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Full-Text Articles in Biochemistry, Biophysics, and Structural Biology

Dengue Virus Ns2b/Ns3 Protease Inhibitors Exploiting The Prime Side, Kuan-Hung Lin, Akbar Ali, Linah Rusere, Djade I. Soumana, Nese Kurt Yilmaz, Celia A. Schiffer Jul 2017

Dengue Virus Ns2b/Ns3 Protease Inhibitors Exploiting The Prime Side, Kuan-Hung Lin, Akbar Ali, Linah Rusere, Djade I. Soumana, Nese Kurt Yilmaz, Celia A. Schiffer

Celia A. Schiffer

The mosquito-transmitted dengue virus (DENV) infects millions of people in tropical and subtropical regions. Maturation of DENV particles requires proper cleavage of the viral polyprotein, including processing of 8 of the 13 substrate cleavage sites by dengue virus NS2B/NS3 protease. With no available direct-acting antiviral targeting DENV, NS2/NS3 protease is a promising target for inhibitor design. Current design efforts focus on the nonprime side of the DENV protease active site, resulting in highly hydrophilic and nonspecific scaffolds. However, the prime side also significantly modulates DENV protease binding affinity, as revealed by engineering the binding loop of aprotinin, a small protein …


Structural And Molecular Analysis Of A Protective Epitope Of Lyme Disease Antigen Ospa And Antibody Interactions, Shivender Shandilya, Nese Kurt Yilmaz, Ejemel Monir, Andrew Sadowski, William D. Thomas, Mark S. Klempner, Celia A. Schiffer, Yan Wang Aug 2016

Structural And Molecular Analysis Of A Protective Epitope Of Lyme Disease Antigen Ospa And Antibody Interactions, Shivender Shandilya, Nese Kurt Yilmaz, Ejemel Monir, Andrew Sadowski, William D. Thomas, Mark S. Klempner, Celia A. Schiffer, Yan Wang

Celia A. Schiffer

The murine monoclonal antibody LA-2 recognizes a clinically protective epitope on outer surface protein (OspA) of Borrelia burgdorferi, the causative agent of Lyme disease in North America. Human antibody equivalence to LA-2 is the best serologic correlate of protective antibody responses following OspA vaccination. Understanding the structural and functional basis of the LA-2 protective epitope is important for developing OspA-based vaccines and discovering prophylactic antibodies against Lyme disease. Here, we present a detailed structure-based analysis of the LA-2/OspA interaction interface and identification of residues mediating antibody recognition. Mutations were introduced into both OspA and LA-2 based on computational predictions on …


Structural Basis For Mutation-Induced Destabilization Of Profilin 1 In Als, Sivakumar Boopathy, Tania Silvas, Maeve Tischbein, Silvia Jansen, Shivender Shandilya, Jill Zitzewitz, John Landers, Bruce Goode, Celia Schiffer, Daryl Bosco Jan 2016

Structural Basis For Mutation-Induced Destabilization Of Profilin 1 In Als, Sivakumar Boopathy, Tania Silvas, Maeve Tischbein, Silvia Jansen, Shivender Shandilya, Jill Zitzewitz, John Landers, Bruce Goode, Celia Schiffer, Daryl Bosco

Celia A. Schiffer

Mutations in profilin 1 (PFN1) are associated with amyotrophic lateral sclerosis (ALS); however, the pathological mechanism of PFN1 in this fatal disease is unknown. We demonstrate that ALS-linked mutations severely destabilize the native conformation of PFN1 in vitro and cause accelerated turnover of the PFN1 protein in cells. This mutation-induced destabilization can account for the high propensity of ALS-linked variants to aggregate and also provides rationale for their reported loss-of-function phenotypes in cell-based assays. The source of this destabilization is illuminated by the X-ray crystal structures of several PFN1 proteins, revealing an expanded cavity near the protein core of the …


Interview With Celia Schiffer, Celia Schiffer Jan 2015

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 …


Prototypical Recombinant Multi-Protease Inhibitor Resistant Infectious Molecular Clones Of Human Immunodeficiency Virus Type-1, Vici Varghese, Yumi Mitsuya, W. Jeffrey Fessel, Tommy F. Liu, George Melikian, David Katzenstein, Celia Schiffer, Susan Holmes, Robert Shafer Jan 2015

Prototypical Recombinant Multi-Protease Inhibitor Resistant Infectious Molecular Clones Of Human Immunodeficiency Virus Type-1, Vici Varghese, Yumi Mitsuya, W. Jeffrey Fessel, Tommy F. Liu, George Melikian, David Katzenstein, Celia Schiffer, Susan Holmes, Robert Shafer

Celia A. Schiffer

The many genetic manifestations of HIV-1 protease inhibitor (PI) resistance present challenges to research into the mechanisms of PI-resistance and the assessment of new PIs. To address these challenges, we created a panel of recombinant multi-PI resistant infectious molecular clones designed to represent the spectrum of clinically relevant multi-PI resistant viruses. To assess the representativeness of this panel, we examined the sequences of the panel's viruses in the context of a correlation network of PI-resistance amino acid substitutions in sequences from more than 10,000 patients. The panel of recombinant infectious molecular clones comprised 29 of 41 study-defined PI-resistance amino acid …


Cooperative Effects Of Drug-Resistance Mutations In The Flap Region Of Hiv-1 Protease, Jennifer Foulkes-Murzycki, Christina Rosi, Nese Yilmaz, Robert Shafer, Celia Schiffer Jul 2013

Cooperative Effects Of Drug-Resistance Mutations In The Flap Region Of Hiv-1 Protease, Jennifer Foulkes-Murzycki, Christina Rosi, Nese Yilmaz, Robert Shafer, Celia Schiffer

Celia A. Schiffer

Understanding the interdependence of multiple mutations in conferring drug resistance is crucial to the development of novel and robust inhibitors. As HIV-1 protease continues to adapt and evade inhibitors while still maintaining the ability to specifically recognize and efficiently cleave its substrates, the problem of drug resistance has become more complicated. Under the selective pressure of therapy, correlated mutations accumulate throughout the enzyme to compromise inhibitor binding, but characterizing their energetic interdependency is not straightforward. A particular drug resistant variant (L10I/G48V/I54V/V82A) displays extreme entropy-enthalpy compensation relative to wild-type enzyme but a similar variant (L10I/G48V/I54A/V82A) does not. Individual mutations of sites …


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, …


Exploring The Role Of The Solvent In The Denaturation Of A Protein: A Molecular Dynamics Study Of The Dna Binding Domain Of The 434 Repressor, Celia Schiffer, Volker Dötsch, Kurt Wuthrich, Wilfred Van Gunsteren Nov 2011

Exploring The Role Of The Solvent In The Denaturation Of A Protein: A Molecular Dynamics Study Of The Dna Binding Domain Of The 434 Repressor, Celia Schiffer, Volker Dötsch, Kurt Wuthrich, Wilfred Van Gunsteren

Celia A. Schiffer

Molecular dynamics simulations of the DNA binding domain of 434 repressor are presented which aim at unraveling the role of solvent in protein denaturation. Four altered solvent models, each mimicking various possible aspects of the addition of a denaturant to the aqueous solvent, were used in the simulations to analyze their effects on the stability of the protein. The solvent was altered by selectively changing the Coulombic interaction between water and protein atoms and between different water molecules. The use of a modified solvent model has the advantage of mimicking the presence of denaturant without having denaturant molecules present in …