R964C mutation of DNA polymerase gamma imparts increased stavudine toxicity by decreasing nucleoside analog discrimination and impairing polymerase activity.
The R964C mutation of human DNA polymerase gamma was recently linked to stavudine (d4T)-mediated mitochondrial toxicity. We utilized pre-steady-state kinetics to determine the effect of this mutation on incorporation of natural substrate dTTP and the active metabolite of d4T (d4TTP). The R964C polymerase gamma holoenzyme demonstrated a 33% decrease in dTTP incorporation efficiency and a threefold-lower d4TTP discrimination relative to that of the wild-type polymerase gamma, providing a mechanistic basis for genetic predisposition to nucleoside reverse transcriptase inhibitor toxicity.
Bailey
Christopher M
CM
Department of Pharmacology, Yale University School of Medicine, 333 Cedar St., New Haven, CT 06520, USA.
Kasiviswanathan
Rajesh
R
Copeland
William C
WC
Anderson
Karen S
KS
D019380:Anti-HIV Agents / Q000633:toxicity*; D000074002:DNA Polymerase gamma; D004259:DNA-Directed DNA Polymerase / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D008928:Mitochondria / Q000187:drug effects*; D009154:Mutation; D018119:Stavudine / Q000633:toxicity*; D013942:Thymine Nucleotides
D019380:Anti-HIV Agents; D013942:Thymine Nucleotides; D018119:Stavudine; D000074002:DNA Polymerase gamma; D004259:DNA-Directed DNA Polymerase; C024157:thymidine 5'-triphosphate