Identification of a beta3-peptide HIV fusion inhibitor with improved potency in live cells.

We recently reported a beta(3)-decapeptide, betaWWI-1, that binds a validated gp41 model in vitro and inhibits gp41-mediated fusion in cell culture. Here we report six analogs of betaWWI-1 containing a variety of non-natural side chains in place of the central tryptophan of the WWI-epitope. These analogs were compared on the basis of both gp41 affinity in vitro and fusion inibition in live, HIV-infected cells. One new beta(3)-peptide, betaWXI-a, offers a significantly improved CC(50)/EC(50) ratio in the live cell assay.