Lunev A V, Demin V V, Zaĭtsev O I, Spadir S I, Grishin E V
Bioorg Khim. 1991 Aug;17(8):1021-6.
Two-dimensional crystals of alpha-latrotoxin from the venom of black widow spider (Latrodectus mactans tredecimguttatus) were studied by the negative staining electron microscopy. Two-dimensional crystals were obtained by adsorption of the protein solution with a high Mg2+ concentration on carbon-coated electron microscopy grids. The crystals were about 0.4 mkm in size, had the unit cell parameters: a = b = 15.55 nm, gamma = 90 degrees, p4 plane group symmetry. The contour map of a stain-excluding region of such crystals was calculated by the Fourier-filtering procedure at about 4 nm resolution. The calculation of molecular weight of the unit cell, with the symmetry p4 taken into account, showed that alpha-latrotoxin particles, revealed by negative staining, consisted of 4 or 8 protomers.
利用负染色电子显微镜对来自黑寡妇蜘蛛（间斑寇蛛）毒液中的α-拉托毒素二维晶体进行了研究。通过将高Mg2+浓度的蛋白质溶液吸附在碳涂层电子显微镜网格上获得二维晶体。这些晶体尺寸约为0.4μm，其晶胞参数为：a = b = 15.55nm，γ = 90°，具有p4平面群对称性。通过傅里叶滤波程序在约4nm分辨率下计算了此类晶体的染色排除区域的轮廓图。考虑到p4对称性，对晶胞分子量的计算表明，负染色显示的α-拉托毒素颗粒由4个或8个原体组成。
