Sosinsky G E, Baker T S, Caspar D L, Goodenough D A
Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, Massachusetts 02254-9110.
Biophys J. 1990 Nov;58(5):1213-26. doi: 10.1016/S0006-3495(90)82462-0.
Fourier averages of connexon images computed from low-irradiation electron micrographs of isolated negatively stained gap junction domains exhibited differences in stain distribution and connexon orientation. To analyze these polymorphic structures, correlation averaging methods were applied to images from negatively stained and frozen-hydrated specimens. For the negatively stained specimens, separate averages over two subsets of connexons with differing degrees of stain accumulation in the axial channel were obtained. Two populations of connexons with opposite skew orientations were distinguishable within a single junctional domain of a frozen-hydrated specimen. Correlation maps calculated using the left- and right-skewed references showed that the selected connexons tend to locally cluster. Using correlation methods to analyze packing disorder in a typical connexon lattice, we estimated the root-mean-square variation in the nearest neighbor pair separation to be approximately 11% of the lattice constant. Displacements of the connexons relative to each other increased with increasing pair separation in the lattice, rather like a liquid, although long-range orientation order was conserved as in a crystal. These results support the hypothesis that the hexagonal ordering of the connexons results from short-range repulsive forces.
从分离的经负染色的间隙连接域的低辐射电子显微照片计算得到的连接子图像的傅里叶平均值，在染色分布和连接子取向上表现出差异。为了分析这些多态结构，相关平均方法被应用于来自负染色和冷冻水合标本的图像。对于负染色标本，在轴向通道中具有不同程度染色积累的连接子的两个子集上分别进行了平均。在冷冻水合标本的单个连接域内，可以区分出具有相反倾斜取向的两类连接子。使用左斜和右斜参考计算的相关图表明，所选连接子倾向于局部聚集。通过相关方法分析典型连接子晶格中的堆积无序，我们估计最近邻对间距的均方根变化约为晶格常数的11%。连接子相对于彼此的位移随着晶格中对间距的增加而增加，有点像液体，尽管像晶体一样保持着长程取向有序。这些结果支持了连接子的六边形排列是由短程排斥力导致的这一假设。
