Abstract
Defining mechanisms of direct-acting antivirals facilitates drug development and our understanding of virus function. Heteroaryldihydropyrimidines (HAPs) inappropriately activate assembly of hepatitis B virus (HBV) core protein (Cp), suppressing formation of virions. We examined a fluorophore-labeled HAP, HAP-TAMRA. HAP-TAMRA induced Cp assembly and also bound pre-assembled capsids. Kinetic and spectroscopic studies imply that HAP-binding sites are usually not available but are bound cooperatively. Using cryo-EM, we observed that HAP-TAMRA asymmetrically deformed capsids, creating a heterogeneous array of sharp angles, flat regions, and outright breaks. To achieve high resolution reconstruction (<4 Å), we introduced a disulfide crosslink that rescued particle symmetry. We deduced that HAP-TAMRA caused quasi-sixfold vertices to become flatter and fivefold more angular. This transition led to asymmetric faceting. That a disordered crosslink could rescue symmetry implies that capsids have tensegrity properties. Capsid distortion and disruption is a new mechanism by which molecules like the HAPs can block HBV infection.
Highlights
An estimated 240 million people suffer from chronic hepatitis B virus (HBV); infection is most often acquired in early childhood
HAP-TAMRA is a probe of core protein and Core protein Allosteric Modulators (CpAMs) interaction
To verify the activity of HAP-TAMRA, we examined its effect on purified dimeric assembly domain, Cp149
Summary
An estimated 240 million people suffer from chronic hepatitis B virus (HBV); infection is most often acquired in early childhood. Chronic HBV can lead to liver disease including liver failure, cirrhosis, and hepatocellular carcinoma, contributing to more than 700,000 deaths each year (Gish et al, 2015). A vaccine directed against surface protein is preventative but not therapeutic. Entry inhibitors prevent new infection but are unlikely to affect maintenance of a chronic infection (Volz et al, 2013). Reverse transcriptase inhibitors directed against the viral polymerase suppress viremia and improve liver health, but even after years of treatment are rarely curative (Gish et al, 2007; Shi et al, 2015). The viral core protein (Cp) has become an important target for developing direct-acting antivirals (DAAs) (Zlotnick et al, 2015)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
