15N R(1rho) サイト固有のNMRのリラクゼーション率によって研究された固体タンパク質のマイクロ秒の時間スケールの移動性
Alexey Krushelnitsky1, Tatiana Zinkevich, Detlef Reichert
1Kazan Institute of Biochemistry and Biophysics, Kazan, Russia. Krushelnitsky@mail.knc.ru
Journal of the American Chemical Society
|August 10, 2010
まとめ
研究者らは,固体タンパク質における窒素-15 R ((1rho) リラクゼーション率のサイト解析測定を達成した. この画期的な発見は,信頼性の高いマイクロ秒時間スケールのダイナミクス情報を提供しており,これはタンパク質の機能を理解する上で極めて重要です.
科学分野:
- バイオフィジックス 生物物理学
- 構造生物学 構造生物学とは
- 核磁共振 (NMR) スペクトロスコピー
背景:
- タンパク質のダイナミクスを理解することは,生物学的機能を解明するために極めて重要です.
- 核磁共振 (NMR) のリラクゼーション測定は,分子運動の洞察を提供します.
- タンパク質の動態を測定する以前の方法は,解像度と信頼性の面で限界がありました.
研究 の 目的:
- 固体タンパク質における窒素-15 R ((1rho) リラクゼーション率を測定するためのサイトで解決可能な方法を開発し,実証する.
- タンパク質サンプルからマイクロ秒のスケールで信頼性の高いダイナミック情報を抽出します.
- リラクゼーション速度測定に対する実験条件の影響を調査する.
主な方法:
- 活用された窒素-15 R(1rho) NMRのリラクゼーション速度測定.
- 鶏のアルファスペクトリンの15N,2H濃縮のマイクロクリスタリンSH3ドメインで,現場で解決された実験を行いました.
- 異なる温度とスピンロック周波数 (オン・オフ共振照射) で実験を行った.
主要な成果:
- 信頼性の高い (15) N R (((1rho) リラクゼーション率のサイト解析測定を成功裏に実証しました.
- R(1rho) に対するスピン・スピンの寄与は,低スピン・ロック・フィールドにおいてさえ,ペルデュテラートされたタンパク質では無視できるものであることを示した.
- 入手したR(1rho) 率を,内部タンパク質の移動性を特徴付けるために,既存のデータと比較した.
結論:
- 開発された方法は,マイクロ秒時間スケールのタンパク質ダイナミクスの信頼性の高い抽出を可能にします.
- この発見は,R ((1rho) 測定における干渉効果を最小限に抑えるために,ペルデュテレーションの利点を強調しています.
- このテクニックは,タンパク質の内部流動性の詳細な分析のための貴重なツールを提供します.
関連する概念動画
Atomic Nuclei: Types of Nuclear Relaxation
Nuclear relaxation restores the equilibrium population imbalance and can occur via spin–lattice or spin–spin mechanisms, which are first-order exponential decay processes.
In spin–lattice or longitudinal relaxation, the excited spins exchange energy with the surrounding lattice as they return to the lower energy level. Among several mechanisms that contribute to spin–lattice relaxation, magnetic dipolar interactions are significant. Here, the excited nucleus transfers energy to a nearby...
In spin–lattice or longitudinal relaxation, the excited spins exchange energy with the surrounding lattice as they return to the lower energy level. Among several mechanisms that contribute to spin–lattice relaxation, magnetic dipolar interactions are significant. Here, the excited nucleus transfers energy to a nearby...
¹H NMR of Conformationally Flexible Molecules: Temporal Resolution
At room temperature, the chair conformer of cyclohexane undergoes rapid ring flipping between two equivalent chair conformers at a rate of approximately 105 times per second. These two chair conformers are in equilibrium. The rapid ring flipping results in the interconversion of the axial proton to an equatorial proton and an equatorial to the axial proton. Such interconversions are too rapid and cannot be detected on the NMR timescale. Hence, the NMR spectrometer cannot distinguish between the...
¹H NMR of Labile Protons: Temporal Resolution
Protons bonded to heteroatoms such as nitrogen and oxygen exhibit a range of chemical shift values. This is due to the varying degree of hydrogen bonding between the proton and the heteroatom in other molecules. The extent of hydrogen bonding affects the electron density around the proton, thereby giving different chemical shift values for the protons in the proton NMR spectrum.
The –OH proton in alcohols typically appears in the range of δ 2 to 5 ppm but can vary depending on the specific...
The –OH proton in alcohols typically appears in the range of δ 2 to 5 ppm but can vary depending on the specific...
¹H NMR of Conformationally Flexible Molecules: Variable-Temperature NMR
The axial and equatorial protons in cyclohexane can be distinguished by performing a variable-temperature NMR experiment. In this process, except for one proton, the remaining eleven protons are replaced by deuterium. The deuterium substitution avoids the possible peak splitting caused by the spin-spin coupling between the adjacent protons. The remaining proton flips between the axial and equatorial positions.
NMR Spectrometers: Resolution and Error Correction
When magnetic nuclei in a sample achieve resonance and undergo relaxation, the signal detected in NMR is an approximately exponential free induction decay. Fourier transform of an exponential decay yields a Lorentzian peak in the frequency domain. Lorentzian peaks in an NMR spectrum are defined by their amplitude, full width at half maximum, and position, where the peak width is governed by the spin-spin relaxation time alone. In real experiments, however, the applied magnetic field is rendered...
2D NMR: Overview of Homonuclear Correlation Techniques
Homonuclear correlation spectroscopy (COSY) is a powerful technique used in Nuclear Magnetic Resonance (NMR) spectroscopy to study the correlations between nuclei of the same type within a molecule. It provides information about scalar couplings between adjacent nuclei, which helps determine connectivity and structural information. There are several COSY variants, each with its unique strengths and experimental parameters.
COSY90 is the standard two-dimensional (2D) COSY experiment that...
COSY90 is the standard two-dimensional (2D) COSY experiment that...

