運動と熱力学的制御のバランスをとる:スクワレンサイクラースによるカルボケーションサイクル化のメカニズム
1Department of Chemistry and Supercomputing Institute, University of Minnesota, Minneapolis, Minnesota 55455, USA.
Journal of the American Chemical Society
|October 16, 2003
まとめ
スクアレンホーペンサイクラス (SHC) は,QM/MMポテンシャルを使用して,カルボケーションサイクライゼーションをシミュレートします. 運動制御は製品分布を決定し,他の経路よりもホパノイドの形成を好む.
科学分野:
- バイオケミストリー バイオケミストリー
- コンピューティング・ケミストリー
- 酵素学 酵素学とは
背景:
- スクアレンホーペンサイクラゼ (SHC) は,複雑なサイクリング反応を触媒化する.
- ホパノイド生物合成のメカニズムを理解することは,生化学において極めて重要です.
研究 の 目的:
- スクアレンからホーペンへのサイクリングの分子ダイナミクスを研究する.
- SHC内のカルボケーションサイクルメカニズムを解明する.
- 製品の流通を制御する要因を決定する.
主な方法:
- 組み合わせた量子力学および分子力学 (QM/MM) の潜在力.
- 自由エネルギーのシミュレーションと自由エネルギーの表面構築.
- 分子力学シミュレーション. 分子力学シミュレーション.
主要な成果:
- カーボケーションサイクルカスケードは,熱力学と運動制御のバランスをとる.
- 5~6つの環の膨張は,C環やD環の形成に適した経路ではない.
- 2つの非同期的な協調した経路は,A/B-バイサイクルサイクロヘキシルカチオン中間体から発生します.
- これらの経路は,異なる四環および五環ホパノイド骨格につながります.
結論:
- 野生型のSHCにおける製品の配布は,運動制御によって管理されます.
- ペンタサイクルのホパノイドの99%の産量は,運動的好意性によって説明されます.
- このメカニズムは,複雑な天然産物の生物合成に対する複雑な制御を強調しています.
関連する概念動画
ATP Driven Pumps I: An Overview
ATP-driven pumps, also known as transport ATPases, are integral membrane proteins. They have binding sites for ATP located on the membrane's cytosolic side and the ion-conducting domain in the transmembrane region. These pumps use the free energy released from ATP hydrolysis to move the solutes across cell membranes against an electrochemical gradient.
There are four main types of ATP-driven pumps - P-type, V-type, F-type, and ABC transporter. All these pumps are of varying complexities and are...
There are four main types of ATP-driven pumps - P-type, V-type, F-type, and ABC transporter. All these pumps are of varying complexities and are...
Regulation of Metabolism
Cellular needs and conditions vary from cell to cell and change within individual cells over time. For example, the required enzymes and energetic demands of stomach cells are different from those of fat storage cells, skin cells, blood cells, and nerve cells. Furthermore, a digestive cell works much harder to process and break down nutrients during the time that closely follows a meal compared with many hours after a meal. As these cellular demands and conditions vary, so do the amounts and...
Non-equilibrium in the Cell
An important concept in studying metabolism and energy is that of chemical equilibrium. Most chemical reactions are reversible. They can proceed in both directions, releasing energy into their environment in one direction, and absorbing it from the environment in the other direction. The same is true for the chemical reactions involved in cell metabolism, such as the breaking down and building up of proteins into and from individual amino acids, respectively. Reactants within a closed system...
Introduction to Mechanisms of Enzyme Catalysis
For many years, scientists thought that enzyme-substrate binding took place in a simple "lock-and-key" fashion. This model stated that the enzyme and substrate fit together perfectly in one instantaneous step. However, current research supports a more refined view scientists call induced fit. The induced-fit model expands upon the lock-and-key model by describing a more dynamic interaction between enzyme and substrate. As the enzyme and substrate come together, their interaction causes a mild...
Introduction to Mechanisms of Enzyme Catalysis
For many years, scientists thought that enzyme-substrate binding took place in a simple "lock-and-key" fashion. This model stated that the enzyme and substrate fit together perfectly in one instantaneous step. However, current research supports a more refined view scientists call induced fit. The induced-fit model expands upon the lock-and-key model by describing a more dynamic interaction between enzyme and substrate. As the enzyme and substrate come together, their interaction causes a mild...
Bioreactor Controls-I
Maintaining optimal conditions within fermenters is essential for maximizing microbial productivity and ensuring process efficiency. This lesson focuses on key parameters—temperature, foam, pH, carbon dioxide, oxygen, and pressure—and their precise measurement and control strategies in fermentation systems.Temperature ControlTemperature regulation is critical due to the exothermic nature of many fermentation processes. In small laboratory fermenters, temperature is commonly monitored using...


