ヘムタンパク質の化学的改変による人工金属酵素とナノバイオ材料の開発

抄録

Hemoprotein containing heme, an iron porphyrin complex, as a cofactor is a promising scaffold toward artificial metalloenzymes and functional materials due to the unique characteristics derived from the synergetic combination of the metal cofactor and protein matrix. The obtained catalysts and materials have been expected to contribute the environmental-friendly and/or biocompatible systems in the future. In this context, our group has demonstrated artificial metalloenzymes constructed by insertion of an artificial metal cofactor into the heme-binding site of a simple hemoprotein. The artificial metalloenzymes catalyze C–H bond hydroxylation and olefin cyclopropanation and replicate the reaction of cobalamin- or F430-dependent native enzymes. The catalytic mechanisms including the intermediate detection were investigated by the spectroscopic techniques. Furthermore, hemoprotein is a useful protein to extend to the functional materials by artificial assembling forms. Especially, light harvesting systems have been constructed by hemoprotein assembly containing photosensitizers. The arrayed photosensitizers in the protein assembly are found to show energy migration, successive energy transfer among the same-type of chromophores, to collect the excited energy. A series of findings in these engineered hemoprotein systems will contribute to the materials transformation as well as artificial photosynthesis.