Evidence of HIV-1 gp120/V3 — CCR5 peptide complex organization in vitro

Abstract The V3-loop of the HIV-1 envelope glycoprotein gp120 interacts with the chemokine receptor CCR5 on the surface of the target cell. Electrostatic interactions between the electropositive V3-loop and the strongly electronegative CCR5 appear to play a prominent role in this process. In the present study we showed by dynamic light scattering that a 3:2 mixture of a linear V3 peptide and CCR5 N-terminal peptide with sulphated tyrosines gave a shift of the relaxation times and the appearance of second peak at longer times, characteristic of complex formation, with dimensions of the order of 1000 nm. The strong interactions between the cationic V3 peptide and the anionic CCR5 N-terminal peptide are manifested in the distinct CW-EPR spectra of the mixture as compared to the separate peptides.