ID   LEXA_ALKMQ              Reviewed;         206 AA.
AC   A6TR70;
DT   05-FEB-2008, integrated into UniProtKB/Swiss-Prot.
DT   21-AUG-2007, 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=Amet_2535;
OS   Alkaliphilus metalliredigens (strain QYMF).
OC   Bacteria; Firmicutes; Clostridia; Eubacteriales; Clostridiaceae;
OC   Alkaliphilus.
OX   NCBI_TaxID=293826;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=QYMF;
RX   PubMed=27811105; DOI=10.1128/genomea.01226-16;
RA   Hwang C., Copeland A., Lucas S., Lapidus A., Barry K., Detter J.C.,
RA   Glavina Del Rio T., Hammon N., Israni S., Dalin E., Tice H., Pitluck S.,
RA   Chertkov O., Brettin T., Bruce D., Han C., Schmutz J., Larimer F.,
RA   Land M.L., Hauser L., Kyrpides N., Mikhailova N., Ye Q., Zhou J.,
RA   Richardson P., Fields M.W.;
RT   "Complete genome sequence of Alkaliphilus metalliredigens strain QYMF, an
RT   alkaliphilic and metal-reducing bacterium isolated from borax-contaminated
RT   leachate ponds.";
RL   Genome Announc. 4:0-0(2016).
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; CP000724; ABR48688.1; -; Genomic_DNA.
DR   RefSeq; WP_012063663.1; NC_009633.1.
DR   AlphaFoldDB; A6TR70; -.
DR   SMR; A6TR70; -.
DR   STRING; 293826.Amet_2535; -.
DR   MEROPS; S24.001; -.
DR   EnsemblBacteria; ABR48688; ABR48688; Amet_2535.
DR   KEGG; amt:Amet_2535; -.
DR   eggNOG; COG1974; Bacteria.
DR   HOGENOM; CLU_066192_45_1_9; -.
DR   OMA; HVWLLPH; -.
DR   OrthoDB; 1933795at2; -.
DR   Proteomes; UP000001572; 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..206
FT                   /note="LexA repressor"
FT                   /id="PRO_1000057124"
FT   DNA_BIND        29..49
FT                   /note="H-T-H motif"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00015"
FT   ACT_SITE        130
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            95..96
FT                   /note="Cleavage; by autolysis"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00015"
SQ   SEQUENCE   206 AA;  23048 MW;  0AE5928731CD96BB CRC64;
     MYEDLNDNQI KILHYMKSEI SQKGYPPSVR EICQAVGLKS TSTAHGHLSK LELKGYIRRD
     ATKPRAIEIL SQGDEQSPYI HKEIINVPIV GKVTAGQPIL AVENIEDTFP LPIDFVDSES
     TFILTVKGDS MIDDGIHEND YVVVRQQSDA RNGDIVVALI DDSATVKRFY REKDHIRLQP
     SNTSMSPILV DDVTILGKVT GVFRKI