缓冲液对光激发细菌视紫红质突变体电信号的影响。

Buffer effects on electric signals of light-excited bacteriorhodopsin mutants.

作者信息

Tóth-Boconádi R, Dér A, Taneva S G, Tuparev N P, Keszthelyi L

机构信息

Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences, Szeged.

出版信息

Eur Biophys J. 2001;30(2):140-6. doi: 10.1007/s002490100132.

DOI:10.1007/s002490100132

PMID:11409465

Abstract

The effects of glycyl-glycine and bis-trispropane buffers on the light-excited electric signals due to proton motion in the molecule were studied for the bacteriorhodopsin (bR) mutants D38R, D96N, E204Q, R227Q, D85N, D85T, R82Q/D85N, and D85N/D96N in purple membranes and for delipidated purple membrane containing the wild-type bR. The results show additional charge motion caused by the buffers in all cases. Arrhenius parameters calculated from the temperature dependence of the difference signals (with buffer minus without buffer) are similar to the parameters found for the wild-type bR in the case of these buffers: the values of the activation enthalpies are mostly in the range 25-50 kJ/mol; all the activation entropies are negative. The results are evaluated with the cluster hypothesis outlined previously.

摘要

研究了甘氨酰甘氨酸和双三羟甲基氨基甲烷缓冲液对紫色膜中细菌视紫红质（bR）突变体D38R、D96N、E204Q、R227Q、D85N、D85T、R82Q/D85N和D85N/D96N以及含有野生型bR的脱脂紫色膜中因分子内质子运动而产生的光激发电信号的影响。结果表明，在所有情况下缓冲液都会引起额外的电荷运动。根据差值信号（有缓冲液减去无缓冲液）的温度依赖性计算出的阿伦尼乌斯参数与在这些缓冲液情况下野生型bR的参数相似：活化焓值大多在25-50 kJ/mol范围内；所有活化熵均为负值。用先前概述的簇假说对结果进行了评估。