Biochemistry, Biophysics, and Structural Biology Commons^™

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 …

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 …

Synthetic Strategies For Tailoring The Physicochemical And Magnetic Properties Of Hydrophobic Magnetic Ionic Liquids, Omprakash Nacham, Kevin D. Clark, Honglian Yu, Jared L. Anderson

Jared L. Anderson

Magnetic ionic liquids (MILs) are a subclass of ionic liquids (ILs) containing paramagnetic components and are readily manipulated by an external magnetic field. Due to their hydrophilic nature, very few applications of MILs in aqueous systems have been reported. In this study, three general classes of hydrophobic MILs including monocationic, symmetrical/unsymmetrical dicationic, and symmetrical/unsymmetrical tricationic MILs were synthesized and characterized. By tuning the structure of the MIL, various physicochemical properties including water solubility, magnetic susceptibility, and melting point were regulated. MILs synthesized with the benzimidazolium cation were shown to exhibit lower water solubility (0.1% (w/v)) when compared to those containing …

Extraction Of Dna By Magnetic Ionic Liquids: Tunable Solvents For Rapid And Selective Dna Analysis, Kevin D. Clark, Omprakash Nacham, Honglian Yu, Tianhao Li, Melissa M. Yamsek, Donald R. Ronning, Jared L. Anderson

Jared L. Anderson

DNA extraction represents a significant bottleneck in nucleic acid analysis. In this study, hydrophobic magnetic ionic liquids (MILs) were synthesized and employed as solvents for the rapid and efficient extraction of DNA from aqueous solution. The DNA-enriched microdroplets were manipulated by application of a magnetic field. The three MILs examined in this study exhibited unique DNA extraction capabilities when applied toward a variety of DNA samples and matrices. High extraction efficiencies were obtained for smaller single-stranded and double-stranded DNA using the benzyltrioctylammonium bromotrichloroferrate(III) ([(C8)3BnN+][FeCl3Br–]) MIL, while the dicationic 1,12-di(3-hexadecylbenzimidazolium)dodecane bis[(trifluoromethyl)sulfonyl]imide bromotrichloroferrate(III) ([(C16BnIM)2C122+][NTf2–, FeCl3Br–]) MIL produced higher extraction efficiencies for larger …

Repeated Stressors In Adulthood Increase The Rate Of Biological Ageing, Michaela Hau, Mark F. Haussmann, Timothy J. Greives, Christa Matlack, David Costantini, Michael Quetting, James S. Adelman, Ana C. Miranda, Jesko Partecke

James S. Adelman

Individuals of the same age can differ substantially in the degree to which they have accumulated tissue damage, akin to bodily wear and tear, from past experiences. This accumulated tissue damage reflects the individual’s biological age and may better predict physiological and behavioural performance than the individual‘s chronological age. However, at present it remains unclear how to reliably assess biological age in individual wild vertebrates. We exposed hand-raised adult Eurasian blackbirds (Turdus merula) to a combination of repeated immune and disturbance stressors for over one year to determine the effects of chronic stress on potential biomarkers of biological ageing including …

A Novel Antimycobacterial Compound Acts As An Intracellular Iron Chelator., José Argüello, Marte Dragset, Glovanna Poce, Salvatore Alfonso, Teresita Padilla-Benavides, Thomas Loerger, Takushi Kaneko, James Sacchettini, Mariangela Biava, Tanya Parish, Magnus Steigedal, Eric Rubin

José M. Argüello

Efficient iron acquisition is crucial for the pathogenesis of Mycobacterium tuberculosis. Mycobacterial iron uptake and metabolism are therefore attractive targets for antitubercular drug development. Resistance mutations against a novel pyrazolopyrimidinone compound (PZP) that is active against M. tuberculosis have been identified within the gene cluster encoding the ESX-3 type VII secretion system. ESX-3 is required for mycobacterial iron acquisition through the mycobactin siderophore pathway, which could indicate that PZP restricts mycobacterial growth by targeting ESX-3 and thus iron uptake. Surprisingly, we show that ESX-3 is not the cellular target of the compound. We demonstrate that PZP indeed targets iron metabolism; …

The Role Of Histidine Residues In The Specificity Of The Human Zinc Transporter Hzip4, Robert Dempski, Sagar Antala, Elizabeth Bafaro

Robert E. Dempski

ZIP transporters, named after the zinc regulated (Zrt) and iron regulated (Irt) transport proteins, are essential for zinc and iron translocation across cellular membranes. These proteins function to increase the cytosolic concentration of transition metals. While both zinc and iron are essential micronutrients which are required for the structure and/or function of hundreds of cellular proteins, the molecular mechanism of ZIP transporters is not well understood. Complicating mechanistic studies is the observation that the concentration of free zinc and iron is nano to picomolar.

Dysfunctional Conformational Dynamics Of Protein Kinase A Induced By A Lethal Mutant Of Phospholamban Hinder Phosphorylation, Jonggul Kim, Larry R. Masterson, Alessandro Cembran, Raffaello Verardi, Lei Shi, Jiali Gao, Susan S. Taylor, Gianluigi Veglia

Larry Masterson

Peat And Coconut Fiber As Biofilters For Chromium Adsorption From Contaminated Wastewaters, Henryk Koloczek, Jaroslaw Chwastowski, Witold Zukowski

Witold Zukowski

Batch adsorption experiments were performed for the removal of chromium (III) and chromium (VI) ions from aqueous solutions using Canadian peat and coconut fiber. The Langmuir model was used to describe the adsorption isotherm. The maximum adsorption for peat reached 18.75 mg/g for Cr(III) and 8.02 mg/g for Cr(VI), whereas the value for fiber was slightly higher and reached 19.21 mg/g for Cr(III) and 9.54 mg/g for Cr(VI). Both chromium forms could be easily eluted from the materials. The adsorption of chromium forms to organic matter could be explained in terms of formation of donor-acceptor chemical covalent bound with hydroxyl …