Pressure effects on the photocycle of purple membrane.
Pressure effects on the photocycle of purple membrane.
复制标题
压力对紫色膜光循环的影响。
DOI：
10.1021/bi00318a027
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发表时间：
1984
期刊：
影响因子：
2.9
通讯作者：
Eisenstein,L
中科院分区：
文献类型：
--
作者：
Marque,J;Eisenstein,L
摘要：我们研究了静水压力对盐生盐杆菌紫膜光循环动力学的影响。这些数据被解释在一个单向和无分支的模型。我们发现，光循环的所有不同过程都受到压力的阻碍，早期的快速过程对压力的敏感性低于晚期的缓慢过程。这些结果与溶剂粘度对光循环动力学的影响的定性相似性表明，压力对光循环动力学的主要影响是通过在盐生盐杆菌细胞膜中发现的光驱动质子泵的特性粘度。紫膜含有单一蛋白质，细菌视紫红质（bR）。1 bR中的发色团是通过质子化Schiff碱键与赖氨酸残基（Lys-216）共价结合的视黄醛分子。紫色膜通过吸收可见辐射并利用能量将质子从细菌细胞内部泵送到外部来发挥作用，从而产生跨膜电化学梯度。该细菌能够将细胞膜上其他地方的梯度松弛与S '-二磷酸腺苷的磷酸化结合起来。紫色膜因此使细菌能够在缺氧的情况下产生三磷酸腺苷（ATP），从而在厌氧环境中生存。与质子穿过紫膜的运动有关的是紫膜中复杂的颜色变化。这些颜色变化统称为紫膜光循环或细菌视紫红质光循环（Lozier等人，1975年）。光循环不是一个定义明确的概念;不同的工作者对中间体的数量和这些中间体之间的反应有不同的看法。在文献中，人们发现光循环的整个唯象模型，从简单的顺序模型，bR*~·-*·
Jeffrey Marque and Laura Eisenstein* abstract: We studied the effects of hydrostatic pressure on the kinetics of the photocycle of purple membrane from Halobacterium halobium. The data were interpreted in terms of a unidirectional and unbranched model. We found that all of the distinct processes of the photocycle are retarded by pressure, with the earlier, fast processes showing less sensitivity to pressure than thelater, slow processes. Thequalitative similarity of these results with the effects of solvent viscosity on the photocycle kinetics suggests that the primary effects of pressure on the kinetics are via the intrinsic viscosity of theJRirple membrane is the light-driven proton pump found in the cell membrane of Halobacterium halobium. Purple membrane contains a single protein, bacteriorhodopsin (bR). 1 The chromophore in bR is a molecule of retinal covalently bound to a lysine residue (Lys-216) via a protonated Schiff base linkage. Purple membrane functions by absorbing visible radiation and using the energy to pump protons from the inside to the outside of the bacterial cell, thus generating a transmembrane electrochemical gradient. The bacterium is able to couple the relaxation of the gradient, elsewhere on the cell membrane, to the phosphorylation of adenosine S'-diphosphate. Purple membrane thus enables thebacterium to generate adenosine S'-triphosphate (ATP) in the absence of oxygen and thereby survive in anaerobic environments. Associated with the movement of protons across the purple membrane are complicated color changes in the purple mem-brane. These color changes are collectively referred to as the purple membrane photocycle, or bacteriorhodopsin photocycle (Lozier et al., 1975). The photocycle is not a well-defined concept; different workers have different opinions as to the number of intermediates and to the reactions between those intermediates. In the literature, one finds an entire gamut of phenomenological models for thephotocycle, from the simple sequential model, bR*~·-*·