Engel A, Massalski A
Ultramicroscopy. 1984;13(1-2):71-83. doi: 10.1016/0304-3991(84)90058-5.
The 3D structure of stain-penetrated transmembrane channels of E. coli outer membrane porin has been reconstructed from electron microscopic projections. The averaged unit cells of the projected hexagonal porin lattices were calculated by correlation averaging. Amplitude and phase values along the continuous lattice lines were obtained from the unit cell transforms, and continuous curves were fitted using either a cubic spline-fit or by convolution with an appropriate sinc function. The reconstructed model shows that the three channels of a porin triplet merge to a single channel while traversing the membrane. This is in excellent agreement with results of functional studies. Some technical difficulties and limitations as well as the potential of the reconstruction process are discussed.
大肠杆菌外膜孔蛋白的染色渗透跨膜通道的三维结构已从电子显微镜投影中重建。通过相关平均法计算了投影六边形孔蛋白晶格的平均晶胞。沿连续晶格线的振幅和相位值从晶胞变换中获得，并使用三次样条拟合或与适当的辛格函数卷积来拟合连续曲线。重建模型表明，孔蛋白三联体的三个通道在穿过膜时合并为一个通道。这与功能研究结果非常吻合。讨论了一些技术困难和局限性以及重建过程的潜力。
