ID   LEXA_PSELT              Reviewed;         200 AA.
AC   A8F429;
DT   18-MAR-2008, integrated into UniProtKB/Swiss-Prot.
DT   13-NOV-2007, sequence version 1.
DT   03-AUG-2022, entry version 83.
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=Tlet_0345;
OS   Pseudothermotoga lettingae (strain ATCC BAA-301 / DSM 14385 / NBRC 107922 /
OS   TMO) (Thermotoga lettingae).
OC   Bacteria; Thermotogae; Thermotogales; Thermotogaceae; Pseudothermotoga.
OX   NCBI_TaxID=416591;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=ATCC BAA-301 / DSM 14385 / NBRC 107922 / TMO;
RG   US DOE Joint Genome Institute;
RA   Copeland A., Lucas S., Lapidus A., Barry K., Glavina del Rio T., Dalin E.,
RA   Tice H., Pitluck S., Foster B., Bruce D., Schmutz J., Larimer F., Land M.,
RA   Hauser L., Kyrpides N., Mikhailova N., Nelson K., Gogarten J.P., Noll K.,
RA   Richardson P.;
RT   "Complete sequence of Thermotoga lettingae TMO.";
RL   Submitted (AUG-2007) 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; CP000812; ABV32913.1; -; Genomic_DNA.
DR   RefSeq; WP_012002394.1; NC_009828.1.
DR   AlphaFoldDB; A8F429; -.
DR   SMR; A8F429; -.
DR   STRING; 416591.Tlet_0345; -.
DR   MEROPS; S24.001; -.
DR   EnsemblBacteria; ABV32913; ABV32913; Tlet_0345.
DR   KEGG; tle:Tlet_0345; -.
DR   eggNOG; COG1974; Bacteria.
DR   HOGENOM; CLU_066192_45_1_0; -.
DR   OMA; HVWLLPH; -.
DR   OrthoDB; 1933795at2; -.
DR   Proteomes; UP000002016; 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..200
FT                   /note="LexA repressor"
FT                   /id="PRO_0000322770"
FT   DNA_BIND        29..48
FT                   /note="H-T-H motif"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00015"
FT   ACT_SITE        120
FT                   /note="For autocatalytic cleavage activity"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00015"
FT   ACT_SITE        158
FT                   /note="For autocatalytic cleavage activity"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00015"
FT   SITE            84..85
FT                   /note="Cleavage; by autolysis"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00015"
SQ   SEQUENCE   200 AA;  22519 MW;  49F0EB0401E69F98 CRC64;
     MKKELTDRQK KILDFVLSYI DSHGYPPSIR DIARAFRITP RGAIVHLNAL EKKGYLTRGK
     RARSIKVLNR SEAIRLPVVG TIAAGNAIEA IENPTEIIEV PKAMIKIGFD HFLLRVRGES
     MIEEHILDKD YVVIRKQNTA NNGDIVAVLT NSNEATLKKI YIEPEKIILK PANSKMQPIE
     LKPENVKILG KMVGVIRIYG