一个pH敏感的,多彩的,化兰胺的偏磁性NMR探针
Wei-Min Liu1, Peter H J Keizers, Mathias A S Hass
1Gorlaeus Laboratories, Leiden Institute of Chemistry, Leiden University, 2300 RA Leiden, The Netherlands.
Journal of the American Chemical Society
|September 22, 2012
概括
一个新的兰化NMR探头,Caged Lanthanide NMR Probe-7 (CLaNP-7),提供了增强的蛋白质结构分析. 它的低电荷和依赖pH值的磁性特性为宏分子特征提供了新的见解.
科学领域:
- 生物物理化学 生物物理化学
- 结构生物学 结构生物学
- 核磁共振 (NMR) 光谱学 核磁共振 (NMR) 光谱学
背景情况:
- 超磁性兰坦化离子是NMR光谱学的关键工具,用于描述宏分子结构和动力学.
- 现有的兰化核磁共振探头在电荷和磁性特性上有局限性.
研究的目的:
- 为了引入一种新的化兰酸核磁共振探针,Caged Lanthanide NMR Probe-7 (CLaNP-7).
- 评估CLaNP-7在蛋白质结构确定中的实用性,并与以前的探测器相比探索其独特的特性.
主要方法:
- 对CLaNP-7探测器的开发和描述.
- 通过二硫化物桥梁将CLaNP-7连接到蛋白质表面.
- 核磁共振光谱分析探头对光谱参数和结构约束的影响.
- 对依赖pH的磁感应力张量定向的研究.
主要成果:
- CLaNP-7是一种刚性,黄色的探头,比CLaNP-5 (+3) 具有较低的正电荷 (+1),从而最大限度地降低了表面电位变化.
- 探测器提供了一个独特的磁感应力张量,使每个工程氨酸对能够实现双重结构约束.
- 观察到磁感应张量 (pK(a) ≈ 7) 的pH依赖性方向,与histidine相互作用相关.
结论:
- CLaNP-7扩大了基于兰他尼德的NMR探针用于宏分子研究的适用性.
- 依赖pH的与histidine残留物的相互作用为探测当地的蛋白质环境提供了新的途径.
- 这种探测器有助于对蛋白质进行先进的结构和动态表征.
相关概念视频
Labeling DNA Probes
DNA probes are fragments of DNA labeled with a reporter tag to enable their detection or purification. The resulting labeled DNA probes can then hybridize to target nucleic acid sequences through complementary base-pairing, and may be used to recover or identify these regions.
Radioisotopes, fluorophores, or small molecule binding partners like biotin or digoxigenin, are the most widely used reporter tags for labeling DNA probes. These labels can be attached to the probe DNA molecule via...
Radioisotopes, fluorophores, or small molecule binding partners like biotin or digoxigenin, are the most widely used reporter tags for labeling DNA probes. These labels can be attached to the probe DNA molecule via...
Insensitive Nuclei Enhanced by Polarization Transfer (INEPT)
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...
¹³C NMR: Distortionless Enhancement by Polarization Transfer (DEPT)
When proton-coupled carbon-13 spectra are simplified by a broadband proton decoupling technique, structural information about the coupled protons is lost. Distortionless enhancement by polarization transfer (DEPT) is a technique that provides information on the number of hydrogens attached to each carbon in a molecule. While the DEPT experiment utilizes complex pulse sequences, the pulse delay and flip angle are specifically manipulated. The resulting signals have different phases depending on...
Other Nuclides: 31P, 19F, 15N NMR
Many organic, inorganic, and biological molecules contain spin-half nuclei such as nitrogen-15, fluorine-19, and phosphorus-31. As a result, NMR studies of these nuclei have found extensive applications in chemical and biological research.
While fluorine-19 and phosphorous-31 have high natural abundances (100%) and positive gyromagnetic ratios, nitrogen-15 has a low natural abundance and a negative gyromagnetic ratio. However, nitrogen-15 is still preferred over nitrogen-14 (which has a high...
While fluorine-19 and phosphorous-31 have high natural abundances (100%) and positive gyromagnetic ratios, nitrogen-15 has a low natural abundance and a negative gyromagnetic ratio. However, nitrogen-15 is still preferred over nitrogen-14 (which has a high...
NMR Spectroscopy: Chemical Shift Overview
The position of the absorption signal of a sample is reported relative to the position of the signal of tetramethylsilane (TMS), which is added as an internal reference while recording spectra. The difference between the absorption frequencies of the sample and TMS (in Hz) is divided by the spectrometer operating frequency (in MHz) to obtain a dimensionless quantity called the chemical shift. It is reported on the δ (delta) scale and expressed in parts per million.
For instance, the proton...
For instance, the proton...
Proton (¹H) NMR: Chemical Shift
Organic molecules primarily contain carbon and hydrogen atoms. While all the hydrogen isotopes are NMR-active, protium or hydrogen-1 is the most abundant. It has a significant energy separation between its nuclear spin states due to its large gyromagnetic ratio. As per Boltzmann's distribution, an increase in the energy separation implies a greater excess population of nuclei available for excitation, resulting in a strong NMR absorption signal.
Absorption signals of all the protium nuclei in a...
Absorption signals of all the protium nuclei in a...


