期刊
JOURNAL OF PHYSICAL CHEMISTRY B
卷 123, 期 13, 页码 2904-2914出版社
AMER CHEMICAL SOC
DOI: 10.1021/acs.jpcb.9b02361
关键词
-
资金
- ERC [CAPRI 290966]
- Deutsche Forschungsgemeinschaft through the Collaborative Research Centre 677 Function by Switching
- DFG [RO 4952/1-1]
- EPSRC
The fluorescent analogue 2-aminopurine (2AP) of the canonical nucleobase adenine (6-aminopurine) base-pairs with thymine (T) without disrupting the helical structure of DNA. It therefore finds frequent use in molecular biology for probing DNA and RNA structures and conformational dynamics. However, detailed understanding of the processes responsible for fluorescence quenching remains largely elusive on a fundamental level. Although attempts have been made to ascribe decreased excited-state lifetimes to intrastrand charge-transfer and stacking interactions, possible influences from dynamic interstrand H-bonding have been widely ignored. Here, we investigate the electronic relaxation of UV-excited 2AP center dot T in Watson Crick (WC) and Hoogsteen (HS) conformations. Although the WC conformation features slowed-down, monomer-like electronic relaxation in tau similar to 1.6 ns toward ground-state recovery and triplet formation, the dynamics associated with 2AP center dot T in the HS motif exhibit faster deactivation in tau similar to 70 ps. As recent research has revealed abundant transient interstrand H-bonding in the Hoogsteen motif for duplex DNA, the established model for dynamic fluorescence quenching may need to be revised in the light of our results. The underlying supramolecular photophysical mechanisms are discussed in terms of a proposed excited-state double-proton transfer as an efficient deactivation channel for recovery of the HS species in the electronic ground state.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据