Avila-Sakar A J, Chiu W
Department of Molecular Physiology and Biophysics, W. M. Keck Center for Computational Biology, Baylor College of Medicine, Houston, Texas 77030, USA.
Biophys J. 1996 Jan;70(1):57-68. doi: 10.1016/S0006-3495(96)79597-8.
The biotin-binding protein streptavidin was crystallized as two-dimensional periodic arrays on biotinylated phospholipid monolayers. Electron diffraction patterns and images of the arrays embedded in vitreous ice were recorded to near-atomic resolution. Amplitudes and phases of structure factors were computed and combined to produce a 3 A projection density map. The reliability of the map was verified by comparing it to the available x-ray atomic model of the molecule. Projection densities from beta-strands and some amino acid side chains were identified from the electron cryomicroscopy map. These results demonstrate the first near-atomic image of this type of protein periodic array by electron crystallography, which has a great potential to aid in the structural characterization of molecular arrays engineered on a monolayer for various basic or biotechnological applications.
生物素结合蛋白链霉抗生物素蛋白在生物素化磷脂单分子层上结晶为二维周期性阵列。记录了嵌入玻璃态冰中的阵列的电子衍射图案和图像，分辨率接近原子级。计算并组合了结构因子的振幅和相位，以生成3埃的投影密度图。通过将该图与该分子现有的X射线原子模型进行比较，验证了该图的可靠性。从电子冷冻显微镜图中识别出β-链和一些氨基酸侧链的投影密度。这些结果展示了通过电子晶体学获得的此类蛋白质周期性阵列的首张近原子图像，其在辅助表征为各种基础或生物技术应用而在单分子层上设计的分子阵列的结构方面具有巨大潜力。
