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Full-Text Articles in Medicinal-Pharmaceutical Chemistry

Synthesis And Flammability Testing Of Epoxy Functionalized Phosphorous-Based Flame Retardants, Vladimir Benin, Xuemei Cui, Alexander Morgan, Karl Seiwert Nov 2015

Synthesis And Flammability Testing Of Epoxy Functionalized Phosphorous-Based Flame Retardants, Vladimir Benin, Xuemei Cui, Alexander Morgan, Karl Seiwert

Vladimir Benin

Several potential new phosphorus-containing flame retardant molecules were evaluated for heat release reduction potential by incorporation of the molecules into a polyurethane, generated from methylene diphenyl diisocyanate and 1,3-propane diol. The heat release reduction potential of these substances was evaluated using the pyrolysis combustion flow calorimeter (PCFC). The polyurethanes were prepared in the presence of the potential flame retardants via solvent mixing and copolymerization methods to qualitatively evaluate their potential reactivity into the polyurethane prior to heat release testing. The functionality of the flame retardants was epoxide based that would potentially react with the diol during polyurethane synthesis. Flammability ...


Synthesis, Structural Studies And Desilylation Reactions Of Some N-2-(Trimethylsilyl)Ethyl-N-Nitrosocarbamates, Arpitha Thakkalapally, Vladimir Benin Nov 2015

Synthesis, Structural Studies And Desilylation Reactions Of Some N-2-(Trimethylsilyl)Ethyl-N-Nitrosocarbamates, Arpitha Thakkalapally, Vladimir Benin

Vladimir Benin

The present report describes the preparation and characterization of several N-2-(trimethylsilyl)ethyl-N-nitrosocarbamates, designed as precursors to thermally unstable secondary N-nitrosocarbamate anions via fluoride-assisted cleavage. X-ray structural studies demonstrate that the core N-nitrosocarbamate moiety has a nearly planar geometry, with an s-E orientation at the N–N bond. DFT calculations (B3LYP/6-31+G(d)) reproduce accurately the structural features of the title compounds and detailed conformational analysis at the same level of theory addresses the long-standing issue of preferred geometries for three classes of related structures: N-nitrosocarbamates, N-nitrosoureas and N-nitrosoamides. Desilylation ...


New Technologies For Glycomic Analysis: Toward A Systematic Understanding Of The Glycome, John Rakus, Lara Mahal Jul 2015

New Technologies For Glycomic Analysis: Toward A Systematic Understanding Of The Glycome, John Rakus, Lara Mahal

John F. Rakus

Carbohydrates are the most difficult class of biological molecules to study by high-throughput methods owing to the chemical similarities between the constituent monosaccharide building blocks, template-less biosynthesis, and the lack of clearly identifiable consensus sequences for the glycan modification of cohorts of glycoproteins. These molecules are crucial for a wide variety of cellular processes ranging from cell-cell communication to immunity, and they are altered in disease states such as cancer and inflammation. Thus, there has been a dedicated effort to develop glycan analysis into a high-throughput analytical field termed glycomics. Herein we highlight major advances in applying separation, mass spectrometry ...


Mir-30b/30d Regulation Of Galnac Transferases Enhances Invasion And Immunosuppression During Metastasis, Avital Gaziel-Sovran, Miguel Segura, Raffaella Di Micco, Mary Collins, Douglas Hanniford, Eleazar De Miera, John Rakus, John Dankert, Shulian Shang, Robert Kerbel, Nina Bhardwaj, Yongzhao Shao, Farbod Darvishian, Jiri Zavadil, Adrian Erlebacher, Lara Mahal, Iman Osman, Eva Hernando Jul 2015

Mir-30b/30d Regulation Of Galnac Transferases Enhances Invasion And Immunosuppression During Metastasis, Avital Gaziel-Sovran, Miguel Segura, Raffaella Di Micco, Mary Collins, Douglas Hanniford, Eleazar De Miera, John Rakus, John Dankert, Shulian Shang, Robert Kerbel, Nina Bhardwaj, Yongzhao Shao, Farbod Darvishian, Jiri Zavadil, Adrian Erlebacher, Lara Mahal, Iman Osman, Eva Hernando

John F. Rakus

To metastasize, a tumor cell must acquire abilities such as the capacity to colonize new tissue and evade immune surveillance. Recent evidence suggests that microRNAs can promote the evolution of malignant behaviors by regulating multiple targets. We performed a microRNA analysis of human melanoma, a highly invasive cancer, and found that miR-30b/30d upregulation correlates with stage, metastatic potential, shorter time to recurrence, and reduced overall survival. Ectopic expression of miR-30b/30d promoted the metastatic behavior of melanoma cells by directly targeting the GalNAc transferase GALNT7, resulted in increased synthesis of the immunosuppressive cytokine IL-10, and reduced immune cell activation ...


Structure-Guided Design Of A High Affinity Inhibitor To Human Ctbp, Brendan Hilbert, Benjamin Morris, Keith Ellis, Janet Paulsen, Celia Schiffer, Steven Grossman, William Royer May 2015

Structure-Guided Design Of A High Affinity Inhibitor To Human Ctbp, Brendan Hilbert, Benjamin Morris, Keith Ellis, Janet Paulsen, Celia Schiffer, Steven Grossman, William Royer

Celia A. Schiffer

Oncogenic transcriptional coregulators C-terminal Binding Protein (CtBP) 1 and 2 possess regulatory d-isomer specific 2-hydroxyacid dehydrogenase (D2-HDH) domains that provide an attractive target for small molecule intervention. Findings that the CtBP substrate 4-methylthio 2-oxobutyric acid (MTOB) can interfere with CtBP oncogenic activity in cell culture and in mice confirm that such inhibitors could have therapeutic benefit. Recent crystal structures of CtBP 1 and 2 revealed that MTOB binds in an active site containing a dominant tryptophan and a hydrophilic cavity, neither of which are present in other D2-HDH family members. Here, we demonstrate the effectiveness of exploiting these active site ...


Improving The Resistance Profile Of Hepatitis C Ns3/4a Inhibitors: Dynamic Substrate Envelope Guided Design, Aysegul Ozen, Woody Sherman, Celia Schiffer Jan 2015

Improving The Resistance Profile Of Hepatitis C Ns3/4a Inhibitors: Dynamic Substrate Envelope Guided Design, Aysegul Ozen, Woody Sherman, Celia Schiffer

Celia A. Schiffer

Drug resistance is a principal concern in the treatment of quickly evolving diseases. The viral protease NS3/4A is a primary drug target for the hepatitis C virus (HCV) and is known to evolve resistance mutations in response to drug therapy. At the molecular level, drug resistance reflects a subtle change in the balance of molecular recognition by NS3/4A; the drug resistant protease variants are no longer effectively inhibited by the competitive active site inhibitors but can still process the natural substrates with enough efficiency for viral survival. In previous works we have developed the "substrate envelope" hypothesis, which ...


Development Of A Novel Screening Strategy Designed To Discover A New Class Of Hiv Drugs, Nancy Cheng, Sook-Kyung Lee, P. Donover, Mel Reichman, Celia Schiffer, Emily Hull-Ryde, Ronald Swanstrom, William Janzen Jan 2015

Development Of A Novel Screening Strategy Designed To Discover A New Class Of Hiv Drugs, Nancy Cheng, Sook-Kyung Lee, P. Donover, Mel Reichman, Celia Schiffer, Emily Hull-Ryde, Ronald Swanstrom, William Janzen

Celia A. Schiffer

Current antiretroviral treatments target multiple pathways important for human immunodeficiency virus (HIV) multiplication, including viral entry, synthesis and integration of the DNA provirus, and the processing of viral polyprotein precursors. However, HIV is becoming increasingly resistant to these "combination therapies." Recent findings show that inhibition of HIV Gag protein cleavage into its two structural proteins, matrix (MA) and capsid (CA), has a devastating effect on viral production, revealing a potential new target class for HIV treatment. Unlike the widely used HIV protease inhibitors, this new class of inhibitor would target the substrate, not the protease enzyme itself. This approach offers ...


Crystal Structures Of Human Ctbp In Complex With Substrate Mtob Reveal Active Site Features Useful For Inhibitor Design, Brendan Hilbert, Steven Grossman, Celia Schiffer, William Royer Jan 2015

Crystal Structures Of Human Ctbp In Complex With Substrate Mtob Reveal Active Site Features Useful For Inhibitor Design, Brendan Hilbert, Steven Grossman, Celia Schiffer, William Royer

Celia A. Schiffer

The oncogenic corepressors C-terminal Binding Protein (CtBP) 1 and 2 harbor regulatory d-isomer specific 2-hydroxyacid dehydrogenase (d2-HDH) domains. 4-Methylthio 2-oxobutyric acid (MTOB) exhibits substrate inhibition and can interfere with CtBP oncogenic activity in cell culture and mice. Crystal structures of human CtBP1 and CtBP2 in complex with MTOB and NAD(+) revealed two key features: a conserved tryptophan that likely contributes to substrate specificity and a hydrophilic cavity that links MTOB with an NAD(+) phosphate. Neither feature is present in other d2-HDH enzymes. These structures thus offer key opportunities for the development of highly selective anti-neoplastic CtBP inhibitors. Elsevier B.V ...


The Synthesis And Biological Evaluation Of Tamandarin B Analogs, Kenneth Lassen Feb 2012

The Synthesis And Biological Evaluation Of Tamandarin B Analogs, Kenneth Lassen

Kenneth Lassen

The tamandarin and didemnins are a class of cyclodepsipeptides that have shown a wide range of biological activity. The didemnins have demonstrated antitumor, antiviral and immunosuppressive activity at low nano- and femtomolar levels. Didemnin B was the first marine natural product to enter clinical trials in humans in the United States. The structures of tamandarins A and B were reported in 2000 and possess almost identical structure and biological activity to didemnin B. These compounds have shown impressive biological activity and some progress has been made in establishing structure-activity relationships. However, their molecular mechanism of action is still unclear. The ...


Promise Of Advances In Simulation Methods For Protein Crystallography: Implicit Solvent Models, Time-Averaging Refinement, And Quantum Mechanical Modeling, Celia Schiffer, Jan Hermans Nov 2011

Promise Of Advances In Simulation Methods For Protein Crystallography: Implicit Solvent Models, Time-Averaging Refinement, And Quantum Mechanical Modeling, Celia Schiffer, Jan Hermans

Celia A. Schiffer

No abstract provided.


Competition Between Ski And Creb-Binding Protein For Binding To Smad Proteins In Transforming Growth Factor-Beta Signaling, Weijun Chen, Suvana Lam, Hema Srinath, Celia Schiffer, William Royer, Kai Lin Nov 2011

Competition Between Ski And Creb-Binding Protein For Binding To Smad Proteins In Transforming Growth Factor-Beta Signaling, Weijun Chen, Suvana Lam, Hema Srinath, Celia Schiffer, William Royer, Kai Lin

Celia A. Schiffer

The family of Smad proteins mediates transforming growth factor-beta (TGF-beta) signaling in cell growth and differentiation. Smads repress or activate TGF-beta signaling by interacting with corepressors (e.g. Ski) or coactivators (e.g. CREB-binding protein (CBP)), respectively. Specifically, Ski has been shown to interfere with the interaction between Smad3 and CBP. However, it is unclear whether Ski competes with CBP for binding to Smads and whether they can interact with Smad3 at the same binding surface on Smad3. We investigated the interactions among purified constructs of Smad, Ski, and CBP in vitro by size-exclusion chromatography, isothermal titration calorimetry, and mutational ...


Mass Spectrometry Analysis Of Hiv-1 Vif Reveals An Increase In Ordered Structure Upon Oligomerization In Regions Necessary For Viral Infectivity, Jared Auclair, Karin Green, Shivender Shandilya, James Evans, Mohan Somasundaran, Celia Schiffer Nov 2011

Mass Spectrometry Analysis Of Hiv-1 Vif Reveals An Increase In Ordered Structure Upon Oligomerization In Regions Necessary For Viral Infectivity, Jared Auclair, Karin Green, Shivender Shandilya, James Evans, Mohan Somasundaran, Celia Schiffer

Celia A. Schiffer

HIV-1 Vif, an accessory protein in the viral genome, performs an important role in viral pathogenesis by facilitating the degradation of APOBEC3G, an endogenous cellular inhibitor of HIV-1 replication. In this study, intrinsically disordered regions are predicted in HIV-1 Vif using sequence-based algorithms. Intrinsic disorder may explain why traditional structure determination of HIV-1 Vif has been elusive, making structure-based drug design impossible. To characterize HIV-1 Vif's structural topology and to map the domains involved in oligomerization we used chemical cross-linking, proteolysis, and mass spectrometry. Cross-linking showed evidence of monomer, dimer, and trimer species via denaturing gel analysis and an ...


Viral Protease Inhibitors, Jeffrey Anderson, Celia Schiffer, Sook-Kyung Lee, Ronald Swanstrom Nov 2011

Viral Protease Inhibitors, Jeffrey Anderson, Celia Schiffer, Sook-Kyung Lee, Ronald Swanstrom

Celia A. Schiffer

This review provides an overview of the development of viral protease inhibitors as antiviral drugs. We concentrate on HIV-1 protease inhibitors, as these have made the most significant advances in the recent past. Thus, we discuss the biochemistry of HIV-1 protease, inhibitor development, clinical use of inhibitors, and evolution of resistance. Since many different viruses encode essential proteases, it is possible to envision the development of a potent protease inhibitor for other viruses if the processing site sequence and the catalytic mechanism are known. At this time, interest in developing inhibitors is limited to viruses that cause chronic disease, viruses ...


Mutation Patterns And Structural Correlates In Human Immunodeficiency Virus Type 1 Protease Following Different Protease Inhibitor Treatments, Thomas Wu, Celia Schiffer, Matthew Gonzales, Jonathan Taylor, Rami Kantor, Sunwen Chou, Dennis Israelski, Andrew Zolopa, W. Jeffrey Fessel, Robert Shafer Nov 2011

Mutation Patterns And Structural Correlates In Human Immunodeficiency Virus Type 1 Protease Following Different Protease Inhibitor Treatments, Thomas Wu, Celia Schiffer, Matthew Gonzales, Jonathan Taylor, Rami Kantor, Sunwen Chou, Dennis Israelski, Andrew Zolopa, W. Jeffrey Fessel, Robert Shafer

Celia A. Schiffer

Although many human immunodeficiency virus type 1 (HIV-1)-infected persons are treated with multiple protease inhibitors in combination or in succession, mutation patterns of protease isolates from these persons have not been characterized. We collected and analyzed 2,244 subtype B HIV-1 isolates from 1,919 persons with different protease inhibitor experiences: 1,004 isolates from untreated persons, 637 isolates from persons who received one protease inhibitor, and 603 isolates from persons receiving two or more protease inhibitors. The median number of protease mutations per isolate increased from 4 in untreated persons to 12 in persons who had received four ...


Curling Of Flap Tips In Hiv-1 Protease As A Mechanism For Substrate Entry And Tolerance Of Drug Resistance, Walter Scott, Celia Schiffer Nov 2011

Curling Of Flap Tips In Hiv-1 Protease As A Mechanism For Substrate Entry And Tolerance Of Drug Resistance, Walter Scott, Celia Schiffer

Celia A. Schiffer

BACKGROUND: The human immunodeficiency virus type 1 (HIV-1) protease is an essential viral protein that is a major drug target in the fight against Acquired Immune Deficiency Syndrome (AIDS). Access to the active site of this homodimeric enzyme is gained when two large flaps, one from each monomer, open. The flap movements are therefore central to the function of the enzyme, yet determining how these flaps move at an atomic level has not been experimentally possible.

RESULTS: In the present study, we observe the flaps of HIV-1 protease completely opening during a 10 ns solvated molecular dynamics simulation starting from ...


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 ...


Structural Analysis Of Human Immunodeficiency Virus Type 1 Crf01_Ae Protease In Complex With The Substrate P1-P6., Rajintha Bandaranayake, Moses Prabu-Jeyabalan, Junko Kakizawa, Wataru Sugiura, Celia Schiffer Nov 2011

Structural Analysis Of Human Immunodeficiency Virus Type 1 Crf01_Ae Protease In Complex With The Substrate P1-P6., Rajintha Bandaranayake, Moses Prabu-Jeyabalan, Junko Kakizawa, Wataru Sugiura, Celia Schiffer

Celia A. Schiffer

The effect of amino acid variability between human immunodeficiency virus type 1 (HIV-1) clades on structure and the emergence of resistance mutations in HIV-1 protease has become an area of significant interest in recent years. We determined the first crystal structure of the HIV-1 CRF01_AE protease in complex with the p1-p6 substrate to a resolution of 2.8 A. Hydrogen bonding between the flap hinge and the protease core regions shows significant structural rearrangements in CRF01_AE protease compared to the clade B protease structure.


Investigation Of Protein Unfolding And Stability By Computer Simulation, Wilfred Van Gunsteren, P. Hunenberger, H. Kovacs, A. Mark, Celia Schiffer Nov 2011

Investigation Of Protein Unfolding And Stability By Computer Simulation, Wilfred Van Gunsteren, P. Hunenberger, H. Kovacs, A. Mark, Celia Schiffer

Celia A. Schiffer

Structural, dynamic and energetic properties of proteins in solution can be studied in atomic detail by molecular dynamics computer simulation. Protein unfolding can be caused by a variety of driving forces induced in different ways: increased temperature or pressure, change of solvent composition, or protein amino acid mutation. The stability and unfolding of four different proteins (bovine pancreatic trypsin inhibitor, hen egg white lysozyme, the surfactant protein C and the DNA-binding domain of the 434 repressor) have been studied by applying the afore-mentioned driving forces and also to some artificial forces. The results give a picture of protein (in)stability ...