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Anderson RF, Shinde SS, Andrau L, Leung B, Skene C, White JM, Lobachevsky PN, Martin RF. Chemical Repair of Radical Damage to the GC Base Pair by DNA-Bound Bisbenzimidazoles. J Phys Chem B 2024. [PMID: 38686959 DOI: 10.1021/acs.jpcb.4c01069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2024]
Abstract
The migration of an electron-loss center (hole) in calf thymus DNA to bisbenzimidazole ligands bound in the minor groove is followed by pulse radiolysis combined with time-resolved spectrophotometry. The initially observed absorption spectrum upon oxidation of DNA by the selenite radical is consistent with spin on cytosine (C), as the GC• pair neutral radical, followed by the spectra of oxidized ligands. The rate of oxidation of bound ligands increased with an increase in the ratio (r) ligands per base pair from 0.005 to 0.04. Both the rate of ligand oxidation and the estimated range of hole transfer (up to 30 DNA base pairs) decrease with the decrease in one-electron reduction potential between the GC• pair neutral radical of ca. 1.54 V and that of the ligand radicals (E0', 0.90-0.99 V). Linear plots of log of the rate of hole transfer versus r give a common intercept at r = 0 and a free energy change of 12.2 ± 0.3 kcal mol-1, ascribed to the GC• pair neutral radical undergoing a structural change, which is in competition to the observed hole transfer along DNA. The rate of hole transfer to the ligands at distance, R, from the GC• pair radical, k2, is described by the relationship k2 = k0 exp(constant/R), where k0 includes the rate constant for surmounting a small barrier.
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Affiliation(s)
- Robert F Anderson
- School of Chemical Sciences, University of Auckland, Private Bag 92019, Victoria Street West, Auckland 1142, New Zealand
- Auckland Cancer Society Research Centre, University of Auckland, Private Bag 92019, Victoria Street West, Auckland 1142, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Private Bag 92019, Victoria Street West, Auckland 1142, New Zealand
| | - Sujata S Shinde
- Auckland Cancer Society Research Centre, University of Auckland, Private Bag 92019, Victoria Street West, Auckland 1142, New Zealand
| | - Laura Andrau
- School of Chemistry and Bio-21 Molecular Science and Biotechnology Institute, University of Melbourne, Melbourne 3052, Australia
| | - Brenda Leung
- School of Chemistry and Bio-21 Molecular Science and Biotechnology Institute, University of Melbourne, Melbourne 3052, Australia
| | - Colin Skene
- School of Chemistry and Bio-21 Molecular Science and Biotechnology Institute, University of Melbourne, Melbourne 3052, Australia
| | - Jonathan M White
- School of Chemistry and Bio-21 Molecular Science and Biotechnology Institute, University of Melbourne, Melbourne 3052, Australia
| | - Pavel N Lobachevsky
- Molecular Radiation Biology, Peter MacCallum Cancer Centre, Melbourne 3052, Australia
| | - Roger F Martin
- School of Chemistry and Bio-21 Molecular Science and Biotechnology Institute, University of Melbourne, Melbourne 3052, Australia
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OGG1 in the Kidney: Beyond Base Excision Repair. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2022; 2022:5774641. [PMID: 36620083 PMCID: PMC9822757 DOI: 10.1155/2022/5774641] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 12/07/2022] [Accepted: 12/08/2022] [Indexed: 01/01/2023]
Abstract
8-Oxoguanine DNA glycosylase (OGG1) is a repair protein for 8-oxoguanine (8-oxoG) in eukaryotic atopic DNA. Through the initial base excision repair (BER) pathway, 8-oxoG is recognized and excised, and subsequently, other proteins are recruited to complete the repair. OGG1 is primarily located in the cytoplasm and can enter the nucleus and mitochondria to repair damaged DNA or to exert epigenetic regulation of gene transcription. OGG1 is involved in a wide range of physiological processes, such as DNA repair, oxidative stress, inflammation, fibrosis, and autophagy. In recent years, studies have found that OGG1 plays an important role in the progression of kidney diseases through repairing DNA, inducing inflammation, regulating autophagy and other transcriptional regulation, and governing protein interactions and functions during disease and injury. In particular, the epigenetic effects of OGG1 in kidney disease have gradually attracted widespread attention. This study reviews the structure and biological functions of OGG1 and the regulatory mechanism of OGG1 in kidney disease. In addition, the possibility of OGG1 as a potential therapeutic target in kidney disease is discussed.
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The Two Faces of the Guanyl Radical: Molecular Context and Behavior. Molecules 2021; 26:molecules26123511. [PMID: 34207639 PMCID: PMC8227002 DOI: 10.3390/molecules26123511] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 05/29/2021] [Accepted: 06/01/2021] [Indexed: 12/16/2022] Open
Abstract
The guanyl radical or neutral guanine radical G(-H)• results from the loss of a hydrogen atom (H•) or an electron/proton (e–/H+) couple from the guanine structures (G). The guanyl radical exists in two tautomeric forms. As the modes of formation of the two tautomers, their relationship and reactivity at the nucleoside level are subjects of intense research and are discussed in a holistic manner, including time-resolved spectroscopies, product studies, and relevant theoretical calculations. Particular attention is given to the one-electron oxidation of the GC pair and the complex mechanism of the deprotonation vs. hydration step of GC•+ pair. The role of the two G(-H)• tautomers in single- and double-stranded oligonucleotides and the G-quadruplex, the supramolecular arrangement that attracts interest for its biological consequences, are considered. The importance of biomarkers of guanine DNA damage is also addressed.
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