水の大きさと分子起源は,タンパク質の隣で減速する
Fabio Sterpone1, Guillaume Stirnemann, Damien Laage
1Department of Chemistry, Ecole Normale Supérieure, UMR ENS-CNRS-UPMC 8640, 24 rue Lhomond, 75005 Paris, France. fabio.sterpone@ibpc.fr
Journal of the American Chemical Society
|February 17, 2012
まとめ
タンパク質の水分化シェルダイナミクスは,水の動きを遅らせます. 重要な要因は,タンパク質の幾何学と水-タンパク質の水素結合であり,タンパク質の近くの水の動態を説明します.
科学分野:
- バイオフィジックス 生物物理学
- 物理化学 物理化学
- コンピュータ生物学 コンピュータ生物学
背景:
- 水分化殻のダイナミクスは,タンパク質の折りたたみと機能に不可欠です.
- タンパク質の近くの水の動態は,散布水よりも遅いですが,正確な原因は議論されています.
研究 の 目的:
- タンパク質の水分化ダイナミクスの分子説明を提供するために.
- 水のダイナミクスを支配する主要なタンパク質の特徴を特定する.
- 観察された水分子の減速を定量的に説明する.
主な方法:
- モデルタンパク質 (ライソ酵素) の周りの水動力の数値シミュレーション.
- 拡張ジャンプモデルを用いた理論モデリング.
- 水の方向転換と水素結合 (HB) ダイナミクスの顕微鏡によるマッピング.
主要な成果:
- 給水層の水の80%は2〜3倍の減速を示し,残りの部分は,NMRデータと一致する力法則の行動を示しています.
- タンパク質界面での水の方向転換は,大量の水と同じような大きな角のジャンプによって支配されています.
- 理論モデルでは,トポロジカル・エクスルード・ボリュームと水タンパク質のHB強度が減速の重要な要因として特定されました.
結論:
- タンパク質の幾何学とHB強度は,水分化殻の動態を定量的に説明する.
- 拡張ジャンプモデルは,タンパク質近くの水の減速を理解するための厳格な枠組みを提供します.
- これらの発見は,タンパク質の折りたたみ,機能,水との相互作用についての洞察を提供します.
関連する概念動画
01:25Aquaporins
Aquaporins or AQPs are a family of integral membrane proteins whose primary function is to transport water, while some called aquaglyceroporins also transport glycerol. In addition, aquaporins have also been suspected to be involved in transporting volatile substances, such as carbon dioxide and ammonia, across membranes. Such AQPs that act as gas channels are often highly expressed in cells involved in the gaseous exchange, such as red blood cells, epithelial cells, and pulmonary capillaries.
01:24Protein Diffusion in the Membrane
Proteins show rotational as well as lateral diffusion across the membrane. The lateral diffusion of proteins was confirmed through the cell fusion experiment where mouse and human cells were fused, resulting in hybrid cells. When the human and mouse cells fused, the specific membrane proteins on human and mouse cells were marked with the red and green-fluorescent markers, respectively. Initially, the red and green fluorescence was located on the respective hemisphere of the cell. As time...
01:26Regulation of Water Output
The human body predominantly expels water through the urinary system. On average, an individual generates around 1.5 liters of urine each day. This amount can fluctuate based on how well a person is hydrated, but a critical minimum quantity of urine must be produced to ensure the body's proper functioning. Daily, the kidneys remove 600 to 1200 milliosmoles of dissolved substances, effectively excreting excess minerals and water-soluble toxins such as creatinine, urea, and uric acid from the...
01:27Distribution of Molecular Speeds
The motion of molecules in a gas is random in magnitude and direction for individual molecules, but a gas of many molecules has a predictable distribution of molecular speeds. This predictable distribution of molecular speeds is known as the Maxwell-Boltzmann distribution. The distribution of molecular speeds in liquids is comparable to that of gases but not identical and can help to understand the phenomenon of the boiling and vapor pressure of a liquid. Consider that a molecule requires a...