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

Hyde, Eva I.; Callow, Phillip; Rajasekar, Karthik V.; Timmins, Peter; Patel, Trushar Patel; Siligardi, Giuliano; Hussain, Rohanah; White, Scott A.; Thomas, Christopher M.; Scott, David J.

Abstract

© 2017 The Author(s). 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 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.

Citation

Hyde, E. I., Callow, P., Rajasekar, K. V., Timmins, P., Patel, T. P., Siligardi, G., Hussain, R., White, S. A., Thomas, C. M., & Scott, D. J. (2017). Intrinsic disorder in the partitioning protein KorB persists after co-operative complex formation with operator DNA and KorA. Biochemical Journal, 474(18), 3121-3135. https://doi.org/10.1042/BCJ20170281

• Journal Article Type: Article
• Acceptance Date: Jul 31, 2017
• Online Publication Date: Jul 31, 2017
• Publication Date: Aug 31, 2017
• Deposit Date: Sep 8, 2017
• Publicly Available Date: Sep 8, 2017
• Journal: Biochemical Journal
• Print ISSN: 0264-6021
• Electronic ISSN: 1470-8728
• Publisher: Portland Press
• Peer Reviewed: Peer Reviewed
• Volume: 474
• Issue: 18
• Pages: 3121-3135
• DOI: https://doi.org/10.1042/BCJ20170281
• Keywords: Cell Biology; Biochemistry; Molecular Biology
• Public URL: https://nottingham-repository.worktribe.com/output/880585
• Publisher URL: http://www.biochemj.org/content/474/18/3121
• 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.
• Contract Date: Sep 8, 2017