Insight into the Mechanism of a Peptide Inhibitor of HIV Reverse Transcriptase Dimerization

• Published in: Biochemistry (Easton) 2005-02, Vol.44 (6), p.1909-1918
• Main Authors: Depollier, Julien, Hourdou, Marie-Laure, Aldrian-Herrada, Gudrun, Rothwell, Paul, Restle, Tobias, Divita, Gilles
• Format: Article
• Language: English
• Subjects: Amino Acid Motifs - genetics; Amino Acid Sequence; Anti-HIV Agents - chemistry; Anti-HIV Agents - metabolism; Antiviral Agents - chemical synthesis; Antiviral Agents - genetics; Antiviral Agents - metabolism; Dimerization; Enzyme Stability - genetics; HIV Reverse Transcriptase - antagonists & inhibitors; HIV Reverse Transcriptase - genetics; HIV Reverse Transcriptase - metabolism; Human immunodeficiency virus; Molecular Sequence Data; Mutagenesis, Site-Directed; Oligopeptides - chemical synthesis; Oligopeptides - genetics; Oligopeptides - metabolism; Phenylalanine - genetics; Protein Binding - genetics; Protein Conformation; Protein Interaction Mapping; Protein Structure, Tertiary - genetics; Protein Subunits - antagonists & inhibitors; Protein Subunits - genetics; Protein Subunits - metabolism; Tryptophan - genetics; Viral Proteins - chemistry; Viral Proteins - genetics; Viral Proteins - metabolism
• ISSN: 0006-2960; 1520-4995
• DOI: 10.1021/bi0484264

The biologically active forms of human immunodeficiency viruses type 1 and 2 reverse transcriptase (RT) found in infectious virions are heterodimers. We have previously shown that the dimeric nature of reverse transcriptase represents an important target for the design of a new class of antiviral agents and have designed a short peptide (Pep-7) derived from the tryptophan-rich motif of the connection subdomain that blocks dimerization of reverse transcriptase in vitro and abolishes viral infection. In the present work, we have investigated the mechanism through which this peptide inhibits RT dimerization and consequently viral propagation. We demonstrate that Pep-7 interacts preferentially with the p51 subunit within the heterodimeric reverse transcriptase, which destabilizes reverse transcriptase dimer conformation, thereby triggering dissociation. We have identified two residues Trp24 and Phe61, located on the fingers subdomain of p51, required for Pep-7 binding. Selective mutation of these residues on p51 to a glycine dramatically alters the stability of the RT-heterodimer suggesting that the fingers subdomain of p51 is also involved in stabilization of reverse transcriptase. We propose that the binding site of Pep-7 is located in a cleft between the fingers and the connection subdomains of p51 that contains the two highly conserved residues Phe61 and Trp24.