PM to μM: Elucidating the Interdependence of Highly Resistant HIV‐1 Proteases

Abstract

HIV‐1 protease is an ideal model system to investigate the molecular mechanisms of resistance against small molecule inhibitors. Darunavir (DRV) binds WT HIV‐1 protease with a potency of <5 pM. We have identified a protease variant that loses potency to DRV 150,000‐fold, with 11 mutations in and outside the active site. Traditionally, active site mutations were thought to confer resistance while other “secondary” mutations compensate for losses in enzymatic activity. To elucidate the molecular mechanisms and roles of these selected mutations in DRV resistance, we used a multidisciplinary approach, combining enzymatic assays, crystallography, and molecular dynamics simulations. Analysis of protease variants with 1, 2, 4, 8, 9, 10 and 11 mutations showed that the primary active site mutations caused ~50‐fold loss in potency (2 mutations), while distal mutations outside the active site further decreased DRV potency from 13 nM (8 mutations) to 760 nM (11 mutations). Structural analysis indicates distal mutations induce subtle changes that are dynamically propagated through the protease. Our results reveal that many of the changes remote from the active site directly and dramatically impact the potency of the inhibitor. These mechanisms of resistance are likely applicable to many other quickly evolving drug targets and these insights have implications for the design of more robust inhibitors.Support or Funding InformationThis work was supported in part by a grant from the National Institute of General Medical Sciences, National Institutes of Health (P01‐GM109767)This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.