ID   CARA_MYXXA              Reviewed;         288 AA.
AC   Q50899;
DT   11-JUN-2014, integrated into UniProtKB/Swiss-Prot.
DT   01-NOV-1996, sequence version 1.
DT   25-MAY-2022, entry version 107.
DE   RecName: Full=HTH-type transcriptional repressor CarA;
GN   Name=carA;
OS   Myxococcus xanthus.
OC   Bacteria; Proteobacteria; Deltaproteobacteria; Myxococcales;
OC   Cystobacterineae; Myxococcaceae; Myxococcus.
OX   NCBI_TaxID=34;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RC   STRAIN=DK1050;
RX   PubMed=7588751; DOI=10.1111/j.1432-1033.1995.238_1.x;
RA   Botella J.A., Murillo F.J., Ruiz-Vazquez R.M.;
RT   "A cluster of structural and regulatory genes for light-induced
RT   carotenogenesis in Myxococcus xanthus.";
RL   Eur. J. Biochem. 233:238-248(1995).
RN   [2]
RP   FUNCTION, AND DISRUPTION PHENOTYPE.
RC   STRAIN=DK1050;
RX   PubMed=11914353; DOI=10.1128/jb.184.8.2215-2224.2002;
RA   Cervantes M., Murillo F.J.;
RT   "Role for vitamin B(12) in light induction of gene expression in the
RT   bacterium Myxococcus xanthus.";
RL   J. Bacteriol. 184:2215-2224(2002).
RN   [3]
RP   FUNCTION, DNA-BINDING, ACTIVITY REGULATION, SUBUNIT, INTERACTION WITH CARS,
RP   AND DOMAIN.
RC   STRAIN=DK1050;
RX   PubMed=11748235; DOI=10.1074/jbc.m110351200;
RA   Lopez-Rubio J.J., Elias-Arnanz M., Padmanabhan S., Murillo F.J.;
RT   "A repressor-antirepressor pair links two loci controlling light-induced
RT   carotenogenesis in Myxococcus xanthus.";
RL   J. Biol. Chem. 277:7262-7270(2002).
RN   [4]
RP   FUNCTION, DNA-BINDING, ACTIVITY REGULATION, DOMAIN, AND MUTAGENESIS OF
RP   174-HIS-HIS-175; HIS-175 AND 249-GLY-GLY-250.
RC   STRAIN=DK1050;
RX   PubMed=18315685; DOI=10.1111/j.1365-2958.2007.06086.x;
RA   Perez-Marin M.C., Padmanabhan S., Polanco M.C., Murillo F.J.,
RA   Elias-Arnanz M.;
RT   "Vitamin B12 partners the CarH repressor to downregulate a photoinducible
RT   promoter in Myxococcus xanthus.";
RL   Mol. Microbiol. 67:804-819(2008).
CC   -!- FUNCTION: Negative regulator of the carB operon in the dark. Binds
CC       specifically to the CarA operator, in the region around the carB
CC       promoter, which blocks access to the RNA polymerase.
CC       {ECO:0000269|PubMed:11748235, ECO:0000269|PubMed:11914353,
CC       ECO:0000269|PubMed:18315685}.
CC   -!- ACTIVITY REGULATION: Binds cobalamin (vitamin B12), but cobalamin is
CC       not required for CarA activity. Interaction with CarS prevents binding
CC       to DNA. {ECO:0000269|PubMed:11748235, ECO:0000269|PubMed:18315685}.
CC   -!- SUBUNIT: Forms homodimers or oligomers. Interacts with CarS.
CC       {ECO:0000269|PubMed:11748235}.
CC   -!- DOMAIN: The N-terminal region interacts with DNA and CarS, and the C-
CC       terminal region is involved in oligomerization and binding of
CC       cobalamin. {ECO:0000269|PubMed:11748235, ECO:0000269|PubMed:18315685}.
CC   -!- DISRUPTION PHENOTYPE: Deletion causes light-independent expression from
CC       the carB promoter. {ECO:0000269|PubMed:11914353}.
CC   -!- SIMILARITY: Belongs to the CarA/CarH B12-binding photoregulator family.
CC       {ECO:0000305}.
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DR   EMBL; Z21955; CAA79964.1; -; Genomic_DNA.
DR   PIR; S68197; S68197.
DR   RefSeq; WP_011551024.1; NZ_JABFNQ010000052.1.
DR   AlphaFoldDB; Q50899; -.
DR   BMRB; Q50899; -.
DR   SMR; Q50899; -.
DR   GeneID; 41358362; -.
DR   OMA; GDVRQEC; -.
DR   GO; GO:0031419; F:cobalamin binding; IEA:InterPro.
DR   GO; GO:0003677; F:DNA binding; IEA:UniProtKB-KW.
DR   GO; GO:0046872; F:metal ion binding; IEA:InterPro.
DR   GO; GO:0016117; P:carotenoid biosynthetic process; IEA:UniProtKB-KW.
DR   GO; GO:0006355; P:regulation of transcription, DNA-templated; IEA:InterPro.
DR   Gene3D; 1.10.1240.10; -; 1.
DR   InterPro; IPR006158; Cobalamin-bd.
DR   InterPro; IPR036724; Cobalamin-bd_sf.
DR   InterPro; IPR009061; DNA-bd_dom_put_sf.
DR   InterPro; IPR000551; MerR-type_HTH_dom.
DR   InterPro; IPR036594; Meth_synthase_dom.
DR   Pfam; PF02310; B12-binding; 1.
DR   Pfam; PF13411; MerR_1; 1.
DR   SMART; SM00422; HTH_MERR; 1.
DR   SUPFAM; SSF46955; SSF46955; 1.
DR   SUPFAM; SSF52242; SSF52242; 1.
DR   PROSITE; PS51332; B12_BINDING; 1.
DR   PROSITE; PS50937; HTH_MERR_2; 1.
PE   1: Evidence at protein level;
KW   Carotenoid biosynthesis; DNA-binding; Repressor; Transcription;
KW   Transcription regulation.
FT   CHAIN           1..288
FT                   /note="HTH-type transcriptional repressor CarA"
FT                   /id="PRO_0000429422"
FT   DOMAIN          2..73
FT                   /note="HTH merR-type"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00254"
FT   DOMAIN          162..288
FT                   /note="B12-binding"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00666"
FT   DNA_BIND        5..24
FT                   /note="H-T-H motif"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00254"
FT   MUTAGEN         174..175
FT                   /note="HH->AA: Does not affect activity."
FT                   /evidence="ECO:0000269|PubMed:18315685"
FT   MUTAGEN         175
FT                   /note="H->A: Does not affect activity."
FT                   /evidence="ECO:0000269|PubMed:18315685"
FT   MUTAGEN         249..250
FT                   /note="GG->AA: Does not affect activity."
FT                   /evidence="ECO:0000269|PubMed:18315685"
SQ   SEQUENCE   288 AA;  32008 MW;  5A0B7BD68090702A CRC64;
     MTLRIRTIAR MTGIREATLR AWERRYGFPR PLRSEGNNYR VYSREEVEAV RRVARLIQEE
     GLSVSEAIAQ VKTEPPREQP EAERLRERFW SSVGALEGDE VTRVLDDAQT VMDVEAYCDG
     FLLPLLREMG VRLDVAREHL ASALIRQRLR QVYDALSPAP AGPRALLACP SGDHHEGGLL
     VLGIHLKRKG WRVTMLGADT PAAALQGACV QVRPDVVALS FVRARAPEEF ASVLEDALRA
     CAPFPVVVGG LGAREHLKAI FSLGAQYAES SEELVAIWNQ VRNAQNRP