Structural transition of human calcitonin and molecular mechanism of fibrillization

• Project/Area Number: 11680654
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Biophysics
• Research Institution: Nagaoka Universsity of Technology
• Principal Investigator: SODA Kunitsugu Nagaoka Universsity of Technology, Faculty of Engineering, 工学部, 教授 (10011686)
• Co-Investigator(Kenkyū-buntansha): 城所 俊一 長岡技術科学大学, 工学部, 助教授 (80195320)
• Project Period (FY): 1999 – 2000
• Project Status: Completed (Fiscal Year 2000)
• Budget Amount: ¥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)
• 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.

Research Products

• [Journal Article] The compact and expanded denatured conformations of apomyoglobin in the methanol-water solvent (1999)
  • Author(s): Kamatari, Y.O, 0hji, S, Konno, T, Seki, Y, Soda, K, Kataoka, M, Akasaka, K
  • Journal Title: Protein Science 8 Pages: 873-882
  • Description: 「研究成果報告書概要(和文)」より
• [Journal Article] The compact and expanded denatured conformations of apomyoglobin in the methanol-water solvent (1999)
  • Author(s): Kamatari, Y.O., Ohji, S., Konno, T., Seki, Y., Soda, K., Kataoka, M., Akasaka, K.
  • Journal Title: Protein Science 8 Pages: 873-882
  • Description: 「研究成果報告書概要(欧文)」より
• [Journal Article] Nonnative structure of proteins and implications for protein folding (1999)
  • Author(s): Soda, K., Seki, Y.
  • Journal Title: old and New Views of Protein Folding Pages: 41-50
  • Description: 「研究成果報告書概要(欧文)」より
• [Book] Nonnative structure of proteins and implications for protein folding, in "0ld and New Views of Protein Folding" (1999)
  • Author(s): Soda, K, Seki, Y.
  • Publisher: Kuwajima,K.,and Arai, M.ed.,Elsevier
  • Description: 「研究成果報告書概要(和文)」より
• [Publications] Kamatari,Y.O.,Ohji,S.,Konno,T.,Seki,Y.,Soda,K.,Kataoka,M.,and Akasaka,K.: "The compact and expanded denatured conformations of apomyoglobin in the methanol-water solvent"Protein Science. 8・4. 873-882 (1999)
• [Publications] Seki,Y.,Tomizawa,T.,Kidokoro S.and Soda,K.: "Contribution of Solvent Water to the Solution X-ray Scattering Profile of Proteins"Biophysical Chemistry. 93・2. (2001)
• [Publications] Soda K.and Seki,Y.: ""Nonnative structure of proteins and its implications for protein folding", in "Old and New Views of Protein Folding" ed.by Kuwajima,K"Elsevier Science. 10 (1999)
• [Publications] Kamatari Y.O.他: "The compact and expanded denatured conformations of apomyoglobin in the methanol-water solvent"Protein Science. 8. 873-882 (1999)
• [Publications] Soda K.: "Encyclopedia of Molecular Biology, vol. 4"Creighton, T. ed. Wiley. 2856(4) (1999)
• [Publications] Soda K.: "Old and New Views of Protein Folding"Kuwajima, K. ed. Elsevier. 318(10) (1999)