CHARACTERIZATION OF HIV REVERSE TRANSCRIPTASES WITH TYR181-]CYS AND LEU100-]IIE MUTATIONS

Two mutants of human immunodeficiency virus (HIV) reverse transcriptas e (RT), Tyr181 to Cys and Leu100 to Ile, have been prepared and charac terized by use of various inhibitors. As compared to wild type RT the mutant RT's had lower K(cat)/K(m) values. The K(m) values were lower w ith heteropolymeric than with homopolymeric template-primers. Inhibiti on by phosphonoformate was of mixed type with both wild-type and mutan t RT's and the mutants were less sensitive to phosphonoformate than th e wild type RT. The non-nucleoside RT inhibitors 9-Cl-TIBO and L-697,6 61 gave a non-competitive inhibition with respect to substrate of the wild type RT. The mutant RT's were inhibited at higher concentrations, showing a mixed type of inhibition with respect to substrate. ddGTP c aused a competitive inhibition of wild type and mutant RT's with respe ct to substrate. RT preparations with different mutations are useful i n rapidly characterizing the interaction between various inhibitors an d HIV RT and thus facilitate the development of new inhibitors.