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Intrinsic disorder in the partitioning protein KorB persists after cooperative complex formation with operator DNA and KorA

DOI: 10.1042/BCJ20170281 DOI Help

Authors: Eva Hyde (University of Birmingham) , Phillip Callow (Institut Laue Langevin) , Karthik V. Rajasekar (University of Birmingham) , Peter Timmins (Institut Laue Langevin) , Trushar R. Patel (University of Birmingham) , Giuliano Siligardi (Diamond Light Source) , Rohanah Hussain (Diamond Light Source) , Scott White (University of Birmingham) , Christopher M. Thomas (University of Birmingham) , David J. Scott (University of Nottingham; ISIS Neutron and Muon Spallation Source and Research Complex at Harwell)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Biochemical Journal

State: Published (Approved)
Published: July 2017
Diamond Proposal Number(s): 14894 , 16440

Open Access Open Access

Abstract: The ParB protein, KorB, from the RK2 plasmid is required for DNA partitioning and transcriptional repression. It acts co-operatively with other proteins, including the repressor KorA. Like many multifunctional proteins, KorB contains regions of intrinsically disordered structure, existing in a large ensemble of interconverting conformations. Using NMR spectroscopy, circular dichroism, and small angle neutron scattering, we have studied KorB selectively within its binary complexes with KorA and DNA, and within the ternary KorA/KorB/DNA complex. The bound KorB protein remains disordered, with a mobile C-terminal domain and no changes in secondary structure but increases in the radius of gyration on complex formation. Comparison of wild type KorB with an N-terminal deletion mutant allows a model of the ensemble average distances between the domains when bound to DNA. We propose that the positive co-operativity between KorB, KorA and DNA results from conformational restriction of KorB on binding each partner, while maintaining disorder.

Journal Keywords: ParB; DNA partitioning; intrinsic disorder; co-operativity; KorB-KorA-DNA; 36 complex; small angle neutron scattering; contrast matching

Subject Areas: Biology and Bio-materials

Instruments: B23-Circular Dichroism

Other Facilities: ESRF; DESY

Added On: 03/08/2017 09:03


Discipline Tags:

Structural biology Biophysics Life Sciences & Biotech

Technical Tags:

Spectroscopy Circular Dichroism (CD)