"
FT   ACT_SITE        125
FT                   /note="For autocatalytic cleavage activity"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00015"
FT   ACT_SITE        162
FT                   /note="For autocatalytic cleavage activity"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00015"
FT   SITE            89..90
FT                   /note="Cleavage; by autolysis"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00015"
SQ   SEQUENCE   201 AA;  22579 MW;  198BCD35EDC8383D CRC64;
     MNKSRIDKQN EVYNFIKLQI KEKGYPPSVR EICKAVGLSS TSSVHFHLKR LEKEGLIKRD
     SSKTRAIEIV DPTSKKEVIN VPIVGTITAG NPILAIENIE DVFPLPIDYV KNTKDLFMLK
     VSGESMIEAG ILDGDLAIIE KTDSANNGDI VVALIDNEAT LKRFFKESSY IRLQPENKSM
     KPIILENCKV LGRLVGIYRK Y