Download MendeleyUnfolding the HIV-1 reverse transcriptase RNase H domain - how to lose a molecular tug-of-war.
Zheng, X., Pedersen, L.C., Gabel, S.A., Mueller, G.A., DeRose, E.F., London, R.E.(2016) Nucleic Acids Res 44: 1776-1788
- PubMed: 26773054
- DOI: https://doi.org/10.1093/nar/gkv1538
- Primary Citation of Related Structures:
5DZM - PubMed Abstract:
Formation of the mature HIV-1 reverse transcriptase (RT) p66/p51 heterodimer requires subunit-specific processing of the p66/p66' homodimer precursor. Since the ribonuclease H (RH) domain contains an occult cleavage site located near its center, cleavage must occur either prior to folding or subsequent to unfolding. Recent NMR studies have identified a slow, subunit-specific RH domain unfolding process proposed to result from a residue tug-of-war between the polymerase and RH domains on the functionally inactive, p66' subunit. Here, we describe a structural comparison of the isolated RH domain with a domain swapped RH dimer that reveals several intrinsically destabilizing characteristics of the isolated domain that facilitate excursions of Tyr427 from its binding pocket and separation of helices B and D. These studies provide independent support for the subunit-selective RH domain unfolding pathway in which instability of the Tyr427 binding pocket facilitates its release followed by domain transfer, acting as a trigger for further RH domain destabilization and subsequent unfolding. As further support for this pathway, NMR studies demonstrate that addition of an RH active site-directed isoquinolone ligand retards the subunit-selective RH' domain unfolding behavior of the p66/p66' homodimer. This study demonstrates the feasibility of directly targeting RT maturation with therapeutics.
Organizational Affiliation:
Genome Integrity and Structural Biology Laboratory, National Institute of Environmental health Sciences, NIH, Research Triangle Park, NC 27709, USA.
