The objective of this study is to determine the molecular determinants of synergistic inhibition of the Hepatitis C virus (HCV) polymerase when multiple allosteric inhibitors bind simultaneously to the enzyme. HCV affects close to 200 million people worldwide, making it a global health concern. The HCV polymerase (gene product NS5B) is a vital component of viral replication and has no known mammalian homolog, making it a promising target for antiviral therapeutics. Unfortunately, the low fidelity of NS5B results i quasi-species of the virus, leading to multiple enzyme variants and making it difficult to target the HCV NS5B with single inhibitors. Recent studies show that the use of multiple allosteric inhibitors has a synergistic inhibitory effect on NS5B. However, the mechanism by which this synergistic inhibition is unclear. Here, we propose to employ computational and experimental approaches to determine the changes in both dynamic and thermodynamic properties that are critical for mediation of the synergistic inhibition of NS5B. Such approaches will provide us with information on how inhibitor-binding impacts the motions of protein residues and the enzyme free energy landscape resulting to induce synergistic inhibition of NS5B. Furthermore, mechanistic details revealed by our study on NS5B may be relevant to the areas of drug discovery, regulation of metabolic pathways, and other signal transduction processes.

Public Health Relevance

An understanding of the mechanistic events necessary for synergistic inhibition of the Hepatitis C virus (HCV) polymerase will aid in the development and discovery of more effective inhibitors for the enzyme. There is a dire need for more molecules that could serve as the basis for HCV treatments, as it affects millions of people worldwide (of which about 4 million are Americans) and there are limited approved treatments for this infection. Furthermore, this study will yield insights regarding the molecular mechanisms of synergistic inhibition, a property that is important in the inhibition of NS5B and other disease-related multi-domain protein targets.

National Institute of Health (NIH)
National Institute of General Medical Sciences (NIGMS)
Predoctoral Individual National Research Service Award (F31)
Project #
Application #
Study Section
Special Emphasis Panel (ZRG1)
Program Officer
Gaillard, Shawn R
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
University of Maryland Balt CO Campus
Schools of Arts and Sciences
United States
Zip Code
Brown, Jodian A; Espiritu, Marie V; Abraham, Joel et al. (2016) Computational predictions suggest that structural similarity in viral polymerases may lead to comparable allosteric binding sites. Virus Res 222:80-93
Davis, Brittny C; Brown, Jodian A; Thorpe, Ian F (2015) Allosteric inhibitors have distinct effects, but also common modes of action, in the HCV polymerase. Biophys J 108:1785-1795
Brown, Jodian A; Thorpe, Ian F (2015) Dual Allosteric Inhibitors Jointly Modulate Protein Structure and Dynamics in the Hepatitis C Virus Polymerase. Biochemistry 54:4131-41
Brown, Jodian A; Thorpe, Ian F (2015) 178 Dual allosteric inhibitors jointly modulate structure and dynamics in the Hepatitis C Virus polymerase. J Biomol Struct Dyn 33 Suppl 1:116-7