In aqueous solutions, the fluorescence of the intramolecular fluorescence resonance energy-transfer (FRET) system 1 was strongly quenched, because of close contact between the donor and acceptor moieties. FRET occurred, and the acceptor fluorescence was increased, by adding β-cyclodextrin (β-CD) to aqueous solutions of 1. Spectral analysis supported the idea that the FRET enhancement was due to the formation of an inclusion complex of the coumarin moiety in β-CD, resulting in separation of the fluorophores. On the basis of this result, we propose that covalent binding of coumarin to β-CD will provide a FRET cassette molecule. So, compound 2 bearing β-CD covalently was designed and synthesized. Fluorescence intensity of 2 was enhanced markedly compared to the intensity of 3. Applying this FRET system, various FRET probes that will be useful for ratio imaging and also the high-throughput screening will be provided.
在
水溶液中,分子内荧光共振能量转移(FRET)系统 1 的荧光被强烈淬灭,原因是供体和受体分子之间接触紧密。光谱分析支持了这一观点,即 FRET 增强是由于
香豆素分子在 β-CD 中形成了包合物,导致荧光团分离。根据这一结果,我们认为
香豆素与 β-CD 的共价结合将提供一个 FRET 盒式分子。因此,我们设计并合成了共价结合了 β-CD 的化合物 2。与 3 的荧光强度相比,2 的荧光强度明显增强。应用这种 FRET 系统,将提供各种 FRET 探针,用于比值成像和高通量筛选。