47 research outputs found
A Molecular Dynamics Simulation of Peptide-Triazole HIV Entry Inhibitor Binding to gp120 Hydrophobic Core
Altered Env conformational dynamics as a mechanism of resistance to peptide‑triazole HIV‑1 inactivators.
Background: We previously developed drug-like peptide triazoles (PTs) that target HIV-1 Envelope (Env) gp120,
potently inhibit viral entry, and irreversibly inactivate virions. Here, we investigated potential mechanisms of viral
escape from this promising class of HIV-1 entry inhibitors.
Results: HIV-1 resistance to cyclic (AAR029b) and linear (KR13) PTs was obtained by dose escalation in viral passaging
experiments. High-level resistance for both inhibitors developed slowly (relative to escape from gp41-targeted
C-peptide inhibitor C37) by acquiring mutations in gp120 both within (Val255) and distant to (Ser143) the putative PT
binding site. The similarity in the resistance profiles for AAR029b and KR13 suggests that the shared IXW pharmacophore
provided the primary pressure for HIV-1 escape. In single-round infectivity studies employing recombinant virus,
V255I/S143N double escape mutants reduced PT antiviral potency by 150- to 3900-fold. Curiously, the combined
mutations had a much smaller impact on PT binding affinity for monomeric gp120 (four to ninefold). This binding
disruption was entirely due to the V255I mutation, which generated few steric clashes with PT in molecular docking.
However, this minor effect on PT affinity belied large, offsetting changes to association enthalpy and entropy. The
escape mutations had negligible effect on CD4 binding and utilization during entry, but significantly altered both
binding thermodynamics and inhibitory potency of the conformationally-specific, anti-CD4i antibody 17b. Moreover,
the escape mutations substantially decreased gp120 shedding induced by either soluble CD4 or AAR029b.
Conclusions: Together, the data suggest that the escape mutations significantly modified the energetic landscape of
Env’s prefusogenic state, altering conformational dynamics to hinder PT-induced irreversible inactivation of Env. This
work therein reveals a unique mode of virus escape for HIV-1, namely, resistance by altering the intrinsic conformational
dynamics of the Env trimerpost-print4093 K
Risk Perceptions Related to SARS and Avian Influenza: Theoretical Foundations of Current Empirical Research
Onset of neurophysin self-association upon neurophysin/neuropeptide hormone precursor biosynthesis
Molecular diagnostics using analytical immuno high performance liquid affinity chromatography
Analytical immuno high performance liquid affinity chromatography (analytical immuno HPLAC) was evaluated as a molecular diagnostic tool. Antibodies raised in rabbits against bovine neurophysin II were immobilized through Protein A crosslinking onto coated silica. Interaction of immobilized antibody with mobile antigen was characterized by zonal and frontal elutions of 14C-labeled bovine neurophysin II under isocratic, nondenaturing conditions. The chromatographic behavior shows that analytical immuno HPLAC with immobilized antibodies can be used to detect the number and functional nature of matrix-interacting antigens in mixtures, thus providing a quantitative chromatographic technology for "antigen mapping.