对二甲基硫氧化减少酶催化中间体的光谱和电子结构研究:对电子和原子转移活性的影响
Regina P Mtei1, Ganna Lyashenko, Benjamin Stein
1Department of Chemistry and Chemical Biology, The University of New Mexico, MSC03 2060, 1 University of New Mexico, Albuquerque, New Mexico 87131-0001, USA.
Journal of the American Chemical Society
|June 9, 2011
概括
研究人员使用EPR,电子吸收和MCD光谱仪研究了二甲基硫氧化还原酶 (DMSOR) 中的偏磁性des-oxoMo(V) 中间体的电子结构. 结果揭示了它的低对称几何和金属中心轨道,对酶功能至关重要.
科学领域:
- 生物化学 生物化学
- 生物有机化学 生物有机化学
- 频谱学是一种光谱学.
背景情况:
- 甲基二硫酸减少酶 (DMSOR) 是生物氧化还原过程中的关键酶.
- 了解催化中间体对于阐明酶机制至关重要.
- 偏磁性复合体在各种酶反应中起着至关重要的作用.
研究的目的:
- 描述DMSOR中真正的偏磁性脱氧Mo(V) 中间体的电子结构.
- 为了确定这个中间体的协调几何和金属-合物结合.
- 为了将中间体的电子特性与酶稳定性和电子转移相关联.
主要方法:
- 电子偏磁共振 (EPR) 光谱学.电子偏磁共振 (EPR) 光谱学.
- 电子吸收光谱学. 电子吸收光谱学.
- 磁圆二元化 (MCD) 光谱法.磁圆二元化 (MCD) 光谱法.
- 量子化学电子结构计算.
主要成果:
- EPR揭示了体g-和A-张量,表明了低对称度的几何结构.
- 确定了一个单独占用的分子轨道,主要以金属为中心.
- 光谱数据和计算提供了MCD和吸收频段的完整分配.
- 获得了对金属-合物结合,MoV协调和MoV-S共价性的详细理解.
结论:
- 该研究阐明了Mo(V) 介质的电子结构和几何结构.
- 这些发现提供了关于DMSOR中中间体和电子转移再生的稳定性的见解.
- 在DMSOR酶家族的反应坐标的背景下,讨论了des-oxo Mo(V) 和des-oxo Mo(IV) 结构之间的关系.
相关概念视频
Preparation and Reactions of Sulfides
Sulfides are the sulfur analog of ethers, just as thiols are the sulfur analog of alcohol. Like ethers, sulfides also consist of two hydrocarbon groups bonded to the central sulfur atom. Depending upon the type of groups present, sulfides can be symmetrical or asymmetrical. Symmetrical sulfides can be prepared via an SN2 reaction between 2 equivalents of an alkyl halide and one equivalent of sodium sulfide.
Oxymercuration-Reduction of Alkenes
Oxymercuration–reduction of alkenes is one of the major reactions converting alkenes to alcohols. It involves the hydration of alkenes with mercuric acetate in a mixture of tetrahydrofuran and water, forming an organomercury adduct. This is followed by a demercuration step in which the adduct is reduced to an alcohol using sodium borohydride.
Preparation and Reactions of Thiols
Thiols are prepared using the hydrosulfide anion as a nucleophile in a nucleophilic substitution reaction with alkyl halides. For instance, bromobutane reacts with sodium hydrosulfide to give butanethiol.
Reactions at the Benzylic Position: Oxidation and Reduction
The benzylic position describes the position of a carbon atom attached directly to a benzene ring. Benzene by itself does not undergo oxidation. In contrast, the benzylic carbon is quite reactive in the presence of strong oxidizing agents such as KMnO4 or H2CrO4. Therefore, alkylbenzenes are readily oxidized to benzoic acid, irrespective of the type of alkyl groups.
Phase I Reactions: Reductive Reactions
Phase I biotransformation reductive reactions are chemical processes that modify drugs by introducing or revealing polar functional groups via reduction. Enzymes called reductases catalyze these reactions, playing a pivotal role in drug metabolism by transforming lipophilic drugs into more polar, water-soluble metabolites for easy excretion. An essential type of reductive reaction is the carbonyl group reduction, where aldehydes and ketones are reduced to alcohols. An example is the...
Oxidation of Alkenes: Syn Dihydroxylation with Osmium Tetraoxide
Alkenes are converted to 1,2-diols or glycols through a process called dihydroxylation. It involves the addition of two hydroxyl groups across the double bond with two different stereochemical approaches, namely anti and syn. Dihydroxylation using osmium tetroxide progresses with syn stereochemistry.

![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)
