Photobleaching of Bacteriorhodopsin Solubilized with Triton X-100
Photobleaching of Bacteriorhodopsin Solubilized with Triton X-100
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DOI：
10.1562/2005-03-22-ra-470
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发表时间：
2005-09
期刊：
影响因子：
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通讯作者：
Takanori Sasaki;M. Sonoyama;M. Demura;S. Mitaku
中科院分区：
文献类型：
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作者：
Takanori Sasaki;M. Sonoyama;M. Demura;S. Mitaku
摘要在目前的研究中，我们研究了与脂膜形成六边形晶格对天然细菌视紫红质（bR）结构稳定性的影响。在黑暗中和可见光照射下，用温和的非离子去污剂Triton X-100（TX 100）溶解bR进行变性动力学测量。溶解的bR在黑暗中在TX 100的宽浓度范围内（1至200 mM）是稳定的。在紫色膜中，由于相邻发色团之间的相互作用，在可见圆二色光谱中观察到双叶带。在所有浓度的TX 100下，这被单个阳性条带取代。在用可见光照射时，TX 100溶解的bR清楚地显示出对细菌视蛋白的光漂白。这些实验结果表明，光漂白是由于紫膜晶格内缺乏分子间的相互作用。广泛的动力学测量进一步表明，光漂白的速率常数是强烈依赖于洗涤剂的浓度，虽然光漂白的活化能不显着改变与TX 100的浓度。光漂白的增溶bR的机制进行了讨论相对于洗涤剂胶束的性质。
Abstract In the current studies, we examined the effects of hexagonal lattice formation with lipid membranes on the structural stability of native bacteriorhodopsin (bR). Denaturation kinetic measurements for bR solubilized with the mild nonionic detergent Triton X-100 (TX100) were performed in the dark and under illumination by visible light. The solubilized bR was stable in the dark over a wide concentration range of TX100 (1 to 200 mM). In purple membranes, a bilobed band was observed in visible circular dichroism spectra due to interactions between neighboring chromophores. At all concentrations of TX100, this was replaced by a single positive band. Upon illumination with visible light, TX100-solubilized bR clearly showed photobleaching to bacterioopsin. These experimental results suggest that photobleaching is due to a lack of intermolecular interactions inside the purple membrane lattice. Extensive kinetic measurements further revealed that the rate constant of photobleaching is strongly dependent on the detergent concentration, although the activation energy for photobleaching does not significantly change with the TX100 concentration. The mechanism of photobleaching for the solubilized bR is discussed with respect to detergent micelle properties.