ID   LEXA_SACD2              Reviewed;         201 AA.
AC   Q21JT2;
DT   15-JAN-2008, integrated into UniProtKB/Swiss-Prot.
DT   18-APR-2006, sequence version 1.
DT   03-AUG-2022, entry version 99.
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=Sde_1787;
OS   Saccharophagus degradans (strain 2-40 / ATCC 43961 / DSM 17024).
OC   Bacteria; Proteobacteria; Gammaproteobacteria; Cellvibrionales;
OC   Cellvibrionaceae; Saccharophagus.
OX   NCBI_TaxID=203122;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=2-40 / ATCC 43961 / DSM 17024;
RX   PubMed=18516288; DOI=10.1371/journal.pgen.1000087;
RA   Weiner R.M., Taylor L.E. II, Henrissat B., Hauser L., Land M.,
RA   Coutinho P.M., Rancurel C., Saunders E.H., Longmire A.G., Zhang H.,
RA   Bayer E.A., Gilbert H.J., Larimer F., Zhulin I.B., Ekborg N.A., Lamed R.,
RA   Richardson P.M., Borovok I., Hutcheson S.;
RT   "Complete genome sequence of the complex carbohydrate-degrading marine
RT   bacterium, Saccharophagus degradans strain 2-40 T.";
RL   PLoS Genet. 4:E1000087-E1000087(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; CP000282; ABD81047.1; -; Genomic_DNA.
DR   RefSeq; WP_011468267.1; NC_007912.1.
DR   AlphaFoldDB; Q21JT2; -.
DR   SMR; Q21JT2; -.
DR   STRING; 203122.Sde_1787; -.
DR   MEROPS; S24.001; -.
DR   EnsemblBacteria; ABD81047; ABD81047; Sde_1787.
DR   KEGG; sde:Sde_1787; -.
DR   eggNOG; COG1974; Bacteria.
DR   HOGENOM; CLU_066192_45_3_6; -.
DR   OMA; HVWLLPH; -.
DR   OrthoDB; 1933795at2; -.
DR   Proteomes; UP000001947; 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..201
FT                   /note="LexA repressor"
FT                   /id="PRO_1000001331"
FT   DNA_BIND        28..48
FT                   /note="H-T-H motif"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00015"
FT   ACT_SITE        118
FT                   /note="For autocatalytic cleavage activity"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00015"
FT   ACT_SITE        155
FT                   /note="For autocatalytic cleavage activity"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00015"
FT   SITE            83..84
FT                   /note="Cleavage; by autolysis"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00015"
SQ   SEQUENCE   201 AA;  22350 MW;  9647161BF50E11C9 CRC64;
     MYKLTTRQQE VLDLIKSHIE DTGYPPTRAE IANQLGFRSA NAAEEHLKAL ARKGAIEMVP
     GASRGIRLPE TIQGIPLIGR VAAGNPILAE QNIEDYCDVP PDFFYPQANY LLKVQGMSMR
     DAGILDGDLL AVHSTTQVKN GDIVVARIED EVTVKRFKRE RNNATIQLLP ENPDFNIIEV
     DLRDANFSIE GLSVGIIRRE L