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

Hyde, Eva I. and Callow, Phillip and Rajasekar, Karthik V. and timmins, Peter and Patel, Trushar Patel and Siligardi, Giuliano and Hussain, Rohanah and White, Scott A. and Thomas, Christopher M. and Scott, David J. (2017) Intrinsic disorder in the partitioning protein KorB persists after co-operative complex formation with operator DNA and KorA. Biochemical Journal, 474 (18). pp. 3121-3135. ISSN 0264-6021

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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 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 the 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 betweenthe 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.

Item Type: Article
Additional Information: This work is based in 10 years of data acquisition that started in 2007 at the ILL in Grenoble. Data was acquired at the ILL and ISIS (Oxfordshire) neutron sources, with circular dichroism data obtained at B23 of the Diamond Light Source. NMR data was obtained at the Henry Wellcome NMR centre at the University of Birmingham.
Keywords: circular dichroism; intrinsically disordered regions; small-angle neutron scattering experiments; small-angle X-ray scattering;
Schools/Departments: University of Nottingham, UK > Faculty of Science > School of Biosciences
Identification Number: 10.1042/BCJ20170281
Depositing User: Scott, David
Date Deposited: 08 Sep 2017 10:05
Last Modified: 08 Sep 2017 10:10
URI: http://eprints.nottingham.ac.uk/id/eprint/45548

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