A DRUG-RESISTANCE MUTATION IN THE INHIBITOR BINDING POCKET OF HUMAN-IMMUNODEFICIENCY-VIRUS TYPE-1 REVERSE-TRANSCRIPTASE IMPAIRS DNA-SYNTHESIS AND RNA DEGRADATION

Selection of the IIIB strain of human immunodeficiency virus type (HIV -1) resistant to the (alkylamino)piperidine-bis(heteroaryl)piperazine (AAP-BHAP) U-104489 results in substitution of a glycine to glutamate at residue 190 (G190E) of reverse transcriptase (RT). The AAP-BHAP res istant HIV-1 displays reduced in vitro replication capacity [Olmsted, R. A., et al. (1966) J. Virol. 70, 3698-3705]. We report here that the G190E mutation in recombinant heterodimeric HIV-1 RT, compared to the wildtype RT (G190) or a G190A control mutant, results in a 40% and 80 % reduction in the polymerase and RNase H specific enzymatic activitie s, respectively. A primer-extension assay that allowed determination o f DNA elongation by the G190E mutant RT on a heteropolymeric HIV-1 gag -based RNA template showed an overall decrease in DNA polymerization. The size distribution of products generated by G190E RT-associated RNa se H digestion of RNA from [S-35]poly(rA). poly(dT) was markedly disti nct from that of the G190A RT and was consistent with the observed red uction in RT-associated RNase H activity of the G190E RT. When challen ged with unlabeled substrates, the G190E RT was relatively nonprocessi ve with respect to DNA synthesis and RNA degradation. It is concluded that the deleterious effect of the G190E resistance mutation on both o f these RT functions is most likely involved in the observed retarded replication capacity of the AAP-BHAP-(U-104489-) resistant HIV-1.