在酶的活性位点上,什么触发了质子转移和电子转移的合?
1School of Chemistry, UNSW Sydney, NSW 2052, Australia. i.dance@unsw.edu.au.
Dalton transactions (Cambridge, England : 2003)
|April 23, 2024
概括
酶酶使用电子转移来激活铁合因子 (FeMo-co) 中的硫原子,使合成的质子转移成为可能. 这种由电子触发的质子转移机制对于固定至关重要.
科学领域:
- 生物化学 生物化学
- 生物有机化学 生物有机化学
- 计算化学计算化学
背景情况:
- 酶利用8个电子和8个质子催化N2转化为NH3.
- 电子转移发生在Fe蛋白到含有FeMo辅因子的MoFe蛋白之间.
- 建议通过质子线机制将质子转移到FeMo-co.
研究的目的:
- 为了研究酶中质子合电子转移 (PCET) 的机制.
- 阐明FeMo辅因子对电子的添加如何影响质子转移.
- 为电子转移在触发质子运动中的作用提供计算证据.
主要方法:
- 在添加电子时,集群电荷分布的量子化学计算.
- 对质子转移动态和能量障碍的计算.
- 对电子-质子合机制的分析.
主要成果:
- 添加到FeMo-co的电子将硫原子的负电荷定位,增加了它们的基本性.
- 计算显示减少了质子转移障碍 (约. 3.5 kcal mol-1) 和增加了产品的稳定性 (大约. 7 kcal mol-1) 在添加电子时.
- 质子道可能发生,电子转移被确定为质子转移的触发因素.
结论:
- 该研究提供了在酸酶中电子触发的质子转移的详细机制.
- 计算结果支持硫基度增加在促进质子化中的作用.
- 这项工作阐明了固催化循环中的一个关键步骤.
相关概念视频
Electron Transport Chain: Complex III and IV
7.4K
During the electron transport chain, electrons from NADH and FADH2 are first transferred to complexes I and II, respectively. These two complexes then transfer the electrons to ubiquinol, which carries them further to complex III. Complex III passes the electrons across the intermembrane space to Cyt c, which carries them further to complex IV. Complex IV donates electrons to oxygen and reduces it to water. As electrons pass through complexes I, III, and IV, the energy released aids the pumping...
7.4K
Rate-Determining Steps
32.3K
Relating Reaction Mechanisms
In a multistep reaction mechanism, one of the elementary steps progresses significantly slower than the others. This slowest step is called the rate-limiting step (or rate-determining step). A reaction cannot proceed faster than its slowest step, and hence, the rate-determining step limits the overall reaction rate.
The concept of rate-determining step can be understood from the analogy of a 4-lane freeway with a short-stretch of traffic-bottleneck caused due to...
In a multistep reaction mechanism, one of the elementary steps progresses significantly slower than the others. This slowest step is called the rate-limiting step (or rate-determining step). A reaction cannot proceed faster than its slowest step, and hence, the rate-determining step limits the overall reaction rate.
The concept of rate-determining step can be understood from the analogy of a 4-lane freeway with a short-stretch of traffic-bottleneck caused due to...
32.3K
Electrophilic Aromatic Substitution: Nitration of Benzene
5.9K
The nitration of benzene is an example of an electrophilic aromatic substitution reaction. It involves the formation of a very powerful electrophile, the nitronium ion, which is linear in shape. The reaction occurs through the interaction of two strong acids, sulfuric and nitric acid.
5.9K
1° Amines to Diazonium or Aryldiazonium Salts: Diazotization with NaNO2 Mechanism
3.8K
Nitrous acid is a relatively weak and unstable acid prepared in situ by the reaction of sodium nitrite and cold, dilute hydrochloric acid. In an acidic solution, the nitrous acid undergoes protonation when it loses water to form a nitrosonium ion—an electrophile. Nitrous acid reacts with primary amines to give diazonium salts. The reaction is called diazotization of primary amines.
3.8K
Nitriles to Carboxylic Acids: Hydrolysis
3.8K
Nitriles undergo acid-catalyzed hydrolysis or base-catalyzed hydrolysis to form a carboxylic acid. These reactions proceed via an amide intermediate.
3.8K
ATP Synthase: Structure
12.3K
ATP synthase or ATPase is among the most conserved proteins found in bacteria, mammals, and plants. This enzyme can catalyze a forward reaction in response to the electrochemical gradient, producing ATP from ADP and inorganic phosphate. ATP synthase can also work in a reverse direction by hydrolyzing ATP and generating an electrochemical gradient. Different forms of ATP synthases have evolved special features to meet the specific demands of the cell. Based on their specific feature, ATP...
12.3K
![Protein Film Infrared Electrochemistry Demonstrated for Study of H2 Oxidation by a [NiFe] Hydrogenase](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F55858.jpg&w=3840&q=50)

