Role of induced fit in limiting discrimination against AZT by HIV reverse transcriptase.

ABSTRACT: Single turnover kinetic studies were conducted using fluorescently labeled HIV reverse transcriptase (RT) to evaluate the role of nucleotide-induced changes in enzyme structure in the selectivity against AZT in order to explore why AZT-resistant forms of the enzyme fail to significantly discriminate against AZT. Fluorescent labeling of HIV RT provided a signal to monitor the isomerization from "open" to "closed" states following nucleotide binding. We measured the rate constants governing nucleotide binding and enzyme isomerization for TTP and AZT-triphosphate by the wild-type and AZT-resistant forms of the enzyme containing the thymidine analogue mutations (TAMs). We show that the TAMs alter the kinetics of AZT incorporation by weakening ground-state nucleotide binding and decreasing the

SUBMITTER: Kellinger MW 

PROVIDER: S-EPMC3381507 | biostudies-literature | 2011 Jun

REPOSITORIES: biostudies-literature