Arkin I T, Sukharev S I, Blount P, Kung C, Brünger A T
Department of Molecular Biophysics and Biochemistry, Howard Hughes Medical Institute, Yale University, New Haven, CT 06520, USA.
Biochim Biophys Acta. 1998 Feb 2;1369(1):131-40. doi: 10.1016/s0005-2736(97)00219-8.
In this report, we present structural studies on the large conductance mechanosensitive ion channel (MscL) from E. coli in detergent micelles and lipid vesicles. Both transmission Fourier transform infrared spectroscopy and circular dichroism (CD) spectra indicate that the protein is highly helical in detergents as well as liposomes. The secondary structure of the proteins was shown to be highly resistant towards denaturation (25-95 degrees C) based on an ellipticity thermal profile. Amide H+/D+ exchange was shown to be extensive (ca. 66%), implying that two thirds of the protein are water accessible. MscL, reconstituted in oriented lipid bilayers, was shown to possess a net bilayer orientation using dichroic ratios measured by attenuated total-reflection Fourier transform infrared spectroscopy. Here, we present and discuss this initial set of structural data on this new family of ion-channel proteins.
在本报告中，我们展示了对来自大肠杆菌的大电导机械敏感离子通道（MscL）在去污剂胶束和脂质囊泡中的结构研究。傅里叶变换红外光谱和圆二色性（CD）光谱均表明，该蛋白质在去污剂以及脂质体中均具有高度螺旋结构。基于椭圆率热分布图，蛋白质的二级结构显示出对变性（25 - 95摄氏度）具有高度抗性。酰胺H⁺/D⁺交换显示出广泛存在（约66%），这意味着三分之二的蛋白质可与水接触。通过衰减全反射傅里叶变换红外光谱测量的二色性比率表明，重构在定向脂质双分子层中的MscL具有净双分子层取向。在此，我们展示并讨论关于这个新的离子通道蛋白家族的这组初始结构数据。
