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Full-Text Articles in Virology

Substrate Envelope-Designed Potent Hiv-1 Protease Inhibitors To Avoid Drug Resistance, Madhavi Nalam, Akbar Ali, G. S. Kiran Kumar Reddy, Hong Cao, Saima Anjum, Michael Altman, Nese Yilmaz, Bruce Tidor, Tariq Rana, Celia Schiffer Jan 2015

Substrate Envelope-Designed Potent Hiv-1 Protease Inhibitors To Avoid Drug Resistance, Madhavi Nalam, Akbar Ali, G. S. Kiran Kumar Reddy, Hong Cao, Saima Anjum, Michael Altman, Nese Yilmaz, Bruce Tidor, Tariq Rana, Celia Schiffer

Celia A. Schiffer

The rapid evolution of HIV under selective drug pressure has led to multidrug resistant (MDR) strains that evade standard therapies. We designed highly potent HIV-1 protease inhibitors (PIs) using the substrate envelope model, which confines inhibitors within the consensus volume of natural substrates, providing inhibitors less susceptible to resistance because a mutation affecting such inhibitors will simultaneously affect viral substrate processing. The designed PIs share a common chemical scaffold but utilize various moieties that optimally fill the substrate envelope, as confirmed by crystal structures. The designed PIs retain robust binding to MDR protease variants and display exceptional antiviral potencies against …


Structural And Thermodynamic Basis Of Amprenavir/Darunavir And Atazanavir Resistance In Hiv-1 Protease With Mutations At Residue 50, Seema Mittal, Rajintha Bandaranayake, Nancy King, Moses Prabu-Jeyabalan, Madhavi Nalam, Ellen Nalivaika, Nese Yilmaz, Celia Schiffer Jul 2013

Structural And Thermodynamic Basis Of Amprenavir/Darunavir And Atazanavir Resistance In Hiv-1 Protease With Mutations At Residue 50, Seema Mittal, Rajintha Bandaranayake, Nancy King, Moses Prabu-Jeyabalan, Madhavi Nalam, Ellen Nalivaika, Nese Yilmaz, Celia Schiffer

Celia A. Schiffer

Drug resistance occurs through a series of subtle changes that maintain substrate recognition but no longer permit inhibitor binding. In HIV-1 protease, mutations at I50 are associated with such subtle changes that confer differential resistance to specific inhibitors. Residue I50 is located at the protease flap tips, closing the active site upon ligand binding. Under selective drug pressure, I50V/L substitutions emerge in patients, compromising drug susceptibility and leading to treatment failure. The I50V substitution is often associated with amprenavir (APV) and darunavir (DRV) resistance, while the I50L substitution is observed in patients failing atazanavir (ATV) therapy. To explain how APV, …


Molecular Basis For Drug Resistance In Hiv-1 Protease, Akbar Ali, Rajintha M. Bandaranayake, Yufeng Cai, Nancy M. King, Madhavi Kolli, Seema Mittal, Jennifer E. Foulkes-Murzycki, Madhavi N. L. Nalam, Ellen A. Nalivaika, Aysegul Ozen, Moses Prabu-Jeyabalan, Kelly Thayer, Celia A. Schiffer Nov 2011

Molecular Basis For Drug Resistance In Hiv-1 Protease, Akbar Ali, Rajintha M. Bandaranayake, Yufeng Cai, Nancy M. King, Madhavi Kolli, Seema Mittal, Jennifer E. Foulkes-Murzycki, Madhavi N. L. Nalam, Ellen A. Nalivaika, Aysegul Ozen, Moses Prabu-Jeyabalan, Kelly Thayer, Celia A. Schiffer

Celia A. Schiffer

HIV-1 protease is one of the major antiviral targets in the treatment of patients infected with HIV-1. The nine FDA approved HIV-1 protease inhibitors were developed with extensive use of structure-based drug design, thus the atomic details of how the inhibitors bind are well characterized. From this structural understanding the molecular basis for drug resistance in HIV-1 protease can be elucidated. Selected mutations in response to therapy and diversity between clades in HIV-1 protease have altered the shape of the active site, potentially altered the dynamics and even altered the sequence of the cleavage sites in the Gag polyprotein. All …


Dynamics Of Preferential Substrate Recognition In Hiv-1 Protease: Redefining The Substrate Envelope, Aysegul Ozen, Turkan Haliloglu, Celia Schiffer Nov 2011

Dynamics Of Preferential Substrate Recognition In Hiv-1 Protease: Redefining The Substrate Envelope, Aysegul Ozen, Turkan Haliloglu, Celia Schiffer

Celia A. Schiffer

Human immunodeficiency virus type 1 (HIV-1) protease (PR) permits viral maturation by processing the gag and gag-pro-pol polyproteins. HIV-1 PR inhibitors (PIs) are used in combination antiviral therapy but the emergence of drug resistance has limited their efficacy. The rapid evolution of HIV-1 necessitates consideration of drug resistance in novel drug design. Drug-resistant HIV-1 PR variants no longer inhibited efficiently, continue to hydrolyze the natural viral substrates. Though highly diverse in sequence, the HIV-1 PR substrates bind in a conserved three-dimensional shape we termed the substrate envelope. Earlier, we showed that resistance mutations arise where PIs protrude beyond the substrate …


Evaluating The Substrate-Envelope Hypothesis: Structural Analysis Of Novel Hiv-1 Protease Inhibitors Designed To Be Robust Against Drug Resistance, Madhavi Nalam, Akbar Ali, Michael Altman, G. S. Kiran Kumar Reddy, Sripriya Chellappan, Visvaldas Kairys, Aysegul Ozen, Hong Cao, Michael Gilson, Bruce Tidor, Tariq Rana, Celia Schiffer Nov 2011

Evaluating The Substrate-Envelope Hypothesis: Structural Analysis Of Novel Hiv-1 Protease Inhibitors Designed To Be Robust Against Drug Resistance, Madhavi Nalam, Akbar Ali, Michael Altman, G. S. Kiran Kumar Reddy, Sripriya Chellappan, Visvaldas Kairys, Aysegul Ozen, Hong Cao, Michael Gilson, Bruce Tidor, Tariq Rana, Celia Schiffer

Celia A. Schiffer

Drug resistance mutations in HIV-1 protease selectively alter inhibitor binding without significantly affecting substrate recognition and cleavage. This alteration in molecular recognition led us to develop the substrate-envelope hypothesis which predicts that HIV-1 protease inhibitors that fit within the overlapping consensus volume of the substrates are less likely to be susceptible to drug-resistant mutations, as a mutation impacting such inhibitors would simultaneously impact the processing of substrates. To evaluate this hypothesis, over 130 HIV-1 protease inhibitors were designed and synthesized using three different approaches with and without substrate-envelope constraints. A subset of 16 representative inhibitors with binding affinities to wild-type …