Cluster bombardments of 15 keV C(60) on metal-organic interfaces composed of silver atoms and octatetraene molecules were modeled using molecular dynamics computer simulations. Dynamics revealed by the simulations include the formation of holes in the metal overlayers from which underlying organic molecules are sputtered predominantly by a rapid jetlike motion and the implantation of metal atoms and clusters in the underlying organic solid. Both of these processes negatively affect the information depth for cluster bombardment of metal-organic interfaces; therefore, the simulations presented here give a clear picture of the issues associated with depth profiling through metal-organic interfaces.
View Article and Find Full Text PDFA cofactor for HIV-1 (human immunodeficiency virus-type 1) fusion and entry was identified with the use of a novel functional complementary DNA (cDNA) cloning strategy. This protein, designated “fusin,” is a putative G protein–coupled receptor with seven transmembrane segments. Recombinant fusin enabled CD4-expressing nonhuman cell types to support HIV-1 Env-mediated cell fusion and HIV-1 infection.
View Article and Find Full Text PDFJ Magn Reson
February 2009
Competition between nutation (r.f. driven) and adiabatic (rotor-driven) multi-quantum coherence transfer mechanisms in spin 3/2 systems results in diminished performance of rotation induced adiabatic coherence transfer (RIACT) in isotropic multiple-quantum magic-angle spinning (MQMAS) experiments for small e(2)qQ/h (<2 MHz) and high radio-frequency powers.
View Article and Find Full Text PDFHighly active antiretroviral therapy (HAART) against human immunodeficiency virus type 1 (HIV-1) infection dramatically suppresses viral load, leading to marked reductions in HIV-1 associated morbidity and mortality. However, infected cell reservoirs and low-level replication persist in the face of suppressive HAART, leading invariably to viral rebound upon cessation of treatment. Toxins engineered to target the Env glycoprotein on the surface of productively infected cells represent a complementary strategy to deplete these reservoirs.
View Article and Find Full Text PDFHIV-infected cells are selectively killed by an immunotoxin in which a truncated form of Pseudomonas exotoxin A is joined to the variable region of a broadly neutralizing antibody (3B3) that recognizes the viral envelope glycoprotein (Env). To improve the efficacy of this molecule, we used three-dimensional structural information and phage selection data to design 23 single and multiple point mutations in the antibody variable region sequences that contact Env. Substituting an aromatic residue for an aspartate in the third complementarity-determining region of V(H) increased the potency of the immunotoxin by approximately 10-fold in a cell-killing assay.
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