ID   LEXA_METCA              Reviewed;         202 AA.
AC   Q605V8;
DT   01-FEB-2005, integrated into UniProtKB/Swiss-Prot.
DT   23-NOV-2004, sequence version 1.
DT   03-AUG-2022, entry version 101.
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=MCA2167;
OS   Methylococcus capsulatus (strain ATCC 33009 / NCIMB 11132 / Bath).
OC   Bacteria; Proteobacteria; Gammaproteobacteria; Methylococcales;
OC   Methylococcaceae; Methylococcus.
OX   NCBI_TaxID=243233;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=ATCC 33009 / NCIMB 11132 / Bath;
RX   PubMed=15383840; DOI=10.1371/journal.pbio.0020303;
RA   Ward N.L., Larsen O., Sakwa J., Bruseth L., Khouri H.M., Durkin A.S.,
RA   Dimitrov G., Jiang L., Scanlan D., Kang K.H., Lewis M.R., Nelson K.E.,
RA   Methe B.A., Wu M., Heidelberg J.F., Paulsen I.T., Fouts D.E., Ravel J.,
RA   Tettelin H., Ren Q., Read T.D., DeBoy R.T., Seshadri R., Salzberg S.L.,
RA   Jensen H.B., Birkeland N.K., Nelson W.C., Dodson R.J., Grindhaug S.H.,
RA   Holt I.E., Eidhammer I., Jonasen I., Vanaken S., Utterback T.R.,
RA   Feldblyum T.V., Fraser C.M., Lillehaug J.R., Eisen J.A.;
RT   "Genomic insights into methanotrophy: the complete genome sequence of
RT   Methylococcus capsulatus (Bath).";
RL   PLoS Biol. 2:1616-1628(2004).
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; AE017282; AAU91609.1; -; Genomic_DNA.
DR   RefSeq; WP_010961403.1; NC_002977.6.
DR   AlphaFoldDB; Q605V8; -.
DR   SMR; Q605V8; -.
DR   STRING; 243233.MCA2167; -.
DR   MEROPS; S24.001; -.
DR   EnsemblBacteria; AAU91609; AAU91609; MCA2167.
DR   KEGG; mca:MCA2167; -.
DR   eggNOG; COG1974; Bacteria.
DR   HOGENOM; CLU_066192_45_3_6; -.
DR   OMA; HVWLLPH; -.
DR   OrthoDB; 1933795at2; -.
DR   Proteomes; UP000006821; 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_0000170055"
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            85..86
FT                   /note="Cleavage; by autolysis"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00015"
SQ   SEQUENCE   202 AA;  22233 MW;  B7D5EABF7ACC732B CRC64;
     MKPLTVRQRE ILDCIRRSVE NEGFPPTIAE IARAIGVSSP HGVREQLRAL ERKGVIELIP
     SASRGIRLLA RAEEPGLPLI GKVAAGRPLL TEAQVERYCQ LGPELFEHKG DYLLRVQGMS
     MRDAGIIDGD LLVVQQAQEA RSGQIVVVRL HDEVTVKRLR LEGALAYLEP ANPEFSVIAV
     DPERQPLCIE GIVVGVIRTR VG