5CM3

Crystal Structure of KorA, a plasmid-encoded, global transcription regulator

Summary for 5CM3

• Entry DOI: 10.2210/pdb5cm3/pdb
• Descriptor: TrfB transcriptional repressor protein, 5'-D(CP*CP*AP*AP*GP*TP*TP*TP*AP*GP*CP*TP*AP*AP*AP*CP*TP*TP*GP*GP*)-3' (3 entities in total)
• Functional Keywords: helix-turn-helix, dna complex, transcription
• Biological source: Escherichia coli; More
• Total number of polymer chains: 4
• Total formula weight: 33880.61

Authors

White, S.A.,Hyde, E.I.,Rajasekar, K.V. (deposition date: 2015-07-16, release date: 2016-04-06, Last modification date: 2024-01-10)

Primary citation

Rajasekar, K.V.,Lovering, A.L.,Dancea, F.,Scott, D.J.,Harris, S.A.,Bingle, L.E.,Roessle, M.,Thomas, C.M.,Hyde, E.I.,White, S.A.
Flexibility of KorA, a plasmid-encoded, global transcription regulator, in the presence and the absence of its operator.
Nucleic Acids Res., 44:4947-4956, 2016

PubMed Abstract: The IncP (Incompatibility group P) plasmids are important carriers in the spread of antibiotic resistance across Gram-negative bacteria. Gene expression in the IncP-1 plasmids is stringently controlled by a network of four global repressors, KorA, KorB, TrbA and KorC interacting cooperatively. Intriguingly, KorA and KorB can act as co-repressors at varying distances between their operators, even when they are moved to be on opposite sides of the DNA. KorA is a homodimer with the 101-amino acid subunits, folding into an N-terminal DNA-binding domain and a C-terminal dimerization domain. In this study, we have determined the structures of the free KorA repressor and two complexes each bound to a 20-bp palindromic DNA duplex containing its consensus operator sequence. Using a combination of X-ray crystallography, nuclear magnetic resonance spectroscopy, SAXS and molecular dynamics calculations, we show that the linker between the two domains is very flexible and the protein remains highly mobile in the presence of DNA. This flexibility allows the DNA-binding domains of the dimer to straddle the operator DNA on binding and is likely to be important in cooperative binding to KorB. Unexpectedly, the C-terminal domain of KorA is structurally similar to the dimerization domain of the tumour suppressor p53.

PubMed: 27016739
DOI: 10.1093/nar/gkw191

Experimental method

X-RAY DIFFRACTION (2.302 Å)