ピラノース環の移行状態は,セルロビオヒドローラゼI誘導による構成安定性とグリコシド結合の極化から派生しています
Christopher B Barnett1, Karl A Wilkinson, Kevin J Naidoo
1Scientific Computing Research Unit and Department of Chemistry, University of Cape Town, Rondebosch 7701, South Africa.
Journal of the American Chemical Society
|August 28, 2010
まとめ
炭水化物のリングパッカーは,薬物と材料の設計に影響を与えます. 新しいシミュレーションでは,タンパク質結合が異常なグルコピラノース環形構造を安定させ,グリコシル化反応を誘導することを明らかにしています.
科学分野:
- 計算化学はコンピュータ化学である.
- バイオフィジックス 生物物理学
- 炭水化物の化学反応
背景:
- 炭水化物のリングパッカーは,材料と医薬品の合理的な設計に不可欠です.
- 多次元の自由エネルギー景観の正確な計算は,計算的に困難です.
研究 の 目的:
- 適応反応座標力からの自由エネルギー (FEARCF) の新しい方法を適用して,多次元リングパッカーの自由エネルギーを計算する.
- 異なる環境 (真空,水,タンパク質) でセルロオリゴサハリド内のグルコピラノース環の構成上の好みを調査する.
主な方法:
- アダプティブ・リアクション・コーディネート・フォース (FEARCF) の自由エネルギー法を利用した.
- SCC-DFTB QM/MM ノン-ボルツマンシミュレーションを実施しました.
- セルロオリゴサッカライドにおけるグルコピラノース環パックリングの計算された自由エネルギー風景.
主要な成果:
- タンパク質の環境は,典型的な (4) C 型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型 (4) E 型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型型
- タンパク質の触媒部位内の (4) H (((3) 形状において,有意な電子の再編成が観察されました.
- これらの再配置は,グリコシル化反応の移行状態を促進します.
結論:
- FEARCFメソッドは,多次元リングパッカーの自由エネルギーの正確な計算を可能にします.
- タンパク質結合は,炭水化物の環形構造に大きく影響し,酵素活性に影響します.
- タンパク質によって引き起こされるこれらの構成変化を理解することは,効果的なグリコシライゼーション阻害剤と触媒を設計するための鍵です.
関連する概念動画
01:28Stability of Conjugated Dienes
Introduction
A comparison of the enthalpies of hydrogenation of dienes reveals that conjugated dienes release less heat on hydrogenation, rendering them more stable than their nonconjugated analogs.
A comparison of the enthalpies of hydrogenation of dienes reveals that conjugated dienes release less heat on hydrogenation, rendering them more stable than their nonconjugated analogs.
01:17Thermal Electrocyclic Reactions: Stereochemistry
The stereochemistry of electrocyclic reactions is strongly influenced by the orbital symmetry of the polyene HOMO. Under thermal conditions, the reaction proceeds via the ground-state HOMO.
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.
02:02Chair Conformation of Cyclohexane
The chair conformation is the most stable form of cyclohexane due to the absence of angle and torsional strain. The absence of angle strain is a result of cyclohexane’s bond angle being very close to the ideal tetrahedral bond angle of 109.5° in its chair conformer. Similarly, the torsional strain is also absent owing to the perfectly staggered arrangement of bonds.
The hydrogen atoms linked to carbons are arranged in two different axial and equatorial orientations to achieve this staggered...
The hydrogen atoms linked to carbons are arranged in two different axial and equatorial orientations to achieve this staggered...
01:57Preparation of Diols and Pinacol Rearrangement
Compounds bearing two hydroxyl groups are known as diols. When the hydroxyl groups are located on adjacent carbon atoms, the diols are called vicinal diols or glycols. Under acidic conditions, vicinal diols undergo a specific reaction called pinacol rearrangement.
The reaction begins with transferring a proton from the acid catalyst to one of the hydroxyl groups, producing an oxonium ion.
The reaction begins with transferring a proton from the acid catalyst to one of the hydroxyl groups, producing an oxonium ion.
01:26Thermal and Photochemical Electrocyclic Reactions: Overview
Electrocyclic reactions are reversible reactions. They involve an intramolecular cyclization or ring-opening of a conjugated polyene. Shown below are two examples of electrocyclic reactions. In the first reaction, the formation of the cyclic product is favored. In contrast, in the second reaction, ring-opening is favored due to the high ring strain associated with cyclobutene formation.
02:34Regioselectivity and Stereochemistry of Acid-Catalyzed Hydration
The rate of acid-catalyzed hydration of alkenes depends on the alkene's structure, as the presence of alkyl substituents at the double bond can significantly influence the rate.