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Full-Text Articles in Molecular Biology
A Sensitive Assay Using A Native Protein Substrate For Screening Hiv-1 Maturation Inhibitors Targeting The Protease Cleavage Site Between The Matrix And Capsid, Sook-Kyung Lee, Nancy Cheng, Emily Hull-Ryde, Marc Potempa, Celia Schiffer, William Janzen, Ronald Swanstrom
A Sensitive Assay Using A Native Protein Substrate For Screening Hiv-1 Maturation Inhibitors Targeting The Protease Cleavage Site Between The Matrix And Capsid, Sook-Kyung Lee, Nancy Cheng, Emily Hull-Ryde, Marc Potempa, Celia Schiffer, William Janzen, Ronald Swanstrom
Celia A. Schiffer
The matrix/capsid processing site in the HIV-1 Gag precursor is likely the most sensitive target to inhibit HIV-1 replication. We have previously shown that modest incomplete processing at the site leads to a complete loss of virion infectivity. In the study presented here, a sensitive assay based on fluorescence polarization that can monitor cleavage at the MA/CA site in the context of the folded protein substrate is described. The substrate, an MA/CA fusion protein, was labeled with the fluorescein-based FlAsH (fluorescein arsenical hairpin) reagent that binds to a tetracysteine motif (CCGPCC) that was introduced within the N-terminal domain of CA. …
Interview With Celia Schiffer, Celia Schiffer
Interview With Celia Schiffer, Celia Schiffer
Celia A. Schiffer
Celia Schiffer, a Professor in Biochemistry and Molecular Pharmacology; a former Director of UMass Center for AIDS Research; and a Founder and Co-Director for the Institute for Drug Resistance (University of Massachusetts Medical School, MA, USA). Schiffer has an undergraduate degree in physics from the University of Chicago, with a PhD in biophysics from University of California, San Francisco (CA, USA). She was a postdoctoral associate first at the ETH in Zurich and then at Genentech in San Francisco. Schiffer has published more than 100 peer reviewed journal articles. Her laboratory primarily uses structural biology, biophysical and chemistry techniques to …
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
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 …
Decomposing The Energetic Impact Of Drug-Resistant Mutations: The Example Of Hiv-1 Protease-Drv Binding, Yufeng Cai, Celia Schiffer
Decomposing The Energetic Impact Of Drug-Resistant Mutations: The Example Of Hiv-1 Protease-Drv Binding, Yufeng Cai, Celia Schiffer
Celia A. Schiffer
HIV-1 protease is a major drug target for AIDS therapy. With the appearance of drug-resistant HIV-1 protease variants, understanding the mechanism of drug resistance becomes critical for rational drug design. Computational methods can provide more details about inhibitor-protease binding than crystallography and isothermal titration calorimetry. The latest FDA-approved HIV-1 protease inhibitor is Darunavir (DRV). Herein, each DRV atom is evaluated by free energy component analysis for its contribution to the binding affinity with wild-type protease and ACT, a drug-resistant variant. This information can contribute to the rational design of new HIV-1 protease inhibitors.
Context Surrounding Processing Sites Is Crucial In Determining Cleavage Rate Of A Subset Of Processing Sites In Hiv-1 Gag And Gag-Pro-Pol Polyprotein Precursors By Viral Protease, Sook-Kyung Lee, Marc Potempa, Madhavi Kolli, Aysegul Ozen, Celia Schiffer, Ronald Swanstrom
Context Surrounding Processing Sites Is Crucial In Determining Cleavage Rate Of A Subset Of Processing Sites In Hiv-1 Gag And Gag-Pro-Pol Polyprotein Precursors By Viral Protease, Sook-Kyung Lee, Marc Potempa, Madhavi Kolli, Aysegul Ozen, Celia Schiffer, Ronald Swanstrom
Celia A. Schiffer
Processing of the human immunodeficiency virus type 1 (HIV-1) Gag and Gag-Pro-Pol polyproteins by the HIV-1 protease (PR) is essential for the production of infectious particles. However, the determinants governing the rates of processing of these substrates are not clearly understood. We studied the effect of substrate context on processing by utilizing a novel protease assay in which a substrate containing HIV-1 matrix (MA) and the N-terminal domain of capsid (CA) is labeled with a FlAsH (fluorescein arsenical hairpin) reagent. When the seven cleavage sites within the Gag and Gag-Pro-Pol polyproteins were placed at the MA/CA site, the rates of …
Dynamics Of Preferential Substrate Recognition In Hiv-1 Protease: Redefining The Substrate Envelope, Aysegul Ozen, Turkan Haliloglu, Celia Schiffer
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
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 …