ID   LEXA_CARHZ              Reviewed;         204 AA.
AC   Q3ACC4;
DT   18-MAR-2008, integrated into UniProtKB/Swiss-Prot.
DT   22-NOV-2005, sequence version 1.
DT   03-AUG-2022, entry version 100.
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=CHY_1378;
OS   Carboxydothermus hydrogenoformans (strain ATCC BAA-161 / DSM 6008 /
OS   Z-2901).
OC   Bacteria; Firmicutes; Clostridia; Thermoanaerobacterales;
OC   Thermoanaerobacteraceae; Carboxydothermus.
OX   NCBI_TaxID=246194;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=ATCC BAA-161 / DSM 6008 / Z-2901;
RX   PubMed=16311624; DOI=10.1371/journal.pgen.0010065;
RA   Wu M., Ren Q., Durkin A.S., Daugherty S.C., Brinkac L.M., Dodson R.J.,
RA   Madupu R., Sullivan S.A., Kolonay J.F., Nelson W.C., Tallon L.J.,
RA   Jones K.M., Ulrich L.E., Gonzalez J.M., Zhulin I.B., Robb F.T., Eisen J.A.;
RT   "Life in hot carbon monoxide: the complete genome sequence of
RT   Carboxydothermus hydrogenoformans Z-2901.";
RL   PLoS Genet. 1:563-574(2005).
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; CP000141; ABB16235.1; -; Genomic_DNA.
DR   RefSeq; WP_011344285.1; NC_007503.1.
DR   AlphaFoldDB; Q3ACC4; -.
DR   SMR; Q3ACC4; -.
DR   STRING; 246194.CHY_1378; -.
DR   MEROPS; S24.001; -.
DR   EnsemblBacteria; ABB16235; ABB16235; CHY_1378.
DR   KEGG; chy:CHY_1378; -.
DR   eggNOG; COG1974; Bacteria.
DR   HOGENOM; CLU_066192_45_1_9; -.
DR   OMA; HVWLLPH; -.
DR   OrthoDB; 1933795at2; -.
DR   Proteomes; UP000002706; 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..204
FT                   /note="LexA repressor"
FT                   /id="PRO_0000322718"
FT   DNA_BIND        30..50
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            90..91
FT                   /note="Cleavage; by autolysis"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00015"
SQ   SEQUENCE   204 AA;  22824 MW;  4367D646DD96021A CRC64;
     MKNSLLSHQE KKIISFIKQY LNENGYPPTI REICQGVGLS SPSTVHHHLK NLESKGYLQR
     NPTKPRALEL VAEKAPEELL SIPLLGNVAA GYPTLAIENA EEEMQIPKSL FPEKELFALR
     IKGDSMIEEG ILPGDVIIVK KQEVAENGDI VVAYLEGEVT VKKFWKDSVN GVIKLIPANS
     KYEPIIINRE TKILGKVIGL LRRY