Recombinant HIV type 1 gp120 (6535) (a.a. 34-518) [His]

Six potential peptidomimetics of the cross-reactive neutralizing anti-HIV-1 antibody N6 that are able to mimic the pharmacophoric features of this immunoglobulin by specific and effective interactions with the CD4-binding site of the viral gp120 protein were identified by virtual screening and molecular modeling. The key role in the interaction of these compounds with gp120 is shown to play multiple van der Waals contacts with conserved residues of the gp120 Phe(43) cavity critical for the HIV binding to cellular receptor CD4, as well as hydrogen bonds with Asp-368(g)(p120) that increase the chemical affinity without activating unwanted allosteric effect. According to the data of molecular dynamics, the complexes of the identified ligands with gp120 are energetically stable and show the lower values of binding free energy compared with the HIV-1 inhibitors NBD-11021 and DMJ-II-121 used in the calculations as a positive control. The identified compounds may be involved in the design of novel antiviral drugs presenting HIV-1 inhibitors that block the early stages of the development of HIV infection.

The measurement of mRNA transcripts in live cells has been limited by inefficient delivery vehicles for oligonucleotides. Using a delivery platform which utilizes fluorophores capable of forming intramolecular H-type excitonic dimers, we show that antisense oligonucleotides (ASOs) can be delivered across the plasma membrane directly into the cytosol without receptor mediation. With HIV infection of CD4(+)lymphocytes as a model system, we quantitate the level of viral infection present in live single cells with flow cytometry by measuring the hybridization of ASOs to viral sequences; we then compare this measurement with a standard HIV analysis, that is, binding of an antibody against the HIV cell surface protein gp120. The nucleic acids delivery platform described herein also enables inhibition of HIV infection by addition of ASO constructs targeting sequences in the virus' highly conserved 5 '-untranslated region. Our analysis quantitates the level of inhibition by comparing both the MFI values and the mean fluorescence intensity as calculated by integration under each curve. Thus, a means for measuring intracellular transcripts at the live single cell level and the potential for delivery of a new class of antiviral agents is described. (c) 2020 International Society for Advancement of Cytometry