通过固态NMR直接检测离子通道选择性过器中的绑定离子
Carl Öster1, Kumar Tekwani Movellan2, Benjamin Goold3,4
1Department of Molecular Biophysics, Leibniz-Forschungsinstitut für Molekulare Pharmakologie, Robert-Rössle-Str. 10, 13125 Berlin, Germany.
Journal of the American Chemical Society
|February 24, 2022
概括
固态NMR检测离子通道中的氨离子,模仿. 不同的离子通道结构揭示了不同的离子结合点和水相互作用,澄清了离子导电机制.
科学领域:
- 生物物理学的生物物理.
- 结构生物学 结构生物学
- 分子生物物理学 分子生物物理学
背景情况:
- 离子通道对于细胞功能至关重要,促进了通过膜的离子运输.
- 了解选择性过器内的离子相互作用至关重要但具有挑战性,尽管有可用的结构数据.
研究的目的:
- 使用固态NMR与15N标记的离子作为离子模拟器来探测离子结合点.
- 研究非选择性 (NaK) 和选择性 (NaK2K,KcsA-Kv1.3) 离子通道中的离子-水相互作用和导电机制.
主要方法:
- 固态核磁共振 (NMR) 谱学使用15N标记的离子.
- 磁化转移实验以确定离子结合点和与通道组件和水的相互作用.
- 分子动力学模拟以补充实验发现和探索离子行为.
主要成果:
- 在NaK (两个峰) 和NaK2K (四个峰) 中观察到明显的氨离子信号,与它们已知的离子结合点相对应.
- 磁化转移揭示了特定的离子-水接触,支持NaK2K的直接敲击机制.
- 在NaK2K和KcsA-Kv1.3之间发现了结合离子化学转移的显著差异,尽管它们的序列和结构相似.
结论:
- 固态NMR有效地可视化了离子通道内的离子结合点和相互作用.
- 该研究提供了对离子导电机制的见解,特别是水在选择性中的作用.
- 突出了结构相似的通道内的离子环境的差异,表明了影响离子行为的微妙因素.
相关概念视频
NMR Spectroscopy Of Amines
9.5K
In proton NMR spectroscopy, primary amines and secondary amines showcase their N–H protons as a broad signal in the chemical shift range between δ 0.5 and 5 ppm. The exact position in this range depends on several factors, including sample concentration, hydrogen bonding, and the type of solvent used. Since amine protons undergo fast proton exchange in solution, the protons are labile and therefore do not participate in any splitting with adjacent protons. Thus, the observed peak is...
9.5K
Mass Spectrometry of Amines
4.6K
In mass spectroscopy, amines undergo fragmentation to give parent ions with odd molecule weights. This observed mass spectrum follows the nitrogen rule: a molecule with an odd number of nitrogen atoms produces a parent ion with an odd molecular weight. The remaining fragments have an even mass.
Amines undergo fragmentation through α cleavage, producing nitrogen-containing cations—iminium ions—and alkyl radicals. Mass spectra of aromatic and cyclic aliphatic amines exhibit...
Amines undergo fragmentation through α cleavage, producing nitrogen-containing cations—iminium ions—and alkyl radicals. Mass spectra of aromatic and cyclic aliphatic amines exhibit...
4.6K
Chemical Shift: Internal References and Solvent Effects
878
In an NMR sample, precise measurement of the absolute absorption frequencies of nuclei is difficult. A standard internal reference compound is added, and the frequency difference between the reference signal and sample signals is measured.
The internal reference compound generally used in NMR spectroscopy is tetramethylsilane (TMS). TMS is preferred because it is chemically inert, soluble in NMR solvents, and easily removable. Also, the highly shielded methyl protons in TMS yield an intense...
The internal reference compound generally used in NMR spectroscopy is tetramethylsilane (TMS). TMS is preferred because it is chemically inert, soluble in NMR solvents, and easily removable. Also, the highly shielded methyl protons in TMS yield an intense...
878
Insensitive Nuclei Enhanced by Polarization Transfer (INEPT)
571
Insensitive Nuclei Enhanced by Polarization Transfer (INEPT) is an advanced Nuclear Magnetic Resonance (NMR) technique specifically designed to detect and enhance the signals of low-abundance nuclei, such as carbon-13 and nitrogen-15, in small molecules. The fundamental principle behind INEPT is the transfer of polarization from a more abundant and highly polarizable nucleus, typically hydrogen-1, to the low-abundance nucleus of interest. This process effectively boosts the NMR signal of the...
571
High-Performance Liquid Chromatography: Types of Detectors
871
The role of the detectors in High-Performance Liquid Chromatography (HPLC) is to analyze the solutes as they exit from the chromatographic column. The detector recognizes the solute's property and generates corresponding electrical signals, which are converted into a readable graph of the detector's response versus elution time called a chromatogram at the computer. There are several types of HPLC detectors, each with its own advantages and limitations, depending on the analyte...
871
Mass Spectrometry: Amine Fragmentation
1.8K
Amines can be identified using mass spectroscopy based on their characteristic fragmentation patterns. The molecular ions of amines undergo fragmentation via ⍺-cleavage. The ⍺-cleavage of the carbon-carbon bonds in amines generates an alkyl radical and resonance-stabilized nitrogen-containing cation.
In amines, the number of nitrogen atoms affects the mass of the molecular ion, which is described by the nitrogen rule of mass spectrometry. This rule states that a compound containing...
In amines, the number of nitrogen atoms affects the mass of the molecular ion, which is described by the nitrogen rule of mass spectrometry. This rule states that a compound containing...
1.8K


