Backbone Cyclic Peptide, Which Mimics the Nuclear Localization Signal of Human Immunodeficiency Virus Type 1 Matrix Protein, Inhibits Nuclear Import and Virus Production in Nondividing Cells

Abstract

Here, we describe an application of the backbone cyclic (BC) proteinomimetic approach to the design and the synthesis of a BC peptide which functionally mimics the nuclear localization signal (NLS) region of the human immunodeficiency virus type 1 matrix protein (HIV-1 MA). On the basis of the NMR structure of HIV-1 MA, a library of BC peptides was designed and screened for the ability to inhibit nuclear import of NLS−BSA in digitonin-permeabilized HeLa and Colo-205 cultured cells. The screening yielded a lead compound (IC₅₀ = 3 μM) which was used for the design of a second library. This library led to the discovery of a highly potent BC peptide, designated BCvir, with an IC₅₀ value of 35 nM. This inhibitory potency is compared to a value of 12 μM exhibited by the linear parent HIV-1 MA NLS peptide. BCvir also reduced HIV-1 production by 75% in infected nondividing cultured human T-cells and was relatively resistant to tryptic digestion. These properties make BCvir a potential candidate for the development of a novel class of antiviral drugs which will be based on blocking nuclear import of viral genomes.