陽子の移転によって引き起こされる形状の変化と,ガス相における設計ペプチドの溶解
Motoya Kohtani1, Thaddeus C Jones, Rajagopalan Sudha
1Department of Chemistry, Indiana University, 800 East Kirkwood Avenue, Bloomington, Indiana 47405, USA.
Journal of the American Chemical Society
|June 1, 2006
まとめ
ペプチドの形状は,陽子の移転により,温度によって変化します. アルギニン・アラニン・ライシン (RAK) とアルギニン・アラニン・ヒスティジン (RAH) ペプチドは,温度に依存するヘリックス・グローブルの移行とヘリックス溶解を示します.
科学分野:
- バイオフィジックス 生物物理学
- コンピューティング・ケミストリー
- タンパク質科学 タンパク質科学
背景:
- ペプチドは,アミノ酸の短い鎖である.
- プロトンの移転はペプチド構造に影響を与えることができます.
- ペプチドの構成を理解することは,タンパク質の折りたたみの鍵です.
研究 の 目的:
- 陽子化されたアルギニン・アラニン・ライシン (RAK) とアルギニン・アラニン・ヒスティジン (RAH) ペプチドの温度依存構造を調べる.
- 構造変化を誘発する分子内プロトン伝達の役割を調査する.
- ヘリックス - 球体移行とヘリックス溶融現象を特徴づけるために.
主な方法:
- 温度変化を用いたプロトンペプチド (RA15K,RA20K,RA15H) のガス相構成分析.
- 400K以下で動力的に制御された構造変遷の観測.
- ヘリックス - 球球の移行と,500 K 辺りのヘリックス溶融の分析.
主要な成果:
- 動力的に制御された移行が観察されました:RA15Hではヘリックスから球体へ,RA15KとRA20Kでは球体からヘリックスへ,400K以下です.
- 球体の形状は膨張し,より高い温度でエントロピー的に有利になる.
- RA15KとRA20Kのヘリコプターは,500 Kの周りで広範な融解の移行を経験し,ペプチドサイズが増加するにつれて狭くなっています.
- 二重陽子を持つRA15Kは,残基の排斥による高温下ではダンベル状の形状を示している.
結論:
- 分子内プロトン伝搬は,これらのペプチドの構造変化の主要な原動力である.
- 温度がペプチド構造に大きく影響し,膨張した状態とエントロピカルに駆動された球状状態を好む.
- ペプチドのサイズは,ヘリックス溶解の協力性に影響し,より大きなペプチドはより狭い移行を示します.
- 陽子の移動性は,螺旋形状の融解移行に関与している可能性が高い.
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