15N グリシルトリペプチドの化学遮蔽:固体NMRによる測定とX線構造との相関
Eduard Y Chekmenev1, Qianwen Zhang, Kevin W Waddell
1Department of Chemistry, 2320 South Brook Street, University of Louisville, Louisville, Kentucky 40292, USA.
Journal of the American Chemical Society
|January 8, 2004
まとめ
この研究では,さまざまなペプチド構造のグリシル残基における15N化学シールドについて詳細に説明しています. 発見は,水素結合と構成がこれらのシールドパラメータにどのように影響し,二次構造の予測を可能にするかを明らかにします.
科学分野:
- 固体核磁共振 (NMR) スペクトロスコーピーは,固体核磁共振 (NMR) スペクトロスコーピーを用います.
- 構造生物学 構造生物学とは
- コンピューティング・ケミストリー
背景:
- グリチル残基は,ペプチドやタンパク質の基本的な構成要素である.
- 化学シールドと二次構造の関係を理解することは,タンパク質構造の決定に不可欠です.
- 以前の研究では,さまざまなスペクトルパラメータが調査されていますが,さまざまなグリシル構成の15Nシールドの包括的な分析は欠けていました.
研究 の 目的:
- 異なる二次構造 (アルファヘリックス,ベータ鎖,ポリグリシンII,および拡張) のグリシル残留物の15N化学シールドパラメータを正確に決定する.
- 15Nシールドに対する水素結合と局所形状の影響を調査する.
- 遮蔽パラメータに基づいて,グリシル残基二次構造の予測モデルを開発する.
主な方法:
- 固体マジック・アングル・スピニング (MAS) と静止型NMRスペクトロスコーピーを採用した.
- 合成されたペプチドは,同位体として標識された[2-(13) C,(15) N]Glyを含む.
- 2次元の二極結合,特に (1) H - 15 N と (13) C - 15 N を用いて,分子枠内の 15 N 遮断テンソルを方向付けました.
主要な成果:
- 精密な15N化学シールド成分 (2-5ppm) がグリシル残留物のために決定されました.
- 15Nシールドテンソーのデルタ ((11),デルタ ((33)) 平面はペプチド平面と不一致であることが判明しました.
- イソトロピックシフトは13ppmの変動があり,水素結合と形状と相関しており,テンソールスペンと軸対称性からの偏差は二次構造によってグループ化されました.
結論:
- 15N化学シールドのパラメータは,グリシル残留物の局所的構成と水素結合に敏感です.
- 15Nシールドテンソーの方向性は,局所分子幾何学についての洞察を提供します.
- 保護パラメータを使用して,タンパク質におけるグリシル残基二次構造の予測スキームを確立し,既存の (13) C ((alpha)) データを補完することができます.
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