2007 Fiscal Year Final Research Report Summary
Engineering of proteins from thermophilic bacteria as a scaffold for thermally tolerant artificial enzyme
| Project/Area Number |
18560753
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Biofunction/Bioprocess
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| Research Institution | Nagoya University |
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Principal Investigator |
NAKAJIMA Hiroshi Nagoya University, School of Srience, Associate Professor (00283151)
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| Project Period (FY) |
2006 – 2007
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| Keywords | Cytochrome c_<552> / Myoglobin / Thermophile / Peroxidase / Heme Proteins / Thermus thermophirus |
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| Research Abstract |
A final goal of the present research project is to construct thermally tolerant proteins applicable to practical use by engineering constitutively heat resistant (and therefore highly stable) proteins from thermophile. One of the major achievements of the project is engineered cytochrome C_552 (Cyt c_552) acquiring the peroxidase activity. Cyt c_552 is a heme protein deriving from Thermus thermophilus. Engineered Cyt c552 on the basis of the catalytic mechanism of natural peroxidases shows durable catalytic activity even at 70 ℃, which is distinctive to natural ones that work at around normal temperature and are deactivated at 40 to 50 ℃ due to denaturation. Although the catalytic activity of the engineered Cyt c_552 is still lower than that of natural ones, increasing activity at the higher temperature shows potential of the engineered Cyt c_552 as a thermally tolerant artificial peroxidase. Close inspection to the catalytic reaction mechanism of the engineered Cyt c_552 gives some principles of how to improve the catalytic activity by site-directed mutagenesis, which will be achieved in future studies to develop the present artificial peroxidase.
Results obtained in the project demonstrate that the engineering of proteins from thermophiles based on molecular mechanisms of desired functions is a potent methodology to construct artificial proteins that are enough stable and durable in practical use. This may shed a light on common proteins that have been found in extremophile but never been focused due to lack of specific function, and promote usage as versatile protein resources for protein engineering aspiring practical use.
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