| Project/Area Number |
16310135
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
基礎ゲノム科学
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| Research Institution | Sapporo Medical University |
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Principal Investigator |
MATSUSHIMA Norio Sapporo Medical University, School of Health Sciences, Professor, 保健医療学部, 教授 (60137403)
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| Project Period (FY) |
2004 – 2006
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| Project Status |
Completed (Fiscal Year 2006)
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| Budget Amount *help |
¥6,700,000 (Direct Cost: ¥6,700,000)
Fiscal Year 2006: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 2005: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 2004: ¥4,700,000 (Direct Cost: ¥4,700,000)
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| Keywords | Helix Fitting / 3(10)-helix / α-helix / ω-helix / parahelix / solenoid structure / ヘリックスフィット / ロイシンリッチチピート(LRR) / ヴァリアント / ヘリックスフィッテイング法 / リピート配列 / ロイシンリッチリピート / 3(10)-ヘリックス |
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| Research Abstract |
The problem of fitting a helix to data arises in protein structure. A helix is described by several parameters : the helix axis, the radius and the pitch. Till now, all programs proposed have predefined one of the helix parameters. We have developed the HELFIT program for fitting helices to C^α coordinates. The 3_<10>-helix is characterized by having at least two consecutive hydrogen bonds between the main-chain carbonyl oxygen of residue i and the main-chain amide hydrogen of residue i+3. There are systematic, position-specific shifts in the backbone dihedral angles. The residues per turn and radius of regular 3_<10>-helices decrease with increasing length of helix, while the helix pitch and rise per residue increase. The fraction of regular 3_<10>-helices decreases linearly with helix length. Energy minimization; show that regular helices become less stable with increasing helix length. These findings indicate that the definition of 3_<10>-helices in terms of average, uniform dihedral angles is not appropriate and that it is inherently unstable for a polypeptide to form an extended, regular 3w-helix. We proposed that the 3_<10>-helices observed in proteins are better referred to parahelices.
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