通过先进的EPR表征来确定颗粒甲单氧化酶铜中心的价值和协调环境
Megen A Culpepper1, George E Cutsail, William A Gunderson
1Departments of ‡Molecular Biosciences and of §Chemistry, Northwestern University , Evanston, Illinois 60208, United States.
Journal of the American Chemical Society
|July 26, 2014
概括
颗粒甲单氧化酶 (pMMO) 使用铜中心氧化甲. 这项研究在二铜位点中确定了一个EPR活性铜离子,澄清了pMMO.
科学领域:
- 生物化学 生物化学
- 酶学 是一种酶学.
- 频谱学是一种光谱学.
背景情况:
- 颗粒甲单氧化酶 (pMMO) 在甲型细菌中对甲氧化至关重要.
- 它的铜中心是功能关键,但由于多个铜位点,使用EPR光谱来表征具有挑战性.
研究的目的:
- 使用光谱方法阐明 pMMO 中铜中心的作用和协调环境.
- 验证可溶性重组碎片 (spmoB) 作为研究pMMO的可靠模型.
主要方法:
- 电子偏磁共振 (EPR) 光谱学
- 电子核双共振 (ENDOR) 光谱学
- 电子旋转回声外调制 (ESEEM) 光谱学
- 分析金属含量分析的方法
- 在spmoB变体的位点定向突变发生.
主要成果:
- 来自spmoB的光谱数据与原生pMMO密切匹配,证实spmoB是一个有效的模型.
- 每个pMMO中确定了一个EPR活性Cu (II) 离子,位于二铜活性部位内,作为一个价值局部化的Cu (I) Cu (II) 对.
- 单铜工厂的地点被分配为Cu (I).
- 特定的histidine残留物 (His137/His139或His33/N-terminus) 参与了Cu (II) 协调.
- 没有发现与Cu (II) 离子结合的水体配体.
结论:
- 这项研究澄清了pMMO中的铜位点身份和协调.
- 它为未来对甲氧化机制的研究提供了一个验证的模型系统 (spmoB).
更多相关视频
11:04Ion Mobility-Mass Spectrometry Techniques for Determining the Structure and Mechanisms of Metal Ion Recognition and Redox Activity of Metal Binding Oligopeptides
Published on: September 7, 2019
8.3K
06:53Author Spotlight: Magnetometric Characterization of Intermediates in the Solid-State Electrochemistry of Redox-Active Metal-Organic Frameworks
Published on: June 9, 2023
2.5K
相关概念视频
03:02Colors and Magnetism
12.0K
Color in Coordination Complexes
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human...
When atoms or molecules absorb light at the proper frequency, their electrons are excited to higher-energy orbitals. For many main group atoms and molecules, the absorbed photons are in the ultraviolet range of the electromagnetic spectrum, which cannot be detected by the human eye. For coordination compounds, the energy difference between the d orbitals often allows photons in the visible range to be absorbed and emitted, which is seen as colors by the human...
12.0K
02:42Valence Bond Theory
8.9K
Coordination compounds and complexes exhibit different colors, geometries, and magnetic behavior, depending on the metal atom/ion and ligands from which they are composed. In an attempt to explain the bonding and structure of coordination complexes, Linus Pauling proposed the valence bond theory, or VBT, using the concepts of hybridization and the overlapping of the atomic orbitals. According to VBT, the central metal atom or ion (Lewis acid) hybridizes to provide empty orbitals of suitable...
8.9K
01:17Electron Paramagnetic Resonance (EPR) Spectroscopy: Organic Radicals
2.5K
Ideally, an unpaired electron shows a single peak in the EPR spectrum due to the transition between the two spin energy states. However, coupling interactions can occur between the spins of the unpaired electron and any neighboring spin-active nuclei. This hyperfine coupling results in hyperfine splitting, where the EPR signal is split into multiplets. The signals split into 2nI + 1 peaks, where n is the number of equivalent nuclei and I is the nuclear spin. These splitting patterns provide...
2.5K
02:51Metal-Ligand Bonds
19.2K
The hemoglobin in the blood, the chlorophyll in green plants, vitamin B-12, and the catalyst used in the manufacture of polyethylene all contain coordination compounds. Ions of the metals, especially the transition metals, are likely to form complexes.
In these complexes, transition metals form coordinate covalent bonds, a kind of Lewis acid-base interaction in which both of the electrons in the bond are contributed by a donor (Lewis base) to an electron acceptor (Lewis acid). The Lewis acid in...
In these complexes, transition metals form coordinate covalent bonds, a kind of Lewis acid-base interaction in which both of the electrons in the bond are contributed by a donor (Lewis base) to an electron acceptor (Lewis acid). The Lewis acid in...
19.2K
01:23Properties of Organometallic Compounds
2.0K
Organometallic compounds are compounds that contain a carbon–metal bond. Carbon belongs to an organyl group like alkyl, aryl, allyl, or benzyl groups. The metal can be from Group I or Group II of the periodic table, a transition metal, or a semimetal.
2.0K
01:27π Electron Effects on Chemical Shift: Overview
1.5K
An applied magnetic field causes loosely bound π-electrons in organic molecules to circulate, producing a local or induced diamagnetic field over a large spatial volume. As the molecules tumble in solution, the field generated by π-electrons in spherical substituents results in a zero net field. However, the net field generated by π-electrons in non-spherical substituents is not zero. The effect of this induced field depends on the orientation of the molecule with respect to B0,...
1.5K