Intramolecular fluorescence resonance energy transfer system with coumarindonor included in beta-cyclodextrin

摘要

In aqueous solutions, the fluorescence of the intramolecular fluorescence resonance; energy-transfer (FRET) system 1 mas strongly quenched, because of close contact between the donor and acceptor moieties, FRET occurred, and the acceptor fluorescence was increased, by adding beta -cyclodextrin (beta -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 beta -CD, resulting in separation of the fluorophores, On the basis of this result, we propose that covalent binding of coumarin to beta -CD will provide a FRET cassette molecule. So, compound 2 bearing beta -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.