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DNA oxidation by charge transport in mitochondria.
Biochemistry. 2008 Feb 12; 47(6):1511-7.B

Abstract

Sites of oxidative DNA damage in functioning mitochondria have been identified using a rhodium photooxidant as a probe. Here we show that a primer extension reaction can be used to monitor oxidative DNA damage directly in functioning mitochondria after photoreaction with a rhodium intercalator that penetrates the intact mitochondrial membrane. The complex [Rh(phi)2bpy]Cl3 (phi = 9,10-phenanthrenequinonediimine) binds to DNA within the mitochondria and, upon irradiation, initiates DNA oxidation reactions. Significantly, piperidine treatment of the mitochondria leads to protein-dependent primer extension stops spaced every approximately 20 base pairs. Hence, within the mitochondria, the DNA is well covered and packaged by proteins. Photolysis of the mitochondria containing [Rh(phi)2bpy]3+ leads to oxidative DNA damage at positions 260 and 298; both are mutational hot spots associated with cancers. The latter position is the 5'-nucleotide of conserved sequence block II and is critical to replication of the mitochondrial DNA. The oxidative damage is found to be DNA-mediated, utilizing a charge transport mechanism, as the Rh binding sites are spatially separated from the oxidation-prone regions. This long-range DNA-mediated oxidation occurs despite protein association. Indeed, the oxidation of the mitochondrial DNA leads not only to specific oxidative lesions, but also to a corresponding change in the protein-induced stops in the primer extension. Mitochondrial DNA damage promotes specific changes in protein-DNA contacts and is thus sensed by the mitochondrial protein machinery.

Authors+Show Affiliations

Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA.No affiliation info available

Pub Type(s)

Journal Article
Research Support, N.I.H., Extramural

Language

eng

PubMed ID

18189417

Citation

Merino, Edward J., and Jacqueline K. Barton. "DNA Oxidation By Charge Transport in Mitochondria." Biochemistry, vol. 47, no. 6, 2008, pp. 1511-7.
Merino EJ, Barton JK. DNA oxidation by charge transport in mitochondria. Biochemistry. 2008;47(6):1511-7.
Merino, E. J., & Barton, J. K. (2008). DNA oxidation by charge transport in mitochondria. Biochemistry, 47(6), 1511-7. https://doi.org/10.1021/bi701775s
Merino EJ, Barton JK. DNA Oxidation By Charge Transport in Mitochondria. Biochemistry. 2008 Feb 12;47(6):1511-7. PubMed PMID: 18189417.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - DNA oxidation by charge transport in mitochondria. AU - Merino,Edward J, AU - Barton,Jacqueline K, Y1 - 2008/01/12/ PY - 2008/1/15/pubmed PY - 2008/4/2/medline PY - 2008/1/15/entrez SP - 1511 EP - 7 JF - Biochemistry JO - Biochemistry VL - 47 IS - 6 N2 - Sites of oxidative DNA damage in functioning mitochondria have been identified using a rhodium photooxidant as a probe. Here we show that a primer extension reaction can be used to monitor oxidative DNA damage directly in functioning mitochondria after photoreaction with a rhodium intercalator that penetrates the intact mitochondrial membrane. The complex [Rh(phi)2bpy]Cl3 (phi = 9,10-phenanthrenequinonediimine) binds to DNA within the mitochondria and, upon irradiation, initiates DNA oxidation reactions. Significantly, piperidine treatment of the mitochondria leads to protein-dependent primer extension stops spaced every approximately 20 base pairs. Hence, within the mitochondria, the DNA is well covered and packaged by proteins. Photolysis of the mitochondria containing [Rh(phi)2bpy]3+ leads to oxidative DNA damage at positions 260 and 298; both are mutational hot spots associated with cancers. The latter position is the 5'-nucleotide of conserved sequence block II and is critical to replication of the mitochondrial DNA. The oxidative damage is found to be DNA-mediated, utilizing a charge transport mechanism, as the Rh binding sites are spatially separated from the oxidation-prone regions. This long-range DNA-mediated oxidation occurs despite protein association. Indeed, the oxidation of the mitochondrial DNA leads not only to specific oxidative lesions, but also to a corresponding change in the protein-induced stops in the primer extension. Mitochondrial DNA damage promotes specific changes in protein-DNA contacts and is thus sensed by the mitochondrial protein machinery. SN - 0006-2960 UR - https://www.unboundmedicine.com/medline/citation/18189417/DNA_oxidation_by_charge_transport_in_mitochondria_ L2 - https://dx.doi.org/10.1021/bi701775s DB - PRIME DP - Unbound Medicine ER -