Proton Transfer of Guanine Radical Cations Studied by Time-Resolved Resonance Raman Spectroscopy Combined with Pulse Radiolysis

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• 作者：Jungkweon Choi ; Cheolhee Yang ; Mamoru Fujitsuka ; Sachiko Tojo ; Hyocherl Ihee ; Tetsuro Majima
• 刊名：The Journal of Physical Chemistry Letters
• 出版年：2015
• 出版时间：December 17, 2015
• 年：2015
• 卷：6
• 期：24
• 页码：5045-5050
• 全文大小：407K
• ISSN：1948-7185

文摘

The oxidation of guanine (G) is studied by using transient absorption and time-resolved resonance Raman spectroscopies combined with pulse radiolysis. The transient absorption spectral change demonstrates that the neutral radical of G (G^{鈥?/sup>(鈭扝+)), generated by the deprotonation of G radical cation (G鈥?), is rapidly converted to other G radical species. The formation of this species shows the pH dependence, suggesting that it is the G radical cation (G鈥?)鈥?formed from the protonation at the N7 of G鈥?/sup>(鈭扝+). On one hand, most Raman bands of (G鈥?)鈥?are up-shifted relative to those of G, indicating the increase in the bonding order of pyrimidine (Pyr) and imidazole rings. The (G鈥?)鈥?exhibits the characteristic CO stretching mode at 鈭?266 cm鈥? corresponding to a C鈥揙 single bond, indicating that the unpaired electron in (G鈥?)鈥?is localized on the oxygen of the Pyr ring.}