ID   LEXA_NITHX              Reviewed;         233 AA.
AC   Q1QMK3;
DT   15-JAN-2008, integrated into UniProtKB/Swiss-Prot.
DT   16-MAY-2006, sequence version 1.
DT   03-AUG-2022, entry version 93.
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=Nham_1729;
OS   Nitrobacter hamburgensis (strain DSM 10229 / NCIMB 13809 / X14).
OC   Bacteria; Proteobacteria; Alphaproteobacteria; Hyphomicrobiales;
OC   Bradyrhizobiaceae; Nitrobacter.
OX   NCBI_TaxID=323097;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=DSM 10229 / NCIMB 13809 / X14;
RG   US DOE Joint Genome Institute;
RA   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   Chain P., Malfatti S., Shin M., Vergez L., Schmutz J., Larimer F., Land M.,
RA   Hauser L., Kyrpides N., Ivanova N., Ward B., Arp D., Klotz M., Stein L.,
RA   O'Mullan G., Starkenburg S., Sayavedra L., Poret-Peterson A.T.,
RA   Gentry M.E., Bruce D., Richardson P.;
RT   "Complete sequence of chromosome of Nitrobacter hamburgensis X14.";
RL   Submitted (MAR-2006) to the EMBL/GenBank/DDBJ databases.
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; CP000319; ABE62544.1; -; Genomic_DNA.
DR   RefSeq; WP_011510226.1; NC_007964.1.
DR   AlphaFoldDB; Q1QMK3; -.
DR   SMR; Q1QMK3; -.
DR   STRING; 323097.Nham_1729; -.
DR   MEROPS; S24.001; -.
DR   EnsemblBacteria; ABE62544; ABE62544; Nham_1729.
DR   KEGG; nha:Nham_1729; -.
DR   eggNOG; COG1974; Bacteria.
DR   HOGENOM; CLU_066192_45_2_5; -.
DR   OMA; HVWLLPH; -.
DR   OrthoDB; 1933795at2; -.
DR   Proteomes; UP000001953; 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..233
FT                   /note="LexA repressor"
FT                   /id="PRO_1000001308"
FT   DNA_BIND        26..46
FT                   /note="H-T-H motif"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00015"
FT   ACT_SITE        154
FT                   /note="For autocatalytic cleavage activity"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00015"
FT   ACT_SITE        192
FT                   /note="For autocatalytic cleavage activity"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00015"
FT   SITE            119..120
FT                   /note="Cleavage; by autolysis"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00015"
SQ   SEQUENCE   233 AA;  25560 MW;  0C4600113F22D5D0 CRC64;
     MLTRKQYELL RFINERLKES GVPPSFDEMK DALDLRSKSG IHRLITALEE RGFIRRLPNR
     ARAIEVIKLP EVAGNGGGRR GFTPSVIEGN LGKVRPSGGG VVDDAERPVA VPVMGRIAAG
     TPIEALQTRS HTISVPPDML GSGEHYALEV RGDSMVEAGI LDGDMALIQR NETAETGDIV
     VALIDDEEAT LKRFRRRGAS IALEPANTAY EVRILPPNRV QIQGKLIGIY RKY