低温タンパク質ダイナミクス:タンパク質間の振動と150kでのボゾンピークのシミュレーション分析
Vandana Kurkal-Siebert1, Jeremy C Smith
1Interdisciplinary Center for Scientific Computing (IWR), University of Heidelberg, Im Neuenheimer Feld 368, D-69120 Heidelberg, Germany. vandana.kurkal@iwr.uni-heidelberg.de
Journal of the American Chemical Society
|February 16, 2006
まとめ
タンパク質のエネルギー景観と相互作用を理解するために不可欠な低周波タンパク質の振動は,分子ダイナミクスシミュレーションを使用して研究されました. ボゾンピークは,集団的調和振動から発生し,タンパク質間の振動は,タンパク質とタンパク質の相互作用の洞察を提供します.
科学分野:
- バイオフィジックス 生物物理学
- コンピュータ生物学 コンピュータ生物学
- タンパク質のダイナミクス
背景:
- 低周波タンパク質の低温のダイナミクスを理解することは,機能性タンパク質のエネルギー景観を特徴づけるための鍵です.
- タンパク質ガラス変異の起源とタンパク質とタンパク質の相互作用を調査するには,集団タンパク質の動きの詳細な分析が必要です.
- 低温ダイナミクスは,タンパク質の行動と機能の基本的な側面についての洞察を提供します.
研究 の 目的:
- 150 Kの結晶型ミオグロビンにおけるイントラおよびインタータンパク質の振動を特徴づけること.
- ダイナミック構造因子におけるボソンピークの起源を解明する.
- 集団的振動とタンパク質対タンパク質の相互作用の関係を探求する.
主な方法:
- 150 Kの結晶型ミオグルビンモデルの分子動力学 (MD) シミュレーション.
- 振動モードを特定するための正常モード分析.
- 集団運動を分析するためのMD軌道の主な構成要素分析 (PCA)
- 動的構造因子の計算. 動的構造因子.
主要な成果:
- ボゾンピーク (2-2.5 meV) は,約10^2の集合的,調和的振動から発生する.
- 実験的なボソンピークを再現するには,正確な環境記述が不可欠です.
- 動的構造因子におけるより低いエネルギーピークは,タンパク質間の調和振動に対応する.
- これらのタンパク質間の振動は,タンパク質とタンパク質の相互作用に関する洞察を提供します.
結論:
- 集合的調和振動は,ミオグロビンのボゾンピークの原因である.
- タンパク質間振動は,タンパク質とタンパク質の相互作用の物理的な性質に関する貴重な情報を提供します.
- タンパク質環境の正確なモデリングは,低周波のダイナミクスをシミュレートするために重要です.
関連する概念動画
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...
Atomic Nuclei: Nuclear Spin State Population Distribution
Near absolute zero temperatures, in the presence of a magnetic field, the majority of nuclei prefer the lower energy spin-up state to the higher energy spin-down state. As temperatures increase, the energy from thermal collisions distributes the spins more equally between the two states. The Boltzmann distribution equation gives the ratio of the number of spins predicted in the spin −½ (N−) and spin +½ (N+) states.
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.
IR Spectroscopy: Hooke's Law Approximation of Molecular Vibration
A covalently bonded heteronuclear diatomic molecule can be modeled as two vibrating masses connected by a spring. The vibrational frequency of the bond can be expressed using an equation derived from Hooke's law, which describes how the force applied to stretch or compress a spring is proportional to the displacement of the spring. In this case, the atoms behave like masses, and the bond acts like a spring.
According to Hooke's law, the vibrational frequency is directly proportional to the...
According to Hooke's law, the vibrational frequency is directly proportional to the...
Protein Dynamics in Living Cells
Different fluorescence-based techniques are used to study the protein dynamics in living cells. These techniques include FRAP, FRET, and PET.
Fluorescent recovery after photobleaching (FRAP) is a fluorescent-protein-based detection technique used to quantify protein movement rates within the cell. This method exposes a small portion of the cell to an intense laser beam. The laser beam causes permanent photobleaching of the fluorophore-tagged proteins in the exposed region. As the bleached...
Fluorescent recovery after photobleaching (FRAP) is a fluorescent-protein-based detection technique used to quantify protein movement rates within the cell. This method exposes a small portion of the cell to an intense laser beam. The laser beam causes permanent photobleaching of the fluorophore-tagged proteins in the exposed region. As the bleached...
Atomic Spectroscopy: Effects of Temperature
Atomization, converting samples into gas-phase atoms and ions, is essential for atomic spectroscopy. The flame temperature required for atomization affects the efficiency of the atomic spectroscopic methods by increasing the atomization efficiency and the relative population of the excited and ground states.
At thermal equilibrium, the relative populations of excited and ground state atoms can be estimated using the Maxwell–Boltzmann distribution. For example, an increase in temperature from...
At thermal equilibrium, the relative populations of excited and ground state atoms can be estimated using the Maxwell–Boltzmann distribution. For example, an increase in temperature from...


