ID   LEXA_LACCB              Reviewed;         208 AA.
AC   B3WC17;
DT   24-MAR-2009, integrated into UniProtKB/Swiss-Prot.
DT   02-SEP-2008, sequence version 1.
DT   03-AUG-2022, entry version 85.
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=LCABL_07950;
OS   Lacticaseibacillus casei (strain BL23) (Lactobacillus casei).
OC   Bacteria; Firmicutes; Bacilli; Lactobacillales; Lactobacillaceae;
OC   Lacticaseibacillus.
OX   NCBI_TaxID=543734;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=BL23;
RA   Maze A., Boel G., Bourand A., Loux V., Gibrat J.F., Zuniga M., Hartke A.,
RA   Deutscher J.;
RT   "Lactobacillus casei BL23 complete genome sequence.";
RL   Submitted (JUN-2008) 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; FM177140; CAQ65918.1; -; Genomic_DNA.
DR   RefSeq; WP_003563873.1; NC_010999.1.
DR   AlphaFoldDB; B3WC17; -.
DR   SMR; B3WC17; -.
DR   MEROPS; S24.001; -.
DR   KEGG; lcb:LCABL_07950; -.
DR   HOGENOM; CLU_066192_45_1_9; -.
DR   OMA; HVWLLPH; -.
DR   OrthoDB; 1933795at2; -.
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..208
FT                   /note="LexA repressor"
FT                   /id="PRO_1000089571"
FT   DNA_BIND        30..50
FT                   /note="H-T-H motif"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00015"
FT   ACT_SITE        129
FT                   /note="For autocatalytic cleavage activity"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00015"
FT   ACT_SITE        167
FT                   /note="For autocatalytic cleavage activity"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00015"
FT   SITE            93..94
FT                   /note="Cleavage; by autolysis"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00015"
SQ   SEQUENCE   208 AA;  22786 MW;  047EE73A36CA9AC0 CRC64;
     MPTQASQKRW KQILQSIYDA IEDHGYPPTV REIGKSVGLS SSSTVAAYLE KLLAAGLIAK
     DPAKPRTLEV TSAGRDFIGV QDHGIPIVGT VAAGVPITAI ENIDDYFPVP DDLPYAADEL
     FMLRVQGNSM IKIGILDGDQ IIVKKQNDAE NGQIVVAMTE EDEATVKRFY KEKNGIRLHP
     ENDSMDDMFF PDVTILGIVV SLYRPALV