バクテリアホドプシンにおける陽子伝達の動態
1Center for Molecular Modeling, Center for Information Technology, National Institutes of Health, Bethesda, Maryland 20892, USA. leeys@mail.nih.gov
Journal of the American Chemical Society
|February 20, 2004
まとめ
バクテリアホドプシンにおけるプロトン伝達は,水路を通り,さらには水嫌悪性領域を通り,水路経由で発生する. この迅速で協調的な出来事は,Asp96からシフ基地への陽子の移動を容易にする.
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
- コンピューティング・ケミストリー
背景:
- バクテリアホドプシン (Bacteriorhodopsin) は,膜を横断するプロトンの輸送を容易にする.
- 陽子の移転はエネルギー伝導に不可欠です.
- 排水性チャネル経由の陽子伝達のメカニズムは不明である.
研究 の 目的:
- バクテリアホドプシンにおける部分的に水害性のチャンネルを通るプロトン伝達のメカニズムを調査する.
- 陽子の移転を促進する水分子の役割を明らかにする.
- Asp96からシフ基地への陽子移動のダイナミクスを理解するために.
主な方法:
- バクテリアホドプシンE204Q変異結晶構造を用いて,量子力学/分子力学 (QM/MM) モデルが構築されました.
- Ab initioダイナミクスシミュレーションは,CHARMM/GAMESSの方法論を用いて行われました.
- 主要な残留物 (Asp96,Asp85,Thr89) と網膜染色体は量子力学的に処理されました.
主要な成果:
- Asp96とM州のシフ基地の間に水路が形成されています.
- 陽子伝達は,水連鎖が確立されると,高速 (<1 ps),協調的なイベントとして発生します.
- 陽子転送は,Asp85.5の陽子化状態から独立しています.
- 転送は,Asp96から最も近い水分子へのプロトン提供によって開始されます.
結論:
- 水分子は,バクテリアホドプシン (bacteriorhodopsin) の排水性領域を通過するプロトン移動を媒介するために不可欠です.
- 協調した,急速な陽子転送機構は,構造化された水鎖によって促進されます.
- この研究は,生物学的システムにおける陽子伝送ダイナミクスに関する洞察を提供します.
関連する概念動画
01:32The Retina
The retina is a layer of nervous tissue at the back of the eye that transduces light into neural signals. This process, called phototransduction, is carried out by rod and cone photoreceptor cells in the back of the retina.
01:37Energy to Drive Translocation
Mitochondrial protein import is powered by two distinct energy sources: ATP hydrolysis and electrochemical potential across the inner membrane. Newly synthesized precursors are bound by cytosolic chaperones of the Hsp70 family, which guide them to the import receptors on the mitochondrial surface. Utilizing the energy of ATP hydrolysis, Hsp70 chaperones transfer these precursors to the TOM receptors on the mitochondrial outer membrane.
Generally, polypeptides are unfolded by two distinct...
Generally, polypeptides are unfolded by two distinct...
01:05Mechanism of Ciliary Motion
The ciliary structures were first seen in 1647 by Antonie Leeuwenhoek while observing the protozoans. In lower organisms, these appendages are responsible for cell movement, while in higher organisms, these appendages help in the movement of the extracellular fluids within the body cavities.
The cilia are made up of microtubules in a 9+2 arrangement, with nine microtubule doublet ring bundles, surrounding a pair of central singlet microtubule bundles. The doublet microtubule bundles are...
The cilia are made up of microtubules in a 9+2 arrangement, with nine microtubule doublet ring bundles, surrounding a pair of central singlet microtubule bundles. The doublet microtubule bundles are...
01:21G-Protein Gated Ion Channels
GPCRs are primarily responsible for our sense of smell, taste, and vision. The binding of a sensory stimulus activates GPCR to stimulate effector proteins, many of which are ion channels in the sensory organs. GPCRs modulate the opening and closing of the target ion channels either directly by binding them, or by releasing second messengers that activate these channels. As ions move across the membrane, the membrane potential is altered, which induces an appropriate response.
Sensory organs,...
Sensory organs,...
01:05Mechanism of Ciliary Motion
The ciliary structures were first seen in 1647 by Antonie Leeuwenhoek while observing the protozoans. In lower organisms, these appendages are responsible for cell movement, while in higher organisms, these appendages help in the movement of the extracellular fluids within the body cavities.
The cilia are made up of microtubules in a 9+2 arrangement, with nine microtubule doublet ring bundles, surrounding a pair of central singlet microtubule bundles. The doublet microtubule bundles are...
The cilia are made up of microtubules in a 9+2 arrangement, with nine microtubule doublet ring bundles, surrounding a pair of central singlet microtubule bundles. The doublet microtubule bundles are...
01:22Photoreceptors and Visual Pathways
At the molecular level, visual signals trigger transformations in photopigment molecules, resulting in changes in the photoreceptor cell's membrane potential. The photon's energy level is denoted by its wavelength, with each specific wavelength of visible light associated with a distinct color. The spectral range of visible light, classified as electromagnetic radiation, spans from 380 to 720 nm. Electromagnetic radiation wavelengths exceeding 720 nm fall under the infrared category, whereas...