ID   LEXA_BACCQ              Reviewed;         206 AA.
AC   B9IUL2;
DT   28-JUL-2009, integrated into UniProtKB/Swiss-Prot.
DT   24-MAR-2009, sequence version 1.
DT   03-AUG-2022, entry version 80.
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=BCQ_3494;
OS   Bacillus cereus (strain Q1).
OC   Bacteria; Firmicutes; Bacilli; Bacillales; Bacillaceae; Bacillus;
OC   Bacillus cereus group.
OX   NCBI_TaxID=361100;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=Q1;
RX   PubMed=19060151; DOI=10.1128/jb.01629-08;
RA   Xiong Z., Jiang Y., Qi D., Lu H., Yang F., Yang J., Chen L., Sun L., Xu X.,
RA   Xue Y., Zhu Y., Jin Q.;
RT   "Complete genome sequence of the extremophilic Bacillus cereus strain Q1
RT   with industrial applications.";
RL   J. Bacteriol. 191:1120-1121(2009).
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; CP000227; ACM13922.1; -; Genomic_DNA.
DR   RefSeq; WP_000413738.1; NC_011969.1.
DR   AlphaFoldDB; B9IUL2; -.
DR   SMR; B9IUL2; -.
DR   MEROPS; S24.001; -.
DR   EnsemblBacteria; ACM13922; ACM13922; BCQ_3494.
DR   GeneID; 59155806; -.
DR   GeneID; 64202240; -.
DR   GeneID; 67508337; -.
DR   KEGG; bcq:BCQ_3494; -.
DR   HOGENOM; CLU_066192_45_1_9; -.
DR   OMA; HVWLLPH; -.
DR   Proteomes; UP000000441; 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..206
FT                   /note="LexA repressor"
FT                   /id="PRO_1000116595"
FT   DNA_BIND        28..48
FT                   /note="H-T-H motif"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00015"
FT   ACT_SITE        128
FT                   /note="For autocatalytic cleavage activity"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00015"
FT   ACT_SITE        166
FT                   /note="For autocatalytic cleavage activity"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00015"
FT   SITE            92..93
FT                   /note="Cleavage; by autolysis"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00015"
SQ   SEQUENCE   206 AA;  22890 MW;  CC4077E937DF8D09 CRC64;
     MEKLTKRQQD ILDFIKLKVQ EKGYPPSVRE IGQAVGLASS STVHGHLSRL EEKGYIRRDP
     TKPRAIEILG EDRMDTETQS VIQVPIVGKV TAGLPITAVE SVEEHFPLPA SIVAGADQVF
     MLRISGDSMI EAGIFDGDLV VVRQQQSAYN GEIVVALTED NEATVKRFYK EKDHFRLQPE
     NSSLEPIILK QVSVIGKVIG VYRDLH