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Biochemistry, Biophysics, and Structural Biology Commons

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

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 …


Therapeutic Targeting Of C-Terminal Binding Protein In Human Cancer, Michael W. Straza, Seema Paliwal, Ramesh C. Kovi, Barur R. Rajeshkumar, Peter Trenh, Daniel Parker, Giles F. Whalen, Stephen Lyle, Celia A. Schiffer, Steven R. Grossman Nov 2011

Therapeutic Targeting Of C-Terminal Binding Protein In Human Cancer, Michael W. Straza, Seema Paliwal, Ramesh C. Kovi, Barur R. Rajeshkumar, Peter Trenh, Daniel Parker, Giles F. Whalen, Stephen Lyle, Celia A. Schiffer, Steven R. Grossman

Celia A. Schiffer

The CtBP transcriptional corepressors promote cancer cell survival and migration/invasion. CtBP senses cellular metabolism via a regulatory dehydrogenase domain, and is antagonized by p14/p19(ARF) tumor suppressors. The CtBP dehydrogenase substrate 4-methylthio-2-oxobutyric acid (MTOB) can act as a CtBP inhibitor at high concentrations, and is cytotoxic to cancer cells. MTOB induced apoptosis was p53-independent, correlated with the derepression of the proapoptotic CtBP repression target Bik, and was rescued by CtBP overexpression or Bik silencing. MTOB did not induce apoptosis in mouse embryonic fibroblasts (MEFs), but was increasingly cytotoxic to immortalized and transformed MEFs, suggesting that CtBP inhibition may provide a suitable …


Drug Resistance Against Hcv Ns3/4a Inhibitors Is Defined By The Balance Of Substrate Recognition Versus Inhibitor Binding, Keith P. Romano, Akbar Ali, William E. Royer, Celia A. Schiffer Nov 2011

Drug Resistance Against Hcv Ns3/4a Inhibitors Is Defined By The Balance Of Substrate Recognition Versus Inhibitor Binding, Keith P. Romano, Akbar Ali, William E. Royer, Celia A. Schiffer

Celia A. Schiffer

Hepatitis C virus infects an estimated 180 million people worldwide, prompting enormous efforts to develop inhibitors targeting the essential NS3/4A protease. Resistance against the most promising protease inhibitors, telaprevir, boceprevir, and ITMN-191, has emerged in clinical trials. In this study, crystal structures of the NS3/4A protease domain reveal that viral substrates bind to the protease active site in a conserved manner defining a consensus volume, or substrate envelope. Mutations that confer the most severe resistance in the clinic occur where the inhibitors protrude from the substrate envelope, as these changes selectively weaken inhibitor binding without compromising the binding of substrates. …


Time-Averaging Crystallographic Refinement: Possibilities And Limitations Using Alpha-Cyclodextrin As A Test System, Celia A. Schiffer, P. Gros, Wilfred F. Van Gunsteren Nov 2011

Time-Averaging Crystallographic Refinement: Possibilities And Limitations Using Alpha-Cyclodextrin As A Test System, Celia A. Schiffer, P. Gros, Wilfred F. Van Gunsteren

Celia A. Schiffer

The method of time-averaging crystallographic refinement is assessed using a small molecule, alpha-cyclodextrin, as a test system. A total of 16 refinements are performed on simulated data. Three resolution ranges of the data are used, the memory relaxation time of the averaging is varied, and several overall temperature factors are used. The most critical factor in the reliable application of time-averaging is the resolution of the data. The ratio of data to molecular degrees of freedom should be large enough to avoid overfitting of the data by the time-averaging procedure. The use of a free R-factor can aid in determining …


Resilience To Resistance Of Hiv-1 Protease Inhibitors: Profile Of Darunavir, Eric Lefebvre, Celia A. Schiffer Nov 2011

Resilience To Resistance Of Hiv-1 Protease Inhibitors: Profile Of Darunavir, Eric Lefebvre, Celia A. Schiffer

Celia A. Schiffer

The current effectiveness of HAART in the management of HIV infection is compromised by the emergence of extensively cross-resistant strains of HIV-1, requiring a significant need for new therapeutic agents. Due to its crucial role in viral maturation and therefore HIV-1 replication and infectivity, the HIV-1 protease continues to be a major development target for antiretroviral therapy. However, new protease inhibitors must have higher thresholds to the development of resistance and cross-resistance. Research has demonstrated that the binding characteristics between a protease inhibitor and the active site of the HIV-1 protease are key factors in the development of resistance. More …