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

本研究旨在建立具有钙离子敏感、高效发光和颜色调节特性的发光蛋白水母发光蛋白（AQ）的生物发光机制，并为理想的水母发光分子的分子设计提供基础理论。腔肠酰胺生物发光过程中的结构解析是生物发光机理研究中的一个重要问题。为了澄清这个问题，研究了腔肠酰胺类似物的酚阴离子的荧光性质。本文报道了在非极性溶剂中，用电子激发的方法，观察到一种由一种腔肠酰胺类似物与一种氢键供体分子形成的氢键复合物中酚根离子的荧光。在极性溶剂中，用碱直接生成酚根阴离子，并研究了其荧光性质。结果表明，腔肠酰胺酚根阴离子的单重激发态具有分子内CT特征。进一步阐明了含氟取代基对酚阴离子荧光性质的影响，并解释了含氟半合成AQ的生物发光性质，这些结果一致支持了AQ生物发光过程中酚阴离子是BFP中受激发光体的离子结构的论断，建立了底物发光反应的分子机理（一种咪唑并吡嗪酮衍生物）生物发光的基础上，我们研究了咪唑并吡嗪酮衍生物的基本物理性质及其电子转移反应性，发现了与电子受体分子的分子间加成反应。我们还发现，咪唑并吡嗪酮衍生物作为一个配体，使金属配合物。为了证实这些新发现，正在对咪唑并吡嗪酮衍生物的物理性质和反应性进行详细的研究。

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.