Mutational analysis of two conserved sequence motifs in HIV‐1 reverse transcriptase

Abstract

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, aspariates 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 results 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_m for inhibition by 3′‐azi‐Jothymidine‐triphosphate, 2′3′‐dideoxythymidine‐triphosphate and phosphonoformic acid.