Kolomytkin O V, Golubok A O, Davydov D N, Timofeev V A, Vinogradova S A
Institute of Biophysics, Academy of Sciences of the USSR, Pushchino.
Biophys J. 1991 Apr;59(4):889-93. doi: 10.1016/S0006-3495(91)82301-3.
The molecular structure of channels formed by gramicidin A in a lipid membrane was imaged by a scanning tunneling microscope operating in air. The mono- and bimolecular films of lipid with gramicidin A were deposited onto a highly oriented pyrolitic graphite substrate by the Langmuir-Blodgett technique. It has been shown that under high concentration gramicidin A molecules can form in lipid films a quasi-regular, densely packed structure. Single gramicidin A molecules were imaged for the first time as well. The cavity of 0.4 +/- 0.05 nm in halfwidth was found on the scanning tunneling microscopy image of the gramicidin A molecule. The results of direct observation obtained by means of scanning tunneling microscope are in good agreement with the known molecular model of gramicidin A. It was shown that gramicidin A molecules can exist in a lipid monolayer as individual molecules or combined into clusters. The results demonstrate that scanning tunneling microscope can be used for high spatial resolution study of ionic channel structure.
利用在空气中操作的扫描隧道显微镜对脂膜中短杆菌肽A形成的通道的分子结构进行了成像。通过朗缪尔-布洛杰特技术将含有短杆菌肽A的脂质单分子膜和双分子膜沉积在高度取向的热解石墨基底上。结果表明，在高浓度下，短杆菌肽A分子可在脂质膜中形成准规则、紧密堆积的结构。首次对单个短杆菌肽A分子进行了成像。在短杆菌肽A分子的扫描隧道显微镜图像上发现了半高宽为0.4±0.05 nm的空腔。通过扫描隧道显微镜获得的直接观察结果与已知的短杆菌肽A分子模型高度吻合。结果表明，短杆菌肽A分子可以以单个分子的形式存在于脂质单层中，也可以聚集成簇。这些结果表明，扫描隧道显微镜可用于离子通道结构的高空间分辨率研究。
