Michel H, Oesterhelt D
Proc Natl Acad Sci U S A. 1980 Mar;77(3):1283-5. doi: 10.1073/pnas.77.3.1283.
The intrinsic membrane protein bacteriorhodopsin has been crystallized by salt precipitation after solubilization by octyl glucoside. Two different crystal forms were obtained, depending on the nature of the salt used and the pH. Needles formed in the presence of sodium phosphate and in ammonium sulfate solutions above pH 4.8. Cubes appeared in sodium citrate solutions or ammonium sulfate. Unlike the cubic crystals, the birefringent needles showed strong linear dichroism, which allowed determination of the orientation of the chromophore's transition moment. The procedure described here may be of general use in crystallographic studies of membrane proteins.
内在膜蛋白细菌视紫红质在经辛基葡糖苷增溶后通过盐沉淀法结晶。根据所用盐的性质和pH值，获得了两种不同的晶体形式。在磷酸钠存在下以及在pH值高于4.8的硫酸铵溶液中形成针状晶体。在柠檬酸钠溶液或硫酸铵中出现立方晶体。与立方晶体不同，双折射针状晶体表现出强烈的线性二色性，这使得能够确定发色团跃迁矩的方向。这里描述的方法可能在膜蛋白的晶体学研究中具有普遍用途。
