高解像度1Hと13Cの固体NMRスペクトロスコーピーによる天然の同位体の豊富さでのグアノシン自己組成の特定
Amy L Webber1, Stefano Masiero, Silvia Pieraccini
1Department of Physics, University of Warwick, Coventry CV4 7AL, United Kingdom.
Journal of the American Chemical Society
|November 1, 2011
まとめ
固体NMRは,リボンやクォーテットのようなグアノシン誘導体の自己組み立て構造を特定します. この方法は,NH··NとNH··Oの水素結合を区別し,結晶のない構造分析を助けます.
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.
- 超分子化学 超分子化学
- グアノシン誘導体自己組み立て
背景:
- グアノシン誘導体は自己組み立て構造を形成できますが,単一結晶なしでこれらの構造を決定することは困難です.
- 以前の研究では,構造の解明のために同位体ラベルと微分を用いた.
- 異なる自己組み立てモチーフ (例えば,リボン型対四重奏型) を区別するには,繊細な分析方法が必要です.
研究 の 目的:
- グアノシン誘導体の自己組み立て構造を特定するために,同位素で標識されていない固体NMR方法を開発し,適用する.
- 光スペクトルの特徴に基づいて,リボン型とクォーテット型の自己組み立てを区別する.
- NMRの発見を既知の構造データと計算上の予測と相関させる.
主な方法:
- 陽子対陽子の近接は,陽子対二量子 (DQ) 結合回転と多発パルススペクトロスコーピー (CRAMPS) の固体NMR相関スペクトルを使用して特定されました.
- (1) Hの化学的シフト,特にNHとNH (2) の共鳴の分析.
- スペクトル割り当てのためのゲージを含むプロジェクター強化波 (GIPAW) の化学シフト計算.
- (14) 急速な魔法角度回転 (MAS) によるN−1H相関スペクトルを使用した.
主要な成果:
- 明確なスペクトル指紋は,ラベルのないグアノシン誘導体におけるリボン状および四重奏状の自己組み立てのために観察されました.
- リボン状の構造におけるNHのより高い (1) H化学的シフト (13−15 ppm) は,NH··O水素結合を示し,四重奏状の構造 (NH···N) の場合は10−11 ppmである.
- NH(2) (1) Hの化学シフトの逆順序で,2つの組立型を区別する.
- 割り当てはGIPAW計算と (14) N-(1) H相関スペクトルを使用して確認され,より広い範囲の近接が明らかになりました.
結論:
- 固体NMR,特にDQ CRAMPSは,同位体ラベルなしでグアナシン誘導体の自己組み立て構造を特定するのに有効です.
- NMRのスペクトル特性は,NHの化学的シフトとNH ((2)) の共振配列を含むが,リボン型と四重奏型の配列を確実に区別する.
- この研究は,単一結晶が利用できない困難なケースにおいて,超分子構造の決定のための強力なツールを提供します.
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