Allosteric mechanism of an oximino-piperidino-piperidine antagonist for the CCR5 chemokine receptor

The first step for the HIV-1 virus infecting host cell is bound with the CCR5 chemokine receptor. A set of allosteric inhibitors of oximino-piperidino-piperidine antagonists for CCR5 chemokine receptor was discovered. However, the allosteric mechanism of these inhibitors is still unsolved. Therefore, residue-level dynamics correlation network combining with on molecular dynamics simulation was used to investigate the allosteric mechanism. The dynamics correlation network of bound CCR5 is significantly different from that of free CCR5. The community of the most active complex suggests that the allosteric information can freely transfer from the allosteric site to the effector site of the second extracellular loop, while the information transfers bottleneck for the less active one. Here, a hypothesis was proposed that "binding-induced allosteric mechanism" was used to reveal the allosteric regulation of antagonists and the network perturbation confirmed it. Finally, the shortest path algorithm was used to identify the possible allosteric pathway with Gly173-Lys171-Thr177-Tyr89-LIG which was evaluated by the network perturbation of key residue. Furthermore, the efficiency of allostery for the most active system is the highest among these antagonist complexes. The strategy targeting the allosteric pathway can be used to design novel inhibitors of HIV-1 virus.

How to assess the binding strength of antibodies elicited by vaccination against HIV and other viruses

Vaccines that protect against viral infections generally induce neutralizing antibodies. When vaccines are evaluated, the need arises to assess the affinity maturation of the antibody responses. Binding titers of polyclonal sera depend not only on the affinities of the constituent antibodies but also on their individual concentrations, which are difficult to ascertain. Therefore an assay based on chaotrope disruption of antibody-antigen complexes was designed for measuring binding strength. This assay works well with many viral antigens but gives differential results depending on the conformational dependence of epitopes on complex antigens such as the envelope glycoprotein of HIV-1. Kinetic binding assays might offer alternatives, since they can measure average off-rate constants for polyclonal antibodies in a serum. Here, potentials and fallacies of these techniques are discussed.

2-Aminothiazolones as anti-HIV agents that act as gp120-CD4 inhibitors

We report here the synthesis of 2-aminothiazolones along with their biological properties as novel anti-HIV agents. Such compounds have proven to act through the inhibition of the gp120-CD4 protein-protein interaction that occurs at the very early stage of the HIV-1 entry process. No cytotoxicity was found for these compounds, and broad antiviral activities against laboratory strains and pseudotyped viruses were documented. Docking simulations have also been applied to predict the mechanism, at the molecular level, by which the inhibitors were able to interact within the Phe43 cavity of HIV-1 gp120. Furthermore, a preliminary absorption, distribution, metabolism, and excretion (ADME) evaluation was performed. Overall, this study led the basis for the development of more potent HIV entry inhibitors.