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McbR DNA-binding transcriptional dual regulator

Synonyms: McbR
McbR is a member of the FadR C-terminal domain (FCD) family of the GntR superfamily of transcriptional regulators [3, 4, 5] It binds as a dimer to its operator site via its winged helix domains [Xu01]. It is probable that McbR binds to DNA as a dimer [Beraud10].
Residues of McbR that could interact with DNA-binding sites are Lys38 with the α2-helix and Thr49 with the α3-helix. In addition, Arg34 and Arg52 are also important for the DNA-binding site [3].
McbR (YncC) regulates biofilm formation and mucoidity by repressing expression of mcbA (ybiM) [1] McbA belongs to the YhcN family of periplasmic proteins and is induced by the quorum-sensing signal autoinducer 2 (AI-2) [6, 7]
McbR is negatively autoregulated and, in addition, repressed by YgiV [1] Expression of mcbR is induced by overexpression of the lsr operon regulators LsrR and LsrK, the quorum-sensing regulator MqsR, and the AI-2 exporter TqsA [1]
McbR carries a helix-turn-helix DNA-binding motif (aa 37-56) and represses transcription of mcbA by binding to the promoter region of mcbA [1]
McbR: MqsR-controlled colanic acid and biofilm Regulator [1]
The crystal structure of McbR has been determined to 2.1 Å [3]
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Transcription factor      
TF conformation(s):
Name Conformation Type TF-Effector Interaction Type Apo/Holo Conformation Evidence (Confirmed, Strong, Weak) References
McbR     nd nd
Evolutionary Family: GntR
Connectivity class: Local Regulator
Gene name: mcbR
  Genome position: 1520262-1520927
  Length: 666 bp / 221 aa
Operon name: mcbR
TU(s) encoding the TF:
Transcription unit        Promoter

Regulated gene(s) mcbA, yciE, yciF, yciG
Multifun term(s) of regulated gene(s)
cell structure (1)
Regulated operon(s) mcbA, yciGFE
First gene in the operon(s) mcbA, yciG, yciG
Simple and complex regulons H-NS,McbR
Simple and complex regulatory phrases Regulatory phrase (List of promoters regulated by the phrase)

Transcription factor binding sites (TFBSs) arrangements       

  Functional conformation Function Promoter Sigma factor Central Rel-Pos Distance to first Gene Genes Sequence LeftPos RightPos Evidence (Confirmed, Strong, Weak) References
  McbR repressor mcbAp5 Sigma70 nd nd mcbA nd nd [BPP], [GEA] [1]
  McbR activator yciGp Sigma38 -88.5 -145.5 yciG, yciF, yciE
1316170 1316191 [BPP], [GEA] [2], [3]
  McbR activator yciGp Sigma38 -67.5 -124.5 yciG, yciF, yciE
1316149 1316170 [BPP], [GEA] [2], [3]

Evolutionary conservation of regulatory elements    
     Note: Evolutionary conservation of regulatory interactions and promoters is limited to gammaproteobacteria.
Promoter-target gene evolutionary conservation


 [BPP] Binding of purified proteins

 [GEA] Gene expression analysis


 [1] Zhang XS., Garcia-Contreras R., Wood TK., 2008, Escherichia coli transcription factor YncC (McbR) regulates colanic acid and biofilm formation by repressing expression of periplasmic protein YbiM (McbA)., ISME J. 2(6):615-31

 [2] Beraud M., Kolb A., Monteil V., D'Alayer J., Norel F., 2010, A proteomic analysis reveals differential regulation of the ¿¿(S)-dependent yciGFE(katN) locus by YncC and H-NS in Salmonella and Escherichia coli K-12., Mol Cell Proteomics. 9(12):2601-16

 [3] Lord DM., Uzgoren Baran A., Soo VW., Wood TK., Peti W., Page R., 2014, McbR/YncC: implications for the mechanism of ligand and DNA binding by a bacterial GntR transcriptional regulator involved in biofilm formation., Biochemistry. 53(46):7223-31

 [4] Rigali S., Derouaux A., Giannotta F., Dusart J., 2002, Subdivision of the helix-turn-helix GntR family of bacterial regulators in the FadR, HutC, MocR, and YtrA subfamilies., J Biol Chem. 277(15):12507-15

 [5] Hoskisson PA., Rigali S., 2009, Chapter 1: Variation in form and function the helix-turn-helix regulators of the GntR superfamily., Adv Appl Microbiol. 69:1-22

 [6] DeLisa MP., Wu CF., Wang L., Valdes JJ., Bentley WE., 2001, DNA microarray-based identification of genes controlled by autoinducer 2-stimulated quorum sensing in Escherichia coli., J Bacteriol. 183(18):5239-47

 [7] Rudd KE., Humphery-Smith I., Wasinger VC., Bairoch A., 1998, Low molecular weight proteins: a challenge for post-genomic research., Electrophoresis. 19(4):536-44