| Co-Investigator(Kenkyū-buntansha) |
YAMAGUCHI Hiroko Kumamoto University, Graduate School of Science and Technology, Research Associa, 大学院・自然科学研究科, 助手 (60040424)
KIDA Kenji Kumamoto University, Faculty of Engineering, Professor, 工学部, 教授 (00195306)
NISHIYAMA Katsuhiko Kumamoto University, Faculty of Engineering, Assistant Professor, 工学部, 講師 (10202243)
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| Research Abstract |
The aims of the present study are to i) prepare of optically transparent functional electrodes for Spectroelectrochemical measurements, ii) develop of new spectroelectrochemical techniques, and iii) on the basis of these developments, study on biological functions related to structural change of metalloproteins.
Preparation of functional electrodes for metalloprotein electrochemistry
We have succeeded to prepare optically transparent In_2O_3 functionalized electrodes for myoglobins and ferredoxins. The surface hydrophilicity of an In_2O_3 electrode affected very much the perk separation of the voltammogram of myoglobin, The water layr of the electrode surface may prevent from the strong adsorption of myoglobin to exclude denaturation of the protein, and also surface water would preferably take part in the redox reaction (water molecule acts as the sixth ligand of metmyoglobin). On the other hand, at positively charged polypeptide modified electrodes, for example, negatively charged ferre
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doxins showed clear voltammograms. Such surface functions as charge, hydrophilicity and strength of interaction between protein and electrode, are found to be important, but importantly the required degrees of these functions depend on the proteins and functional electrode surfaces of interest.
Development of new spectroelectrochemical techniques
Using functionalized optically transparent electrodes, in situ UV-visible, Near Infratred (NIR), circular dichroism (CD) and magnetic circular dichroism (MCD) spectroelectrochemical cells were prepared. Also, by modification of the instruments, data accumulation and automatic measurements became possible to obtain reliable and reproducible data with high S/N ratios.
Spectroelectrochemical measurements of metallopreteins
Using the developed techniques in the present study, redox reactions of cytochrome c, myoglobins, ferredoxins and their mutated molecules were examined to study in situ the dynamics of structural change during electron transfer related to biological functions of these metalloprtoteins and to monitor the bioelectrochemical reactions such as NADPH production in the presence of ferredoxin-NADP^+-reductase (FNR) using thermostable chlorella ferredoxin as a mediator. Less
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