ID   SIGK_MYCTA              Reviewed;         187 AA.
AC   A5TZH1;
DT   15-JAN-2008, integrated into UniProtKB/Swiss-Prot.
DT   10-JUL-2007, sequence version 1.
DT   25-MAY-2022, entry version 85.
DE   RecName: Full=ECF RNA polymerase sigma factor SigK;
DE            Short=ECF sigma factor SigK;
DE   AltName: Full=Alternative RNA polymerase sigma factor SigK;
DE   AltName: Full=RNA polymerase sigma-K factor;
DE            Short=Sigma-K factor;
GN   Name=sigK; OrderedLocusNames=MRA_0450;
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: Sigma factors are initiation factors that promote the
CC       attachment of RNA polymerase to specific initiation sites and are then
CC       released. Extracytoplasmic function (ECF) sigma factors are held in an
CC       inactive form by an anti-sigma factor until released by regulated
CC       intramembrane proteolysis (By similarity). {ECO:0000250}.
CC   -!- SUBUNIT: Interacts transiently with the RNA polymerase catalytic core
CC       formed by RpoA, RpoB, RpoC and RpoZ (2 alpha, 1 beta, 1 beta' and 1
CC       omega subunit) to form the RNA polymerase holoenzyme that can initiate
CC       transcription. Interacts (via sigma-70 factor domain 4) with anti-
CC       sigma-K factor RskA (By similarity). {ECO:0000250}.
CC   -!- DOMAIN: The sigma-70 factor domain-2 mediates sequence-specific
CC       interaction with the -10 element in promoter DNA, and plays an
CC       important role in melting the double-stranded DNA and the formation of
CC       the transcription bubble. The sigma-70 factor domain-2 mediates
CC       interaction with the RNA polymerase subunits RpoB and RpoC (By
CC       similarity). {ECO:0000250}.
CC   -!- DOMAIN: The sigma-70 factor domain-4 contains a helix-turn-helix (H-T-
CC       H) motif that mediates interaction with the -35 element in promoter
CC       DNA. The domain also mediates interaction with the RNA polymerase
CC       subunit RpoA. Interactions between sigma-70 factor domain-4 and anti-
CC       sigma factors prevents interaction of sigma factors with the RNA
CC       polymerase catalytic core (By similarity). {ECO:0000250}.
CC   -!- MISCELLANEOUS: Extracytoplasmic function (ECF) sigma factors are held
CC       in an inactive form by an anti-sigma factor until released by regulated
CC       intramembrane proteolysis (RIP). RIP occurs when an extracytoplasmic
CC       signal triggers a concerted proteolytic cascade to transmit information
CC       and elicit cellular responses. The membrane-spanning anti-sigma factor
CC       is first cut extracytoplasmically (site-1 protease, S1P), then within
CC       the membrane itself (site-2 protease, S2P, Rip1), while cytoplasmic
CC       proteases finish degrading the regulatory protein, liberating SigK (By
CC       similarity). {ECO:0000250}.
CC   -!- SIMILARITY: Belongs to the sigma-70 factor family. ECF subfamily.
CC       {ECO:0000305}.
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DR   EMBL; CP000611; ABQ72171.1; -; Genomic_DNA.
DR   RefSeq; WP_003402246.1; NZ_CP016972.1.
DR   AlphaFoldDB; A5TZH1; -.
DR   SMR; A5TZH1; -.
DR   STRING; 419947.MRA_0450; -.
DR   EnsemblBacteria; ABQ72171; ABQ72171; MRA_0450.
DR   KEGG; mra:MRA_0450; -.
DR   eggNOG; COG1595; Bacteria.
DR   HOGENOM; CLU_047691_9_3_11; -.
DR   OMA; KGRFFTW; -.
DR   OrthoDB; 1992113at2; -.
DR   Proteomes; UP000001988; Chromosome.
DR   GO; GO:0003677; F:DNA binding; IEA:UniProtKB-KW.
DR   GO; GO:0016987; F:sigma factor activity; IEA:UniProtKB-KW.
DR   GO; GO:0006352; P:DNA-templated transcription, initiation; IEA:InterPro.
DR   Gene3D; 1.10.10.10; -; 1.
DR   InterPro; IPR039425; RNA_pol_sigma-70-like.
DR   InterPro; IPR014284; RNA_pol_sigma-70_dom.
DR   InterPro; IPR007627; RNA_pol_sigma70_r2.
DR   InterPro; IPR007630; RNA_pol_sigma70_r4.
DR   InterPro; IPR013325; RNA_pol_sigma_r2.
DR   InterPro; IPR013324; RNA_pol_sigma_r3/r4-like.
DR   InterPro; IPR036388; WH-like_DNA-bd_sf.
DR   PANTHER; PTHR43133; PTHR43133; 1.
DR   Pfam; PF04542; Sigma70_r2; 1.
DR   Pfam; PF04545; Sigma70_r4; 1.
DR   SUPFAM; SSF88659; SSF88659; 1.
DR   SUPFAM; SSF88946; SSF88946; 1.
DR   TIGRFAMs; TIGR02937; sigma70-ECF; 1.
PE   3: Inferred from homology;
KW   DNA-binding; Sigma factor; Transcription; Transcription regulation.
FT   CHAIN           1..187
FT                   /note="ECF RNA polymerase sigma factor SigK"
FT                   /id="PRO_0000313844"
FT   DNA_BIND        155..174
FT                   /note="H-T-H motif"
FT                   /evidence="ECO:0000250"
FT   REGION          30..96
FT                   /note="Sigma-70 factor domain-2"
FT   REGION          133..182
FT                   /note="Sigma-70 factor domain-4"
FT   MOTIF           53..56
FT                   /note="Interaction with polymerase core subunit RpoC"
SQ   SEQUENCE   187 AA;  21035 MW;  2156CEB813620F02 CRC64;
     MTGPPRLSSD LDALLRRVAG HDQAAFAEFY DHTKSRVYGL VMRVLRDTGY SEETTQEIYL
     EVWRNASEFD SAKGSALAWL LTMAHRRAVD RVRCEQAGNQ REVRYGAANV DPASDVVADL
     AIAGDERRRV TECLKALTDT QRQCIELAYY GGLTYVEVSR RLAANLSTIK SRMRDALRSL
     RNCLDVS