Co-Investigator(Kenkyū-buntansha) |
NISHIDE Hiroyuki Waseda Univ., School of Sci.& Eng., Dept.of Polymer Chem.Professor, 理工学部, 教授 (90120930)
KOMATSU Teruyuki Waseda Univ., Ady.Res.C.Sci.& Eng., Researcher, 理工学総合研究センター, 客員研究員
TAKEOKA Shinji Waseda Univ.School of Sci.& Eng., Dept.of Polymer Chem., Lecturer, 理工学部, 専任講師 (20222094)
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Research Abstract |
Ten amphiphilic derivatives of tetraphenylporphyrin or protoporphyrin were synthesized, and their molecular assembling structures such as vesicles and fibers were analyzed with microscopic (TEM,cryo-TEM,SEM), and spectroscopic (UV-Vis., fluorescence) measurements. Especially, the microstructures of porphyrin ring such as accumulation and orientation were clarified by calculation with an exiton-coupling model. A main factor to make lipidporphyrin assemblies was concluded to be hydrophilic-hydrophobic balance and tertiary molecular structure of porphyrin as well as solution conditions. From the construction of the matrix by self-assembling of lipidporphyrin derivatives, the prevention of the inner-sphere electron transfer at metal-complex site become possible, and thus stable oxygen-binding complex was formed in the physiological condition. Especially, oxygen-binding complex could be formed firstly by molecular assembling phenomena even for the heme with no specific bulky substituents.Fro
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m the analyzes of oxygen coordination process with laser flash time-resolved photometry, the degree of oxygen-affinity was clarified to be regulated by controlling electron density of central iron by electron donation from coordinated base at a fifth coordination site. Lipidprotoporphyrin was incorporated spontaneously into the bilayr membrane of the phospholipid vesicles. The fact that four-substituted protoporphyrin derivatives did not form the mu-oxo dimer in bilayr membrane. That leads to the realization of oxygen-binding complex of protoporphyrin derivatives due to the regulation of electronic process at complex site. The oxygen-coordination equilibrium of protoheme was controlled by gel-to-liquid crystalline phase transition temperature of the bilayr. Furthermore, in the care of porphyrin assembly, molecules were recognized by molecular packing states and it was clarified kinetically that electron transfer with high selectivity occurred from the excited triplet state. In conclusion, the electron process and control of molecular interaction were made possible by the formation of porphyrin assemblies. Less
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