ID   LEXA_AERS4              Reviewed;         207 AA.
AC   A4STB3;
DT   15-JAN-2008, integrated into UniProtKB/Swiss-Prot.
DT   15-MAY-2007, sequence version 1.
DT   04-NOV-2026, entry version 105.
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};
GN   OrderedLocusNames=ASA_4206;
OS   Aeromonas salmonicida (strain A449).
OC   Bacteria; Pseudomonadati; Pseudomonadota; Gammaproteobacteria;
OC   Aeromonadales; Aeromonadaceae; Aeromonas.
OX   NCBI_TaxID=382245;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=A449;
RX   PubMed=18801193; DOI=10.1186/1471-2164-9-427;
RA   Reith M.E., Singh R.K., Curtis B., Boyd J.M., Bouevitch A., Kimball J.,
RA   Munholland J., Murphy C., Sarty D., Williams J., Nash J.H., Johnson S.C.,
RA   Brown L.L.;
RT   "The genome of Aeromonas salmonicida subsp. salmonicida A449: insights into
RT   the evolution of a fish pathogen.";
RL   BMC Genomics 9:427-427(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; CP000644; ABO92135.1; -; Genomic_DNA.
DR   RefSeq; WP_005321237.1; NC_009348.1.
DR   AlphaFoldDB; A4STB3; -.
DR   SMR; A4STB3; -.
DR   STRING; 29491.GCA_000820065_04464; -.
DR   MEROPS; S24.001; -.
DR   GeneID; 79877642; -.
DR   KEGG; asa:ASA_4206; -.
DR   eggNOG; COG1974; Bacteria.
DR   HOGENOM; CLU_066192_45_3_6; -.
DR   OMA; AAHDHLC; -.
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 DNA-templated transcription; 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   FunFam; 1.10.10.10:FF:000009; LexA repressor; 1.
DR   FunFam; 2.10.109.10:FF:000001; LexA repressor; 1.
DR   Gene3D; 2.10.109.10; Umud Fragment, subunit A; 1.
DR   Gene3D; 1.10.10.10; Winged helix-like DNA-binding domain superfamily/Winged helix DNA-binding domain; 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; IPR050077; LexA_repressor.
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   NCBIfam; TIGR00498; lexA; 1.
DR   PANTHER; PTHR33516; LEXA REPRESSOR; 1.
DR   PANTHER; PTHR33516:SF2; LEXA REPRESSOR-RELATED; 1.
DR   Pfam; PF01726; LexA_DNA_bind; 1.
DR   Pfam; PF00717; Peptidase_S24; 1.
DR   PRINTS; PR00726; LEXASERPTASE.
DR   SUPFAM; SSF51306; LexA/Signal peptidase; 1.
DR   SUPFAM; SSF46785; Winged helix' DNA-binding domain; 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..207
FT                   /note="LexA repressor"
FT                   /id="PRO_1000001253"
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"
SQ   SEQUENCE   207 AA;  22852 MW;  E484BE4A4ACE9529 CRC64;
     MKPLTPRQAE VLELIKVNMS ETGMPPTRAE IAQKLGFKSA NAAEEHLKAL AKKGVIEIMP
     GTSRGIRLLI EEEAVLEETG LPLIGKVAAG EPILAQEHIE SHYQVDPALF HPRADFLLRV
     QGMSMKNIGI LDGDLLAVHK TQEVRNGQVV VARLDEDVTV KRFQRKGSQV WLLPENEELE
     PIAVDLSCQQ LTIEGLAVGV IRNADWM
//