Comparison of Vif Sequences from Diverse Geographical Isolates of HIV Type 1 and SIV cpz Identifies Substitutions Common to Subtype C Isolates and Extensive Variation in a Proposed Nuclear Transport Inhibition Signal

Abstract

We compared the Vif sequences from more than 100 group M and O strains of HIV-1 isolated from diverse geographical regions and various subtypes, in order to identify regions of high variability and those amino acid residues that were highly conserved or invariant. Our analysis found that there were 10 highly conserved domains with additional invariant residues located throughout the protein. Our analysis revealed that in the highly conserved amino-terminal domain, all subtype C isolates examined had a methionine-to-leucine substitution at position 8 and most subtype C isolates had an arginine-to-lysine substitution at position 17 of the protein. Our analysis revealed that the MAP kinase phosphorylation sites, and the cysteine residues at positions 114 and 133, were conserved in Vif sequences from group M, group O, and SIV cpz isolates. Our analysis also shows that the RKKR motif at positions 90-93, proposed as a nuclear transport inhibition signal (NTIS), was conserved neither in different geographical group M and O HIV-1 isolates nor in SIVcpz.