质子转移的动力学在背后的hodopsin
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
概括
质子转移发生在bacteriorhodopsin通过水通道,甚至通过疏水区域. 这种快速,协调的事件促进了质子从Asp96到希夫基地的移动.
科学领域:
- 生物物理学的生物物理.
- 结构生物学 结构生物学
- 计算化学的计算化学
背景情况:
- 细菌体多普辛促进了通过膜的质子运输.
- 质子转移对于能量传导至关重要.
- 通过疏水性通道进行质子转移的机制尚不清楚.
研究的目的:
- 为了研究通过bacteriorhodopsin中的部分疏水通道进行质子转移的机制.
- 阐明水分子在促进质子转移中的作用.
- 了解从Asp96到希夫基地的质子转移动态.
主要方法:
- 一个量子力学/分子力学 (QM/MM) 模型是使用bacteriorhodopsin E204Q突变晶体结构构建的.
- 最初的动力学模拟使用CHARMM/GAMESS方法进行.
- 关键残留物 (Asp96,Asp85,Thr89) 和视网膜染色体被量子力学处理.
主要成果:
- 在Asp96和M州的希夫基地之间形成了一条水道.
- 一旦建立了水链,质子转移以快速 (<1 ps) 的形式发生,这是一个协调的事件.
- 质子转移独立于Asp85.5的质子化状态.
- 转移是通过从Asp96到最近的水分子的质子捐赠启动的.
结论:
- 水分子对于中介质子转移通过bacteriorhodopsin的疏水性区域至关重要.
- 一个协调的,快速的质子转移机制是由结构化的水链促进的.
- 这项研究提供了对生物系统中质子转移动态的见解.
相关概念视频
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...