Molecular Mechanisms of Resistance and Structure-Based Drug Design in Homodimeric Viral Proteases
AuthorsLockbaum, Gordon J.
Faculty AdvisorCelia A. Schiffer
Academic ProgramBiochemistry and Molecular Pharmacology
UMass Chan AffiliationsBiochemistry and Molecular Pharmacology
Document TypeDoctoral Dissertation
Structure-Based Drug Design
MetadataShow full item record
AbstractDrug resistance is a global health threat costing society billions of dollars and impacting millions of lives each year. Current drug design strategies are inadequate because they focus on disrupting target activity and not restricting the evolutionary pathways to resistance. Improved strategies would exploit the structural and dynamic changes in the enzyme–inhibitor system integrating data from many inhibitors and variants. Using HIV-1 protease as a model system, I aimed to elucidate the underlying resistance mechanisms, characterize conserved protease-inhibitor interactions, and generate more robust inhibitors by applying these insights. For primary mechanisms of resistance, comparing interactions at the protease–inhibitor interface showed how specific modifications affected potency. For mutations distal to the active site, molecular dynamics simulations were necessary to elucidate how changes propagated to reduce inhibitor binding. These insights informed inhibitor design to improve potency against highly resistant variants by optimizing hydrogen bonding. A series of hybrid inhibitors was also designed that showed excellent potency by combining key moieties of multiple FDA-approved inhibitors. I characterized the structural basis for alterations in binding affinity in HIV-1 protease both from mutations and inhibitors. I applied these strategies to HTLV-1 protease, a potential drug target. I identified the HIV-1 inhibitor darunavir as a viable scaffold and evaluated analogues, leading to a low-nanomolar compound with potential for optimization. Hopefully, insights from this thesis will lead to the development of potent HTLV-1 protease inhibitors. More broadly, these inhibitor design strategies are applicable to other rapidly evolving targets, thereby reducing drug resistance rates in the future.
Permanent Link to this Itemhttp://hdl.handle.net/20.500.14038/31296
RightsCopyright is held by the author, with all rights reserved.
Showing items related by title, author, creator and subject.
TMC310911, a Novel Human Immunodeficiency Virus Type 1 Protease Inhibitor, Shows In Vitro an Improved Resistance Profile and Higher Genetic Barrier to Resistance Compared with Current Protease InhibitorsDierynck, Inge; Van Marck, Herwig; Van Ginderen, Marcia; Jonckers, Tim H. M.; Nalam, Madhavi N. L.; Schiffer, Celia A.; Raoof, Araz; Kraus, Guenter; Picchio, Gaston (2011-12-08)TMC310911 is a novel human immunodeficiency virus type 1 (HIV-1) protease inhibitor (PI) structurally closely related to darunavir (DRV) but with improved virological characteristics. TMC310911 has potent activity against wild-type (WT) HIV-1 (median 50% effective concentration [EC(50)], 14 nM) and a wide spectrum of recombinant HIV-1 clinical isolates, including multiple-PI-resistant strains with decreased susceptibility to currently approved PIs (fold change [FC] in EC(50), >10). For a panel of 2,011 recombinant clinical isolates with decreased susceptibility to at least one of the currently approved PIs, the FC in TMC310911 EC(50) was
Pan-3C Protease Inhibitor Rupintrivir Binds SARS-CoV-2 Main Protease in a Unique Binding ModeLockbaum, Gordon J.; Henes, Mina; Lee, Jeong Min.; Timm, Jennifer; Nalivaika, Ellen A.; Thompson, Paul R; Yilmaz, Nese Kurt; Schiffer, Celia A. (2021-10-05)Rupintrivir targets the 3C cysteine proteases of the picornaviridae family, which includes rhinoviruses and enteroviruses that cause a range of human diseases. Despite being a pan-3C protease inhibitor, rupintrivir activity is extremely weak against the homologous 3C-like protease of SARS-CoV-2. In this study, the crystal structures of rupintrivir were determined bound to enterovirus 68 (EV68) 3C protease and the 3C-like main protease (M(pro)) from SARS-CoV-2. While the EV68 3C protease-rupintrivir structure was similar to previously determined complexes with other picornavirus 3C proteases, rupintrivir bound in a unique conformation to the active site of SARS-CoV-2 M(pro) splitting the catalytic cysteine and histidine residues. This bifurcation of the catalytic dyad may provide a novel approach for inhibiting cysteine proteases.
Association of a novel human immunodeficiency virus type 1 protease substrate cleft mutation, L23I, with protease inhibitor therapy and in vitro drug resistanceJohnston, Elizabeth; Winters, Mark A.; Rhee, Soo-Yon; Merigan, Thomas C.; Schiffer, Celia A.; Shafer, Robert W. (2004-11-25)We observed a previously uncharacterized mutation in the protease substrate cleft, L23I, in 31 of 4,303 persons undergoing human immunodeficiency virus type 1 genotypic resistance testing. In combination with V82I, L23I was associated with a sevenfold reduction in nelfinavir susceptibility and a decrease in replication capacity. In combination with other drug resistance mutations, L23I was associated with multidrug resistance and a compensatory increase in replication capacity.