ID   LEXA_MYCTA              Reviewed;         236 AA.
AC   A5U672;
DT   15-JAN-2008, integrated into UniProtKB/Swiss-Prot.
DT   05-APR-2011, sequence version 2.
DT   03-AUG-2022, entry version 89.
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=MRA_2748;
OS   Mycobacterium tuberculosis (strain ATCC 25177 / H37Ra).
OC   Bacteria; Actinobacteria; Corynebacteriales; Mycobacteriaceae;
OC   Mycobacterium; Mycobacterium tuberculosis complex.
OX   NCBI_TaxID=419947;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=ATCC 25177 / H37Ra;
RX   PubMed=18584054; DOI=10.1371/journal.pone.0002375;
RA   Zheng H., Lu L., Wang B., Pu S., Zhang X., Zhu G., Shi W., Zhang L.,
RA   Wang H., Wang S., Zhao G., Zhang Y.;
RT   "Genetic basis of virulence attenuation revealed by comparative genomic
RT   analysis of Mycobacterium tuberculosis strain H37Ra versus H37Rv.";
RL   PLoS ONE 3:E2375-E2375(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}.
CC   -!- SEQUENCE CAUTION:
CC       Sequence=ABQ74522.1; Type=Erroneous initiation; Note=Truncated N-terminus.; Evidence={ECO:0000305};
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DR   EMBL; CP000611; ABQ74522.1; ALT_INIT; Genomic_DNA.
DR   RefSeq; WP_003899448.1; NZ_CP016972.1.
DR   AlphaFoldDB; A5U672; -.
DR   SMR; A5U672; -.
DR   STRING; 419947.MRA_2748; -.
DR   MEROPS; S24.001; -.
DR   EnsemblBacteria; ABQ74522; ABQ74522; MRA_2748.
DR   GeneID; 45426707; -.
DR   KEGG; mra:MRA_2748; -.
DR   eggNOG; COG1974; Bacteria.
DR   HOGENOM; CLU_066192_45_0_11; -.
DR   OrthoDB; 1933795at2; -.
DR   Proteomes; UP000001988; 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; Repressor; SOS response; Transcription;
KW   Transcription regulation.
FT   CHAIN           1..236
FT                   /note="LexA repressor"
FT                   /id="PRO_1000001305"
FT   DNA_BIND        51..71
FT                   /note="H-T-H motif"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00015"
FT   REGION          1..25
FT                   /note="Disordered"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   ACT_SITE        160
FT                   /note="For autocatalytic cleavage activity"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00015"
FT   ACT_SITE        197
FT                   /note="For autocatalytic cleavage activity"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00015"
FT   SITE            125..126
FT                   /note="Cleavage; by autolysis"
FT                   /evidence="ECO:0000255|HAMAP-Rule:MF_00015"
SQ   SEQUENCE   236 AA;  24841 MW;  BF88E0D234B3A051 CRC64;
     MNDSNDTSVA GGAAGADSRV LSADSALTER QRTILDVIRA SVTSRGYPPS IREIGDAVGL
     TSTSSVAHQL RTLERKGYLR RDPNRPRAVN VRGADDAALP PVTEVAGSDA LPEPTFVPVL
     GRIAAGGPIL AEEAVEDVFP LPRELVGEGT LFLLKVIGDS MVEAAICDGD WVVVRQQNVA
     DNGDIVAAMI DGEATVKTFK RAGGQVWLMP HNPAFDPIPG NDATVLGKVV TVIRKV