Mechanism of SAMT analog inactivation of HIV-1 Gag polyprotein

Authors

• EL Paine
• KM Rosenker
• HD Tagad
• MT Scerba
• L Deshmukh
• DE Ott
• DH Appella
• LM Miller Jenkins

Abstract

Although antiretroviral therapy has advanced, there remains a critical need for new therapeutics, especially those targeted at resistant strains of HIV. The Gag polyprotein, and in particular its constituent nucleocapsid protein, NCp7, represents a prime target for antiretroviral inhibition. NCp7 is composed of two highly conserved zinc-binding domains and plays multiple roles throughout the virus replication cycle. We have developed a class of small molecule inhibitors of NCp7, based upon an S-acyl-2-mercaptobenzamide thioester (SAMT) scaffold, that covalently modify the zinc-binding domains of NCp7 in vitro and in cells. These compounds display potent antiviral activity without evidence of cytotoxicity in cell models, ex vivo cervical explants, and in animal models. We investigated the mechanism of viral inactivation of the Gag polyprotein both in vitro and in virus-like particles (VLPs) released from cells. We utilized mass spectrometry and NMR spectroscopy to characterize the covalent SAMT reaction sites within the Gag polyprotein. Our results indicate that reaction occurs first within the NCp7 domain, but that sites within both matrix and capsid are also modified. These results represent an increased understanding of the mechanism of SAMT activity and will help to develop better inhibitors.

Scientific Focus Area: Cell Biology

This page was last updated on Friday, March 26, 2021