Analysis of photohydration of pyrimidines in DNA and RNA

2015 Fiscal Year Final Research Report

• Project/Area Number: 25670064
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Environmental and hygienic pharmacy
• Research Institution: Nihon Pharmaceutical University
• Principal Investigator: Negishi Kazuo 日本薬科大学, 薬学部, 教授 (70116490)
• Co-Investigator(Kenkyū-buntansha): KIMURA MICHIO 日本薬科大学, 薬学部, 准教授 (50349578) ; NEGISHI TOMOE 岡山大学, 医歯薬総合研究科, 准教授 (80116491)
• Project Period (FY): 2013-04-01 – 2016-03-31
• Keywords: UV / TOF-MS / 重水素置換 / DNA / RNA

Outline of Final Research Achievements

It is well known that pyrimidines are readily hydrated upon irradiation by UV. However, its significance in UV toxicity and mutagenicity is still unclear. Among DNA components, cytosines are photohydrated efficiently, while thymine is relatively resistant to the hydration. Because this reaction is reversible and hydrated cytosines are unstable, it is not easy to measure levels of hydration in DNA. We have tried to estimate the hydration by using hydrogen-exchange at 5-position of cytosine. As a model compound, oligonucleotides containing deoxycytidine was employed to study the hydrogen-deuterium exchange. The UV-irradiated sample is dissolved with H2O, and analyzed. We found that the deuterium exchange can be monitored by MALDI-TOF MS as well as NMR measurement. The MS measurement is much easier than NMR, and suitable for multiple analyses. Another aspect is an effect of cellular components on the photohydration. Phosphate can catalyze dehydration from deoxycytidine hydrate.

Free Research Field

分子生物学