1996 Fiscal Year Final Research Report Summary
Interfacial Electron Transfer of Metalloproteins -Design of Functional Electrode Surfaces and Its Application in Bioelectrochemistry-
| Project/Area Number |
06045042
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| Research Category |
Grant-in-Aid for international Scientific Research
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| Allocation Type | Single-year Grants |
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| Section | University-to-University Cooperative Research |
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| Research Institution | Kumamoto University |
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Principal Investigator |
TANIGUCHI Isao Faculty of Engineering, Kumamoto University, Professor, 工学部, 教授 (90112391)
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| Co-Investigator(Kenkyū-buntansha) |
FARRELL Nich バージニアコモンウエルス大学, 化学科, 準教授
CHELEBOWSKI Jan F Department of Biochemistry, Virginia Commonwealth University, 化学科, 教授
HAWKRIDGE Fred M Department of Chemistry, Virginia Commonwealth University, 化学科, 教授
KIDA Kenji Faculty of Engineering, Kumamoto University, 工学部, 教授 (00195306)
NISHIYAMA Katsuhiko Faculty of Engineering, Kumamoto University, 工学部, 講師 (10202243)
FARRELL Nicholas P Department of Chemistry, Virginia Commonwealth University
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| Project Period (FY) |
1994 – 1996
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| Keywords | Metalloprotein / Interfacial electron transfer / Single crystal / Functional electrode / Spectroelectrochemical technique / Biocatalytic reaction / Circular dichroism / Digital simulation |
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| Research Abstract |
In the present study, electron transfer reactions of metalloproteins at functional electrodes have been examined to understand biofunctions of metalloproteins and to develop various bioelectrochemical reactions.
1. Interfacial electron transfer reactions of metalloproteins and their bioelectrochemical applications :
(1) Functional electrodes for rapid electron transfer of metalloproteins have been developed. (2) At the highly hydrophilic indium oxide electrode, some artificially modified myoglobin molecules have been studied. (3) For cytochrome c, clear effect of the structure of the modifier adsorbed onto gold single crystal surfaces on the electrochemical responses was observed. (4) Amino acid residues of ferredoxin have clearly shown to have their own distinguished roles for biological functions, such as controlling the redox potential and the complex formation with enzymes.
2. Dynamics of structural change of metalloproteins :
(1) Stopped-flow circular dichroism (CD) spectroelectrochem
… More
ical techniques has been developed. (2) Both cytochrome c and ferredoxin changed their structures by steps during electron transfer, and (3) some kinetic data of structural changes were obtained. (4) A fine structural change as a function of temperature was suggested for ferredoxin.
3. Application of ferredoxin electrochemistry to develop artificial photosynthetic reactions :
(1) Electrochemically reduced ferredoxin was applicable as an electron transfer mediator to develop new bioelectrocatalytic reactions as in nature. For example, L-malic acid was obtained with carbon dioxide fixation in the presence of ferredoxin-NADP^+-reductase and malic enzyme. L-glutamic acid was also obtained from oxoglutaric acid with by introducing of ammonia, and (2) their reactions were analyzed by using a digital simulation technique.
4. Semi-artificially designed metalloproteins :
(1) New biological functions have been found using semi-artificially reconstituted myoglobin molecules. (2) Computer calculation of the structure of ferredoxin showed that the modification of Ser-46 to Gly-46 introduced rather large distortion of the iron sulfur cluster, causing a large positive shift in redox potential. Less
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