在可溶性甲单氧酶中的分子间电子转移反应:歇斯底里在蛋白质功能中的作用
Jessica L Blazyk1, George T Gassner, Stephen J Lippard
1Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
Journal of the American Chemical Society
|December 8, 2005
概括
从降解的尼古丁胺胺二核酸 (NADH) 到可溶性甲单氧基酶基酶 (MMOH) 的电子转移对于甲转化至关重要. 辅助蛋白MMOB/MMOD抑制了这种电子转移,这表明形状变化是有效催化的关键.
科学领域:
- 生物化学 生物化学
- 生物物理化学 生物物理化学
- 酶动力学 酶动力学
背景情况:
- 溶性甲单氧化酶 (sMMO) 通过非血二铁中心将甲转化为甲醇.
- 从还原酶 (MMOR) 到基酶 (MMOH) 的电子转移为与二氧化物反应的sMMO.
- MMOR含有 [2Fe-2S] 和黄胺二核酸 (FAD) 假体组,可以促进电子转移.
研究的目的:
- 研究MMOR和MMOH之间的蛋白质间电子转移机制.
- 确定辅助蛋白MMOB和MMOD在调节电子转移速率中的作用.
- 阐明有效的甲单氧化所需的动力阶段和构造要求.
主要方法:
- 使用停止流量装置快速混合,以监测光学变化.
- 电子转移反应的动态分析.
- 辅助蛋白 (MMOB,MMOD) 对电子转移速率的研究影响.
主要成果:
- 从MMOR到MMOH的电子转移通过四个不同的动力相进行.
- 辅助蛋白MMOB和MMOD显著降低了电子传输吞吐量.
- MMOB/MMOD将电子转移到较慢的路径,表明抑制.
- 此外,MMOB/MMOD还抑制了从MMOR铁素类似物中转移电子的过程.
结论:
- 对于最大的电子转移速率,初始三元复合异构化是必要的.
- 提出了一个模型,其中MMOR诱导的MMOH形状变化在整个催化循环中持续存在.
- 多个相互转换的MMOH种群可能参与电子转移过程.
更多相关视频
11:25Targeting Cysteine Thiols for in Vitro Site-specific Glycosylation of Recombinant Proteins
Published on: October 4, 2017
09:37Combining Non-reducing SDS-PAGE Analysis and Chemical Crosslinking to Detect Multimeric Complexes Stabilized by Disulfide Linkages in Mammalian Cells in Culture
Published on: May 2, 2019
相关概念视频
Ligand Binding and Linkage
Allosteric proteins have more than one ligand binding site; the binding of a ligand to any of these sites influences the binding of ligands to the other sites. When a protein is allosteric, its binding sites are called coupled or linked. In the case of enzymes, the site that binds to the substrate is known as the active site and the other site is known as the regulatory site. When a ligand binds to the regulatory site, this leads to conformational changes in the protein that can influence the...
Mechanical Protein Functions
Proteins perform many mechanical functions in a cell. These proteins can be classified into two general categories- proteins that generate mechanical forces and proteins that are subjected to mechanical forces. Proteins providing mechanical support to the structure of the cell, such as keratin, are subjected to mechanical force, whereas proteins involved in cell movement and transport of molecules across cell membranes, such as an ion pump, are examples of generating mechanical force.
Structural Protein Function
Structural proteins are a category of proteins responsible for functions ranging from cell shape and movement to providing support to major structures such as bones, cartilage, hair, and muscles. This group includes proteins such as collagen, actin, myosin, and keratin.
Collagen, the most abundant protein in mammals, is found throughout the body. In connective tissue, such as skin, ligaments, and tendons, it provides tensile strength and elasticity. In bones and teeth, it mineralizes to form...
Collagen, the most abundant protein in mammals, is found throughout the body. In connective tissue, such as skin, ligaments, and tendons, it provides tensile strength and elasticity. In bones and teeth, it mineralizes to form...
Allosteric Proteins-ATCase
Binding sites linkages can regulate a protein's function. For example, enzyme activity is often regulated through a feedback mechanism where the end product of the biochemical process serves as an inhibitor.
Aspartate transcarbamoylase (ATCase) is a cytosolic enzyme that catalyzes the condensation of L-aspartate and carbamoyl phosphate to N-carbamoyl-L-aspartate. This reaction is the first step in pyrimidine biosynthesis. UTP and CTP, the end products of the pyrimidine synthesis pathway,...
Aspartate transcarbamoylase (ATCase) is a cytosolic enzyme that catalyzes the condensation of L-aspartate and carbamoyl phosphate to N-carbamoyl-L-aspartate. This reaction is the first step in pyrimidine biosynthesis. UTP and CTP, the end products of the pyrimidine synthesis pathway,...
Mechanical Protein Function
Proteins perform many mechanical functions in a cell. These proteins can be classified into two general categories- proteins that generate mechanical forces and proteins that are subjected to mechanical forces. Proteins providing mechanical support to the structure of the cell, such as keratin, are subjected to mechanical force, whereas proteins involved in cell movement and transport of molecules across cell membranes, such as an ion pump, are examples of generating mechanical force.
Structural Protein Function
Structural proteins are a category of proteins responsible for functions ranging from cell shape and movement to providing support to major structures such as bones, cartilage, hair, and muscles. This group includes proteins such as collagen, actin, myosin, and keratin.
Collagen, the most abundant protein in mammals, is found throughout the body. In connective tissue, such as skin, ligaments, and tendons, it provides tensile strength and elasticity. In bones and teeth, it mineralizes to form...
Collagen, the most abundant protein in mammals, is found throughout the body. In connective tissue, such as skin, ligaments, and tendons, it provides tensile strength and elasticity. In bones and teeth, it mineralizes to form...
