Cited by 156Mitochondrial Function and PathologyDNA Repair MechanismsEnzyme Structure and Function

Active Site Mutation in DNA Polymerase γ Associated with Progressive External Ophthalmoplegia Causes Error-prone DNA Synthesis

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Ponamarev, Mikhail V., Longley, Matthew J., Nguyen, Dinh, Kunkel, Thomas A., Copeland, William C.·2002·Journal of Biological Chemistry

Abstract

Progressive external ophthalmoplegia (PEO) is a heritable mitochondrial disorder characterized by the accumulation of multiple point mutations and large deletions in mtDNA. Autosomal dominant PEO was recently shown to co-segregate with a heterozygous Y955C mutation in the human gene encoding the sole mitochondrial DNA polymerase, DNA polymerase gamma (pol gamma). Since Tyr-955 is a highly conserved residue critical for nucleotide recognition among family A DNA polymerases, we analyzed the effects of the Y955C mutation on the kinetics and fidelity of DNA synthesis by the purified human mutant polymerase in complex with its accessory subunit. The Y955C enzyme retains a wild-type catalytic rate (k(cat)) but suffers a 45-fold decrease in apparent binding affinity for the incoming nucleoside triphosphate (K(m)). The Y955C derivative is 2-fold less accurate for base pair substitutions than wild-type pol gamma despite the action of intrinsic exonucleolytic proofreading. The full mutator effect of the Y955C substitution was revealed by genetic inactivation of the exonuclease, and error rates for certain mismatches were elevated by 10-100-fold. The error-prone DNA synthesis observed for the Y955C pol gamma is consistent with the accumulation of mtDNA mutations in patients with PEO.

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  1. Esposito, L. A., Melov, S., Panov, A., Cottrell, B. A., and Wallace, D. C. (1999) Proc. Natl. Acad. Sci. U. S. A. 96, 4820 -4825
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Authors
Ponamarev, M. V., Longley, M. J., Nguyen, D., Kunkel, T. A., & Copeland, W. C.
Affiliations
National Institutes of Health (US)
Corresponding author
Copeland, William C.
Venue
Journal of Biological Chemistry
Publisher
Elsevier BV
Published
2002-05
Volume
277
Issue
18
Pages
15225-15228
ISSN
0021-9258 (ISSN-L)
OpenAlex
W2038833748
Cited by
156
References
29
Citations by year
2025: 5 · 2024: 3 · 2023: 4 · 2022: 2 · 2021: 1 · 2019: 2 · 2018: 2 · 2017: 3 · 2016: 2 · 2015: 1 · 2014: 6 · 2013: 5 · 2012: 5
FWCI
7.76
Type
journal article
Language
en
Open access
Locations
  • Journal of Biological Chemistry (publishedVersion, cc-by)
  • PubMed (publishedVersion)
Topics
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Mitochondrial Function and Pathology
  • Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › DNA Repair Mechanisms
  • Physical Sciences › Materials Science › Materials Chemistry › Enzyme Structure and Function
Keywords
chronic progressive external ophthalmoplegia, DNA polymerase gamma, mitochondrial DNA, proofreading exonuclease, nucleotide binding affinity, mitochondrial DNA mutations, mitochondrial disease, polymerase fidelity
MeSH terms
DNA Polymerase gamma, Amino Acid Sequence, Base Sequence, Binding Sites, DNA-Directed DNA Polymerase, DNA Replication, DNA, Mitochondrial, Genes, Dominant, Humans, Mitochondria, Models, Molecular, Molecular Sequence Data, Mutation, Protein Conformation, Tyrosine, Conserved Sequence, Ophthalmoplegia, Chronic Progressive External, Amino Acid Substitution

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