ID   LEXA_SYNC1              Reviewed;         202 AA.
AC   Q3A3S5;
DT   15-JAN-2008, integrated into UniProtKB/Swiss-Prot.
DT   22-NOV-2005, sequence version 1.
DT   03-AUG-2022, entry version 105.
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=Pcar_1739;
OS   Syntrophotalea carbinolica (strain DSM 2380 / NBRC 103641 / GraBd1)
OS   (Pelobacter carbinolicus).
OC   Bacteria; Proteobacteria; Deltaproteobacteria; Desulfuromonadales;
OC   Syntrophotaleaceae; Syntrophotalea.
OX   NCBI_TaxID=338963;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=DSM 2380 / NBRC 103641 / GraBd1;
RA   Copeland A., Lucas S., Lapidus A., Barry K., Detter J.C., Glavina T.,
RA   Hammon N., Israni S., Pitluck S., Chertkov O., Schmutz J., Larimer F.,
RA   Land M., Kyrpides N., Ivanova N., Richardson P.;
RT   "Complete sequence of Pelobacter carbinolicus DSM 2380.";
RL   Submitted (OCT-2005) to the EMBL/GenBank/DDBJ databases.
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; CP000142; ABA88982.1; -; Genomic_DNA.
DR   RefSeq; WP_011341474.1; NC_007498.2.
DR   AlphaFoldDB; Q3A3S5; -.
DR   SMR; Q3A3S5; -.
DR   STRING; 338963.Pcar_1739; -.
DR   MEROPS; S24.001; -.
DR   PRIDE; Q3A3S5; -.
DR   EnsemblBacteria; ABA88982; ABA88982; Pcar_1739.
DR   KEGG; pca:Pcar_1739; -.
DR   eggNOG; COG1974; Bacteria.
DR   HOGENOM; CLU_066192_45_1_7; -.
DR   OMA; DDEFHIR; -.
DR   OrthoDB; 1933795at2; -.
DR   Proteomes; UP000002534; 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; cd06529; S24_LexA-like; 1.
DR   Gene3D; 1.10.10.10; -; 1.
DR   HAMAP; MF_00015; LexA; 1.
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..202
FT                   /note="LexA repressor"
FT                   /id="PRO_1000001314"
FT   DNA_BIND        28..48
FT                   /note="H-T-H motif"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00015"
FT   ACT_SITE        120
FT                   /note="For autocatalytic cleavage activity"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00015"
FT   ACT_SITE        157
FT                   /note="For autocatalytic cleavage activity"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00015"
FT   SITE            86..87
FT                   /note="Cleavage; by autolysis"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00015"
SQ   SEQUENCE   202 AA;  22393 MW;  5CC1990A7DB10F11 CRC64;
     MSPLTPKQKQ VFDYIARHIG EQGFAPSQQE IARAFGFRSL GTVRNYLVRL EREGLLERNW
     NARRGLQLRT ASERGMKLPL AGTVAAGKPI EAIEIPDVIE VPPTMVGSGE HFVLRVAGDS
     MIGDGIIDGD YVVVRKQATA EHGQTVVALL DNEATVKRLH RRNDRIELHP ANPSMQPIVV
     TDPDNFRIEG VVVGVIRHYR SA