ID   LEXA_IDILO              Reviewed;         205 AA.
AC   Q5QUP5;
DT   15-MAR-2005, integrated into UniProtKB/Swiss-Prot.
DT   04-JAN-2005, sequence version 1.
DT   03-AUG-2022, entry version 110.
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=IL0262;
OS   Idiomarina loihiensis (strain ATCC BAA-735 / DSM 15497 / L2-TR).
OC   Bacteria; Proteobacteria; Gammaproteobacteria; Alteromonadales;
OC   Idiomarinaceae; Idiomarina.
OX   NCBI_TaxID=283942;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=ATCC BAA-735 / DSM 15497 / L2-TR;
RX   PubMed=15596722; DOI=10.1073/pnas.0407638102;
RA   Hou S., Saw J.H., Lee K.S., Freitas T.A., Belisle C., Kawarabayasi Y.,
RA   Donachie S.P., Pikina A., Galperin M.Y., Koonin E.V., Makarova K.S.,
RA   Omelchenko M.V., Sorokin A., Wolf Y.I., Li Q.X., Keum Y.S., Campbell S.,
RA   Denery J., Aizawa S., Shibata S., Malahoff A., Alam M.;
RT   "Genome sequence of the deep-sea gamma-proteobacterium Idiomarina
RT   loihiensis reveals amino acid fermentation as a source of carbon and
RT   energy.";
RL   Proc. Natl. Acad. Sci. U.S.A. 101:18036-18041(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; AE017340; AAV81105.1; -; Genomic_DNA.
DR   RefSeq; WP_011233524.1; NC_006512.1.
DR   AlphaFoldDB; Q5QUP5; -.
DR   SMR; Q5QUP5; -.
DR   STRING; 283942.IL0262; -.
DR   MEROPS; S24.001; -.
DR   EnsemblBacteria; AAV81105; AAV81105; IL0262.
DR   KEGG; ilo:IL0262; -.
DR   eggNOG; COG1974; Bacteria.
DR   HOGENOM; CLU_066192_45_3_6; -.
DR   OMA; HVWLLPH; -.
DR   OrthoDB; 1933795at2; -.
DR   Proteomes; UP000001171; 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..205
FT                   /note="LexA repressor"
FT                   /id="PRO_0000170044"
FT   DNA_BIND        28..48
FT                   /note="H-T-H motif"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00015"
FT   ACT_SITE        122
FT                   /note="For autocatalytic cleavage activity"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00015"
FT   ACT_SITE        159
FT                   /note="For autocatalytic cleavage activity"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00015"
FT   SITE            87..88
FT                   /note="Cleavage; by autolysis"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00015"
SQ   SEQUENCE   205 AA;  22393 MW;  981298740CDBC791 CRC64;
     MRPLTPRQSE ILELIKDNLH ATGMPPTRAE IAHKLGFRSA NSAEEHLKAL ARKGVIEILP
     GMSRGIRLVG DDYDIADGLP LIGQVAAGEP LLAEQHVEGH YKIDESLFHP AASFLLKVNG
     MSMRDIGILD GDLLAVHKTE QARNGQIVVA RVEDEVTVKR FEQRGKTILL HPENEDFSTI
     TVNLAEQVFA IEGLAVGVIR NGATL