细菌视紫红质在有机溶剂中的变性。

Denaturation of bacteriorhodopsin by organic solvents.

作者信息

Mitaku S, Ikuta K, Itoh H, Kataoka R, Naka M, Yamada M, Suwa M

机构信息

Department of Material Systems Engineering, Faculty of Technology, Tokyo University of Agriculture and Technology, Nakamachi Koganei, Tokyo 184, Japan.

出版信息

Biophys Chem. 1988 May;30(1):69-79. doi: 10.1016/0301-4622(88)85005-1.

DOI:10.1016/0301-4622(88)85005-1

PMID:17010918

Abstract

The denaturation of bacteriorhodopsin by various organic solvents was studied using absorption, circular dichroism (CD) and fluorescence measurements. Organic solvents with a hydrogen-bonding group caused the release of retinal. The CD measurements showed that the helical structure was maintained even in the denatured state, whereas its tertiary structure was destroyed. The change in fluorescence intensity of tryptophan and fluorescent retinal also confirmed that the tertiary structure was destroyed. Comparison of the denaturation efficiency of various organic solvents showed that the concentration at denaturation was inversely proportional to the partition coefficient of the denaturant. This inverse proportionality clearly indicated that denaturation was determined by the concentration of denaturants which partitioned into the hydrophobic region of the membrane. It was discussed from the experimental results that the tertiary structure of bacteriorhodopsin was stabilized by the hydrogen-bonding networks between side chains of the helices. The results obtained from analysis of the amino acid sequence were also consistent with the hydrogen-bonding mechanism for the formation of the tertiary structure.

摘要

利用吸收光谱、圆二色光谱（CD）和荧光测量技术，研究了多种有机溶剂对细菌视紫红质的变性作用。带有氢键基团的有机溶剂会导致视黄醛的释放。CD测量结果表明，即使在变性状态下，螺旋结构仍得以保留，但其三级结构遭到破坏。色氨酸和荧光视黄醛荧光强度的变化也证实了三级结构已被破坏。对各种有机溶剂变性效率的比较表明，变性时的浓度与变性剂的分配系数成反比。这种反比关系清楚地表明，变性是由分配到膜疏水区域的变性剂浓度决定的。从实验结果讨论得出，细菌视紫红质的三级结构是由螺旋侧链之间的氢键网络稳定的。氨基酸序列分析结果也与三级结构形成的氢键机制一致。