MUTATIONAL ANALYSIS OF 2 CONSERVED SEQUENCE MOTIFS IN HIV-1 REVERSE-TRANSCRIPTASE

Two conserved sequence motifs, occurring in HIV-1 reverse transcriptase at residues 110-116 and 183-190, have been studied using site-directed mutagenesis of the cloned gene. In particular, aspartates at positions 185 and 186 have each been mutated to either asparagine or glutamate. The resulting mutant proteins were catalytically inactive but still able to bind the template-primer complex, poly rA-oligo dT. Other mutations in these regions resulted in reduced reverse transcriptase activity but the mutation of tyrosine-183 to serine caused a significant increase in the K(m) for dTTP and the K(i) for inhibition by 3'-azidothymidine-triphosphate, 2',3'-dideoxythymidine-triphosphate and phosphonoformic acid.