| Project/Area Number |
11680654
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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 |
Biophysics
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| Research Institution | Nagaoka Universsity of Technology |
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Principal Investigator |
SODA Kunitsugu Nagaoka Universsity of Technology, Faculty of Engineering, 工学部, 教授 (10011686)
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| Co-Investigator(Kenkyū-buntansha) |
城所 俊一 長岡技術科学大学, 工学部, 助教授 (80195320)
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| Project Period (FY) |
1999 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥3,700,000 (Direct Cost: ¥3,700,000)
Fiscal Year 2000: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 1999: ¥2,600,000 (Direct Cost: ¥2,600,000)
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| Keywords | calcitonin / hexafluoro-isopropanol / amyloid / protein aggregation / fibrillization / solution x-ray scattering / structural transition / α→β構造転移 / 会合体形成 / 会合体 / 立体構造転移 / 中間状態 / β-構造 |
|---|
| Research Abstract |
Dependence of the structure and aggregation of human calcitonin(hCT) on pH and concentration of alcohol, especially of hexafluoro-2-propanol (HFIP), in solution was examined by various biophysical methods. The structure of hCT in solution with a concentration of 20 μg/ml was surveyed against pH and HFIP concentration. Four structural states could be identified as the random coil, the α-helical monomer, the α-helical oligomer, and the amyloid-like aggregate. Addition of a moderate amount of HFIP was found to have remarkable effects on the aggregation of hCT. At pH【greater than or equal】4.8, aggregates are formed very rapidly in solution with a medium concentration of HFIP : At pH 7, they are formed within only several minutes after dissolving hCT in solution with 5-15% HFIP. This results from the combined effects that (1)intermolecular Coulombic repulsive forces are reduced due to decrease in the net charge on hCT, (2)addition ofa moderate concentration of HFIP stabilizes the α-helical structure of hCT necessary to initiate aggregation, but (3)resultant α-helical oligomers are not stabilized excessively so that they can be easily converted to larger aggregates. Conversely, in a neutral solution not containing HFIP, it takes more than an hour for hCT to form fibrillar aggregates even at a very high hCT concentration of 10mg/ml.
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