Vif is an auxiliary factor of the HIV-1 reverse transcriptase and facilitates abasic site bypass

• Published in: Biochemical journal 2004-11, Vol.383 (Pt. 3), p.475-482
• Main Authors: Cancio, Reynel, Spadari, Silvio, Maga, Giovanni
• Format: Article
• Language: English
• Subjects: DNA Primers - metabolism; DNA, Viral - metabolism; DNA-Directed RNA Polymerases - metabolism; Gene Products, vif - physiology; HIV Reverse Transcriptase - metabolism; HIV-1 - enzymology; HIV-1 - genetics; Human immunodeficiency virus 1; Kinetics; Nucleic Acids - metabolism; Peptides - physiology; Protein Binding - physiology; Protein Structure, Tertiary; Purines - metabolism; Pyrimidines - metabolism; Recombinant Proteins - metabolism; Retroviridae Proteins - physiology; RNA, Viral - metabolism; RNA-Directed DNA Polymerase - metabolism; Substrate Specificity; Templates, Genetic; Thermodynamics; vif Gene Products, Human Immunodeficiency Virus
• ISSN: 0264-6021; 1470-8728
• DOI: 10.1042/BJ20040914

The HIV-1 accessory protein Vif was found to modulate the RNA- and DNA-dependent DNA synthesis activity of the viral RT (reverse transcriptase) in two ways: (i) it stimulated the binding of the viral RT to the primer by increasing the association rate kcat/K(m) and by decreasing the thermodynamic barrier DeltaH([ES]) for complex formation, and (ii) it increased the polymerization rate of HIV-1 RT. A Vif mutant lacking the final 56 amino acids at the C-terminus failed to stimulate the viral RT. On the other hand, another Vif mutant lacking the first 43 amino acids at the N-terminus, which are involved in RNA binding and interaction with the viral protease, was able to stimulate RT activity. In addition, Vif was found to promote the bypass of an abasic site by HIV-1 RT.