在预处理的银糖氧化酶中减少的铜活性位点的结构:在辅因子生物发生过程中为单电子O2激活的连接物调整
Ryan E Cowley1, Jordi Cirera1, Munzarin F Qayyum1
1Department of Chemistry, Stanford University , Stanford, California 94305, United States.
Journal of the American Chemical Society
|September 15, 2016
概括
银氧化酶 (GO) 的生物发生涉及铜和氧. 这项研究揭示了铜如何促进氧气激活和辅助因子的形成.
科学领域:
- 生物化学
- 酵素学
- 生物有机化学
背景情况:
- 银糖氧化酶 (GO) 是一种依赖铜的酶,对基质氧化至关重要.
- 它使用一种独特的化氨酸 (Cys-Tyr) 氧化还原因子.
- 辅因子生物发生是一个依赖铜和氧的转化后过程.
研究的目的:
- 阐明GO中Cys-Tyr辅因子生物发生的机制.
- 研究铜在生物发生过程中的氧激活作用.
- 了解Cys-Tyr交叉连接形成的结构和电子因素.
主要方法:
- 边缘附近的X射线吸收结构 (XANES) 光谱测定Cu(I) 负载的GO的活性位点结构.
- 扩展的X射线吸收细结构 (EXAFS) 光谱用于详细的结构分析.
- 密度功能理论 (DFT) 计算以建模反应机制.
主要成果:
- 活性部位的氨酸降低了铜潜能,促进了O2的降低.
- 由此产生的Cu(II) 超氧化物中间体被激活,从囊中提取原子.
- 铜协调促进了氨酸脱质和Cys-Tyr交叉链的形成.
结论:
- 铜 (I) 在通过1e-降解实现O2激活方面发挥着关键作用.
- 铜 (II) 中间体对于激活基质 (半氨酸) 形成交叉链是必不可少的.
- 这项研究揭示了GO Cys-Tyr辅因子自处理生物发生的关键机制步骤.
更多相关视频
相关概念视频
Voltaic/Galvanic Cells
67.6K
Spontaneous Chemical Reactions
Spontaneous redox reactions occur abundantly in nature. The chemical reaction occurring in a disposable AA battery powering our remote controls is one such example of a spontaneous redox reaction. Another example is the immersion of coiled copper wire into an aqueous silver nitrate solution. The reaction shows a gradual, visually impressive color change from colorless to bright blue and the formation of a grey precipitate on the copper wire. In this experiment,...
Spontaneous redox reactions occur abundantly in nature. The chemical reaction occurring in a disposable AA battery powering our remote controls is one such example of a spontaneous redox reaction. Another example is the immersion of coiled copper wire into an aqueous silver nitrate solution. The reaction shows a gradual, visually impressive color change from colorless to bright blue and the formation of a grey precipitate on the copper wire. In this experiment,...
67.6K
Electron Transport Chain: Complex III and IV
9.6K
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...
9.6K
Enzymes
96.5K
Inside living organisms, enzymes act as catalysts for many biochemical reactions involved in cellular metabolism. The role of enzymes is to reduce the activation energies of biochemical reactions by forming complexes with its substrates. The lowering of activation energies favor an increase in the rates of biochemical reactions.
Enzyme deficiencies can often translate into life-threatening diseases. For example, a genetic abnormality resulting in the deficiency of the enzyme G6PD...
Enzyme deficiencies can often translate into life-threatening diseases. For example, a genetic abnormality resulting in the deficiency of the enzyme G6PD...
96.5K
Oxidation and Reduction of Organic Molecules
9.9K
Energy production within a cell involves many coordinated chemical pathways. Most of these pathways are combinations of oxidation and reduction reactions, which occur at the same time. An oxidation reaction strips an electron from an atom in a compound, and the addition of this electron to another compound is a reduction reaction. Because oxidation and reduction usually occur together, these pairs of reactions are called redox reactions.
The removal of an electron from a molecule, results in a...
The removal of an electron from a molecule, results in a...
9.9K
Acid Halides to Ketones: Gilman Reagent
4.3K
Lithium dialkyl cuprate, also known as Gilman reagents, selectively reduces acid halides to ketones. The acid chloride is treated with Gilman reagent at −78 °C in the presence of ether solution to produce a ketone in good yield.
As shown below, the mechanism proceeds in two steps. First, one of the alkyl groups of the reagent acts as a nucleophile and attacks the acyl carbon of the acid chloride to form a tetrahedral intermediate. This is followed by the reformation of the carbon–oxygen...
As shown below, the mechanism proceeds in two steps. First, one of the alkyl groups of the reagent acts as a nucleophile and attacks the acyl carbon of the acid chloride to form a tetrahedral intermediate. This is followed by the reformation of the carbon–oxygen...
4.3K
Role of Reduced Coenzymes NADH and FADH₂
18.6K
The energy released from the breakdown of the chemical bonds within nutrients can be stored either through the reduction of electron carriers or in the bonds of adenosine triphosphate (ATP). In living systems, a small class of compounds functions as mobile electron carriers, molecules that bind to and shuttle high-energy electrons between compounds in pathways. The principal electron carriers that will be considered originate from the B vitamin group and are derivatives of nucleotides; they are...
18.6K


