Zhang C, Zhao Y, Cui M, Cui X, Zhang C, Meng Q. Simulation for fluorescence detection of O4-methylthymidine with definite photophysical characteristics.
SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2023;
296:122691. [PMID:
37023654 DOI:
10.1016/j.saa.2023.122691]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 03/12/2023] [Accepted: 03/28/2023] [Indexed: 06/19/2023]
Abstract
DNA alkylation is caused by long-term exposure of cells to the environmental and endogenous alkylating agents, which can also lead to DNA mutations and therefore trigger some cancers. Since O4-methylthymidine (O4-meT), mismatched with guanine (G), is the most common but not easily repaired alkylated nucleoside, monitoring O4-meT can help to effectively reduce the occurrence of carcinogenesis. In this work, the modified G-analogues are selected as the fluorescence probe to monitor the existence of O4-meT according to its pairing characteristics. The photo-physical properties of considered G-analogues formed by ring expansion or addition of fluorophores were studied in detail. It is found that, compared with natural G, the absorption peaks of these fluorescence analogues are red-shifted (>55 nm) and the luminescence is enhanced by π-conjugation. Especially, the xG has a large Stokes shift (65 nm) with fluorescence insensitive to natural cytosine (C) and retains efficient emission after pairing, while it is sensitive to O4-meT and the quenching phenomenon occurs due to the excited state intermolecular charge transfer. Accordingly, the xG can be used as a fluorescent probe to identify the O4-meT in solution. In addition, the direct use of deoxyguanine fluorescent analogue for monitoring O4-meT was evaluated by the effects of ligating deoxyribose on absorption and fluorescence emission.
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