Intrinsic disorder in the partitioning protein KorB persists after co-operative complex formation with operator DNA and KorA
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Date
2017
Authors
Hyde, Eva I.
Callow, Philip
Rajasekar, Karthik V.
Timmins, Peter
Patel, Trushar R.
Siligardi, Giuliano
Hussain, Rohanah
White, Scott A.
Thomas, Christopher M.
Scott, David J.
Journal Title
Journal ISSN
Volume Title
Publisher
Portland Press
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 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.
Description
Open access article. Creative Commons Attribution International license (CC BY 4.0) applies
Keywords
Circular dichrosim , Intrinsically disordered proteins , Protein-DNA interactions , Protein-protein interactions , Small-angle scattering , Transcription regulation
Citation
Hyde, E. I., Callow, P., Rajasekar, K. V., Timmins, P., Patel, T. R., 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, 473(18), 3121-3135. https://doi.org/10.1042/BCJ20170281