ID   LEXA_AERHH              Reviewed;         207 AA.
AC   Q44069; A0KEQ1;
DT   01-NOV-1997, integrated into UniProtKB/Swiss-Prot.
DT   06-MAR-2007, sequence version 2.
DT   03-AUG-2022, entry version 135.
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=AHA_0183;
OS   Aeromonas hydrophila subsp. hydrophila (strain ATCC 7966 / DSM 30187 / BCRC
OS   13018 / CCUG 14551 / JCM 1027 / KCTC 2358 / NCIMB 9240 / NCTC 8049).
OC   Bacteria; Proteobacteria; Gammaproteobacteria; Aeromonadales;
OC   Aeromonadaceae; Aeromonas.
OX   NCBI_TaxID=380703;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RX   PubMed=7867953; DOI=10.1016/0378-1119(94)00836-h;
RA   Riera J., Barbe J.;
RT   "Cloning, sequence and regulation of expression of the lexA gene of
RT   Aeromonas hydrophila.";
RL   Gene 154:71-75(1995).
RN   [2]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=ATCC 7966 / DSM 30187 / BCRC 13018 / CCUG 14551 / JCM 1027 / KCTC
RC   2358 / NCIMB 9240 / NCTC 8049;
RX   PubMed=16980456; DOI=10.1128/jb.00621-06;
RA   Seshadri R., Joseph S.W., Chopra A.K., Sha J., Shaw J., Graf J., Haft D.H.,
RA   Wu M., Ren Q., Rosovitz M.J., Madupu R., Tallon L., Kim M., Jin S.,
RA   Vuong H., Stine O.C., Ali A., Horneman A.J., Heidelberg J.F.;
RT   "Genome sequence of Aeromonas hydrophila ATCC 7966T: jack of all trades.";
RL   J. Bacteriol. 188:8272-8282(2006).
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; X77263; CAA54479.1; -; Genomic_DNA.
DR   EMBL; CP000462; ABK36241.1; -; Genomic_DNA.
DR   PIR; JC4042; JC4042.
DR   RefSeq; WP_011704201.1; NC_008570.1.
DR   RefSeq; YP_854716.1; NC_008570.1.
DR   AlphaFoldDB; Q44069; -.
DR   SMR; Q44069; -.
DR   STRING; 380703.AHA_0183; -.
DR   MEROPS; S24.001; -.
DR   EnsemblBacteria; ABK36241; ABK36241; AHA_0183.
DR   GeneID; 64356628; -.
DR   KEGG; aha:AHA_0183; -.
DR   PATRIC; fig|380703.7.peg.175; -.
DR   eggNOG; COG1974; Bacteria.
DR   HOGENOM; CLU_066192_45_3_6; -.
DR   OMA; HVWLLPH; -.
DR   Proteomes; UP000000756; 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..207
FT                   /note="LexA repressor"
FT                   /id="PRO_0000169997"
FT   DNA_BIND        28..48
FT                   /note="H-T-H motif"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00015"
FT   ACT_SITE        124
FT                   /note="For autocatalytic cleavage activity"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00015"
FT   ACT_SITE        161
FT                   /note="For autocatalytic cleavage activity"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00015"
FT   SITE            89..90
FT                   /note="Cleavage; by autolysis"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00015"
FT   CONFLICT        92
FT                   /note="P -> S (in Ref. 1; CAA54479)"
FT                   /evidence="ECO:0000305"
SQ   SEQUENCE   207 AA;  22908 MW;  A5C4891A9196B960 CRC64;
     MKPLTPRQAE VLELIKANMN ETGMPPTRAE IAQKLGFKSA NAAEEHLKAL AKKGVIEIMP
     GTSRGIRLLL EEEEPLEESG LPLIGKVAAG EPILAQEHIE SHYQVDPALF HPRADFLLRV
     QGMSMKNIGI LDGDLLAVHK TQEVRNGQVV VARLDEDVTV KRFQRKGSQV WLLPENEELS
     PIEVDLSCQQ LTIEGLAVGV IRNADWM