激进的SAM-依赖的碳插入到酶M集群中.
Jared A Wiig1, Yilin Hu1, Chi Chung Lee1
1Department of Molecular Biology & Biochemistry, University of California, Irvine 92697-3900.
概括
这是一种化酶酶.
科学领域:
- 生物化学 生物化学
- 酶学 是一种酶学.
- 生物有机化学 生物有机化学
背景情况:
- 酶催化生物固化,这是生命的关键过程.
- 酶的活性部位,M集群,含有独特的间歇性碳化物.
- 这种碳化物的起源和插入机制在很大程度上是未知的.
研究的目的:
- 为了阐明碳化物在化酶M集群中的起源.
- 为了确定负责碳化物插入的蛋白质.
- 为了比较碳插入机制与相关的激进SAM酶反应.
主要方法:
- 使用S-adenosylmethionine (SAM) 的放射性标记实验.
- 乳替代分析. 乳替代分析.
- 对组装蛋白NifB的作用进行分析.
主要成果:
- 在M集群中的碳化物起源于SAM的甲基组.
- 组装蛋白NifB负责将碳化物插入M集群.
- 该机制与激进SAM酶的RNA甲基化有相似之处.
结论:
- 化酶中的间歇性碳化物源自SAM,由NifB.插入.
- NifB的碳插入机制类似于参与RNA甲基化的激进SAM酶.
- 这项研究提供了对酶机制和间歇性碳化物的作用的初步见解.
相关概念视频
Radical Formation: Addition
Radicals can be formed by adding a radical to a spin-paired molecule. This is typically observed with unsaturated species, where the addition of a radical across the π bond leads to the production of a new radical by dissolving the π bond. For example, the addition of a Br radical to an alkene yields a carbon-centered radical.
Similar to charge conservation in chemical reactions, spin conservation is implicit for radical reactions. Accordingly, the product formed must possess an unpaired...
Similar to charge conservation in chemical reactions, spin conservation is implicit for radical reactions. Accordingly, the product formed must possess an unpaired...
Radical Formation: Overview
A bond can be broken either by heterolytic bond cleavage to form ions or homolytic bond cleavage to yield radicals. A fishhook arrow is used to represent the motion of a single electron in homolytic bond cleavage. There are two main sources from which radicals can be formed:
Radicals from spin-paired molecules:
Radicals can be obtained from spin-paired molecules either by homolysis or electron transfer. While two radicals are formed in the former, an electron is added in the latter, also known...
Radicals from spin-paired molecules:
Radicals can be obtained from spin-paired molecules either by homolysis or electron transfer. While two radicals are formed in the former, an electron is added in the latter, also known...
Radical Reactivity: Nucleophilic Radicals
Radicals adjacent to electron-donating groups are called nucleophilic radicals. These radicals readily react with electrophilic alkenes. The SOMO–LUMO interactions are the driving force for the reaction, where the high-energy SOMO of the electron-rich, nucleophilic radicals interacts with the low-energy LUMO of the electron-deficient, electrophilic alkenes. Such SOMO–LUMO interactions are the basis of reactive radical traps, affecting the selectivity in radical reactions. For instance, consider...
Radicals: Electronic Structure and Geometry
This lesson delves into the geometry of a radical, which is influenced by the electronic structure of the molecule. The principle is similar to that of a lone pair, where the unpaired electron influences the geometry at the radical center.
Accordingly, the structure of a trivalent radical lies between the geometries of carbocations and carbanions. An sp2-hybridized carbocation is trigonal planar, while an sp3-hybridized carbanion is trigonal pyramidal. Here, the difference in geometry is...
Accordingly, the structure of a trivalent radical lies between the geometries of carbocations and carbanions. An sp2-hybridized carbocation is trigonal planar, while an sp3-hybridized carbanion is trigonal pyramidal. Here, the difference in geometry is...
Radical Reactivity: Overview
Radicals, the highly reactive species, gain stability by undergoing three different reactions. The first reaction involves a radical-radical coupling, in which a radical combines with another radical, forming a spin‐paired molecule. The second reaction is between a radical and a spin‐paired molecule, generating a new radical and a new spin‐paired molecule. The third reaction is radical decomposition in a unimolecular reaction, forming a new radical and a spin‐paired molecule. These three...
Radical Reactivity: Intramolecular vs Intermolecular
Radical reactions can occur either intermolecularly or intramolecularly. In an intermolecular radical reaction, a nucleophilic radical adds to an electrophilic alkene or vice versa. In such reactions, the radical and generally the alkene, which is also called the radical trap, are two different molecules. Additionally, for such intermolecular reactions to occur, the radical trap must be active, present in an excess concentration, and the radical starting material must have a weak carbon–halogen...


