Title
An Analysis of Enzyme Kinetics Data for Mitochondrial DNA Strand Termination by Nucleoside Reverse Transcription Inhibitors.
Abstract
Nucleoside analogs used in antiretroviral treatment have been associated with mitochondrial toxicity. The polymerase-gamma hypothesis states that this toxicity stems from the analogs' inhibition of the mitochondrial DNA polymerase (polymerase-gamma) leading to mitochondrial DNA (mtDNA) depletion. We have constructed a computational model of the interaction of polymerase-gamma with activated nucleoside and nucleotide analog drugs, based on experimentally measured reaction rates and base excision rates, together with the mtDNA genome size, the human mtDNA sequence, and mitochondrial dNTP concentrations. The model predicts an approximately 1000-fold difference in the activated drug concentration required for a 50% probability of mtDNA strand termination between the activated di-deoxy analogs d4T, ddC, and ddI (activated to ddA) and the activated forms of the analogs 3TC, TDF, AZT, FTC, and ABC. These predictions are supported by experimental and clinical data showing significantly greater mtDNA depletion in cell culture and patient samples caused by the di-deoxy analog drugs. For zidovudine (AZT) we calculated a very low mtDNA replication termination probability, in contrast to its reported mitochondrial toxicity in vitro and clinically. Therefore AZT mitochondrial toxicity is likely due to a mechanism that does not involve strand termination of mtDNA replication.
Year
DOI
Venue
2009
10.1371/journal.pcbi.1000261
PLOS COMPUTATIONAL BIOLOGY
Keywords
Field
DocType
mitochondrial dna,enzyme kinetics,computer model,nucleotides,dna replication,reaction rate,reverse transcription,genome size,kinetics,cell culture
Zidovudine,Biology,Reverse transcriptase,Mitochondrion,Nucleoside,Mitochondrial DNA,Polymerase,DNA replication,Genetics,Molecular biology,Mitochondrial toxicity
Journal
Volume
Issue
ISSN
5
1
1553-734X
Citations 
PageRank 
References 
1
0.63
0
Authors
4
Name
Order
Citations
PageRank
Katherine V. Wendelsdorf110.63
Zhuo Song232.10
Yang Cao3519.23
David C. Samuels4186.68