Variation trend of the tetrapeptide on the tip of V3 loop of 62 HIV-1 strains isolated in idu of Yunnan from 1990 to 1997

Objective To investigate the variation trend of the amino acid and the corresponding nucleotide sequences of the tetrapeptide on the tip of the V3 loop of HIV-1 strains from intravenous drug users (IDUs) in Yunnan as time goes by. Methods According to the nucleotide sequences of the C2-V3 region of 62 HIV-1 strains isolated from intravenous drug users (IDUs) of Yunnan from 1990 to 1997, the nucleotide sequences of the tetrapeptide on the tip of the V3 loop of HIV-1 envelope protein were analysed. The variation trends with time were discussed. Results The tetrapeptides on the tip of the V3 loop of 62 Yunnan HIV-1 strains showed different amino acid variation with the major one at the fourth amino acid. Moreover, the variation tend to be in a similar pattern. Among the 62 isolated strains, 46 (74.2% ) showed the GPGR tetrapeptide motif, 10 (16.1 %) GPER motif, 4 (6.4%) GPGK motif and 2 (3.3%) GPER motif respectively. The variation at corresponding nucleotide sequence of the tetrapeptide motif was A→G. Conclusion In the period of 1990-1997, the tetrapeptides on the tip of the V3 loop of the HIV-1 strains from infected IDUs people in Yunnan are similar, and the results conform to the GPGR motif pattern of the international B subtype HIV-1SF₂ strain.