2013 Fiscal Year Final Research Report
Cold-active structure of the psychrophile enzymes
| Project/Area Number |
23580279
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Research Field |
Fisheries chemistry
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| Research Institution | Tokyo University of Marine Science and Technology |
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Principal Investigator |
ISHIDA Masami 東京海洋大学, 海洋科学技術研究科, 准教授 (80223006)
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| Co-Investigator(Kenkyū-buntansha) |
TAKANO Kazufumi 京都府立大学, 生命環境化学研究科(系), 教授 (40346185)
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| Project Period (FY) |
2011 – 2013
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| Keywords | 低温適応 / 低温菌 / トリプトファン合成酵素 / 結晶構造 / タンパク質の変性・再生 / 低温高活性 |
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| Research Abstract |
To investigate the molecular basis of cold adaptation of enzymes, we determined the crystal structure of the tryptophan synthase alpha subunit from the psychrophile Shewanella frigidimarina K14-2 and also examined its physicochemical properties. The lower stabilities against heat and denaturant of the psychrophile enzyme originated from both a faster unfolding rate and a slower refolding rate. The two-state transition of denaturation for the enzyme was highly cooperative. Relative to tryptophan synthases from other species, the psychrophile enzyme exhibited an increase in cavity volume and a decrease in the number of ion pairs. The enzyme also lacks a hydrogen bond near a loop related to catalytic function. These characteristics of the psychrophile enzyme might provide the conformational flexibility required for catalytic activity at low temperatures.
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