ID   LEXA_SALPK              Reviewed;         202 AA.
AC   B5BJW0;
DT   24-MAR-2009, integrated into UniProtKB/Swiss-Prot.
DT   23-SEP-2008, sequence version 1.
DT   03-AUG-2022, entry version 78.
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=SSPA3763;
OS   Salmonella paratyphi A (strain AKU_12601).
OC   Bacteria; Proteobacteria; Gammaproteobacteria; Enterobacterales;
OC   Enterobacteriaceae; Salmonella.
OX   NCBI_TaxID=554290;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=AKU_12601;
RX   PubMed=19159446; DOI=10.1186/1471-2164-10-36;
RA   Holt K.E., Thomson N.R., Wain J., Langridge G.C., Hasan R., Bhutta Z.A.,
RA   Quail M.A., Norbertczak H., Walker D., Simmonds M., White B., Bason N.,
RA   Mungall K., Dougan G., Parkhill J.;
RT   "Pseudogene accumulation in the evolutionary histories of Salmonella
RT   enterica serovars Paratyphi A and Typhi.";
RL   BMC Genomics 10:36-36(2009).
CC   -!- FUNCTION: Represses a number of genes involved in the response to DNA
CC       damage (SOS response), including recA and lexA. Binds to the 16 bp
CC       palindromic sequence 5'-CTGTATATATATACAG-3'. In the presence of single-
CC       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; FM200053; CAR62047.1; -; Genomic_DNA.
DR   RefSeq; WP_000646079.1; NC_011147.1.
DR   AlphaFoldDB; B5BJW0; -.
DR   SMR; B5BJW0; -.
DR   MEROPS; S24.001; -.
DR   KEGG; sek:SSPA3763; -.
DR   HOGENOM; CLU_066192_45_3_6; -.
DR   OMA; HVWLLPH; -.
DR   Proteomes; UP000001869; 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; Repressor; SOS response; Transcription;
KW   Transcription regulation.
FT   CHAIN           1..202
FT                   /note="LexA repressor"
FT                   /id="PRO_1000089596"
FT   DNA_BIND        28..48
FT                   /note="H-T-H motif"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00015"
FT   ACT_SITE        119
FT                   /note="For autocatalytic cleavage activity"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00015"
FT   ACT_SITE        156
FT                   /note="For autocatalytic cleavage activity"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00015"
FT   SITE            84..85
FT                   /note="Cleavage; by autolysis"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00015"
SQ   SEQUENCE   202 AA;  22305 MW;  6BC34EA11A70430C CRC64;
     MKALTARQQE VFDLIRDHIS QTGMPPTRAE IAQRLGFRSP NAAEEHLKAL ARKGVLEIVS
     GASRGIRLLQ EEEDGLPLVG RVAAGEPLLA QQHIEGHYQV DPSLFKPSAD FLLRVSGMSM
     KDIGIMDGDL LAVHKTQDVR NGQVVVARID DEVTVKRLKK QGNKVELLPE NSEFTPIVVD
     LREQSFTIEG LAVGVIRNGE WL