Studies on a luminescent reaction mechanism of ion-sensing bio-and chemiluminescence systems

点击翻译按钮获取中文摘要

This research project aims to establish the bioluminescence mechanism of the photoprotein aequorin(AQ)which has a calcium-ion sensing, efficient luminescence, and color-regulation properties, and to make a fundamental theory for molecular design of desirable chemiluminescent molecules. Structure elucidation of coelenteramide during AQ bioluminescence is an important problem in the bioluminescence mechanism. To clarify this problem, the fluorescent properties of the phenolate anions of coelenteramide analogues were investigated. Fluorescence of phenolate anion in non-polar solvents was observed by electronic excitation of a hydrogen-bonded complex of a coelenteramide analogue with a hydrogen-bond donor molecule. In polar solvents, phenolate anion was directly generated by using a base, and its fluorescence was studied. The se results confirm that the singlet-excited stated of phenolate anion of coelenteramide has an intramolecular CT character. The fluoro substituent effect on the fluorescent property of phenolate anions was also clarified and explained the bioluminescent pr operty of the fluorinated semi-synthetic AQ.These results consistenly support the assignment that phenolate anion is the ionic structure of the excited light-emitter in BFP during AQ bioluminescence.To establish the molecular mechanism of the lumi nescence reaction of the substrate(an imidazopyrazinone derivative)of AQ bioluminescence, we have investigated fundamental physical properties of imidazopyrazinone derivatives and their electron transfer reactivity, and found an inter molecular addition reactivity with electron-acceptor molecules. We also found that an imidazopyrazinone derivative acted as a ligand for making metal complexes. To confirm these new findings, detailed studies on the physical property and reactivity of imidazopyrazinone derivatives are in progress.