ID   LEXA_BIFLD              Reviewed;         241 AA.
AC   B3DQB4;
DT   24-MAR-2009, integrated into UniProtKB/Swiss-Prot.
DT   22-JUL-2008, sequence version 1.
DT   03-AUG-2022, entry version 79.
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=BLD_0167;
OS   Bifidobacterium longum (strain DJO10A).
OC   Bacteria; Actinobacteria; Bifidobacteriales; Bifidobacteriaceae;
OC   Bifidobacterium.
OX   NCBI_TaxID=205913;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=DJO10A;
RX   PubMed=18505588; DOI=10.1186/1471-2164-9-247;
RA   Lee J.H., Karamychev V.N., Kozyavkin S.A., Mills D., Pavlov A.R.,
RA   Pavlova N.V., Polouchine N.N., Richardson P.M., Shakhova V.V.,
RA   Slesarev A.I., Weimer B., O'Sullivan D.J.;
RT   "Comparative genomic analysis of the gut bacterium Bifidobacterium longum
RT   reveals loci susceptible to deletion during pure culture growth.";
RL   BMC Genomics 9:247-247(2008).
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; CP000605; ACD97613.1; -; Genomic_DNA.
DR   RefSeq; WP_007052535.1; NZ_AABM02000003.1.
DR   AlphaFoldDB; B3DQB4; -.
DR   SMR; B3DQB4; -.
DR   MEROPS; S24.001; -.
DR   EnsemblBacteria; ACD97613; ACD97613; BLD_0167.
DR   GeneID; 66505528; -.
DR   KEGG; blj:BLD_0167; -.
DR   HOGENOM; CLU_066192_45_0_11; -.
DR   OMA; HVWLLPH; -.
DR   Proteomes; UP000002419; 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..241
FT                   /note="LexA repressor"
FT                   /id="PRO_1000089547"
FT   DNA_BIND        41..61
FT                   /note="H-T-H motif"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00015"
FT   ACT_SITE        165
FT                   /note="For autocatalytic cleavage activity"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00015"
FT   ACT_SITE        202
FT                   /note="For autocatalytic cleavage activity"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00015"
FT   SITE            130..131
FT                   /note="Cleavage; by autolysis"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00015"
SQ   SEQUENCE   241 AA;  26049 MW;  E8A4C6300737A9D3 CRC64;
     MSTIPFSPKQ KPDESTLTDR QRKVLDAIRT HIDEQGFAPS FREIGNAAGL KSPSSVKHQL
     QVLEDKGFIR MNANKGRAIE VVAGSAPNAE KPSQASEEAT STSNVAEIYQ FPAEAIAESH
     DVPLVGRIAA GVPITAEQHV DDVMRLPERL TGSGTLFMLE VHGDSMVDAA ICDGDYVVVR
     EQNSAVNGDI VAALLDDEAT VKTFRKENGH VWLMPHNPAY SPIDGTHATI MGKVVTVLRK
     L