Scarlata S F
Division of Digestive Diseases, College of Medicine, Cornell University Medical College, New York, New York 10021.
Biophys J. 1988 Dec;54(6):1149-57. doi: 10.1016/S0006-3495(88)83049-2.
The rotational amplitude of gramicidin tryptophans was investigated as a function of temperature and viscosity in a variety of solvents using fluorescence spectroscopy. In 80% glycerol-ethanol, gramicidin behavior was similar to that of alpha helical globular proteins. In dioleoyl-phosphatidylcholine (DOPC) and egg-phosphatidylcholine bilayers, the rotational amplitude of the tryptophans remained constant from 5 degrees to 40 degrees C due to the large number of tryptophans participating in intermolecular aromatic ring stacking. In gel phase dimyristoyl-phosphatidylcholine (DMPC), the tryptophan rotations likewise do not respond to temperature and viscosity changes, presumably because of a combination of Trp 9 and 15 stacking and the high viscosity of the membrane. In fluid phase DMPC, stacking becomes disrupted as the temperature increases causing the change in tryptophan amplitude with temperature to be greater than allowed by the membrane. In n-octylglucoside micelles, ring interactions are also broken with heat. We conclude that membrane viscosity regulates both inter- and intramolecular gramicidin interactions but not in a straightforward manner.
使用荧光光谱法，研究了短杆菌肽色氨酸的旋转幅度与温度和粘度的函数关系，该研究在多种溶剂中进行。在80%甘油 - 乙醇中，短杆菌肽的行为类似于α - 螺旋球状蛋白质。在二油酰磷脂酰胆碱（DOPC）和鸡蛋磷脂酰胆碱双层膜中，由于大量色氨酸参与分子间芳环堆积，色氨酸的旋转幅度在5℃至40℃之间保持恒定。在凝胶相二肉豆蔻酰磷脂酰胆碱（DMPC）中，色氨酸的旋转同样不响应温度和粘度变化，推测这是由于Trp 9和15的堆积以及膜的高粘度共同作用的结果。在流体相DMPC中，随着温度升高，堆积被破坏，导致色氨酸幅度随温度的变化大于膜所允许的范围。在正辛基葡糖苷胶束中，环相互作用也会因加热而断裂。我们得出结论，膜粘度调节分子间和分子内短杆菌肽相互作用，但方式并不直接。
