Cremers A F, Schepman A M, Visser M P, Mellema J E
Eur J Biochem. 1977 Nov 1;80(2):393-400. doi: 10.1111/j.1432-1033.1977.tb11894.x.
Polymers of contracted sheath particles of bacteriophage Mu were imaged by the negative-staining technique and the electron images were analyzed by optical and digital methods. By means of the three-dimensional reconstruction technique of DeRosier and Klug [Nature (Lond.) 217, 130--134 (1968)] an averaged density map of the sheath structure at a resolution of about 2.0 nm was derived. The sheath is known to consist of one type of protein with a molecular weight of about 52000 [Admiraal and Mellema, J. Ultrastr. Res. 56, 48--64 (1976)]. The interpretation of the map has given information about packing and shape of the protein subunits. One way to describe the structure is by a set of annular rings with 6-fold symmetry. The height of these rings is about 1.8 nm and successive rings in the structure change by about 33 degrees in azimuth. The protein subunit which occupies more than one ring in the polymer, is elongated. The long axis of the protein subunit is at an angle of about 20 degrees with the plane normal to the polymer axis. These data are discussed in relation to changes in the sheath molecules upon contraction.
利用负染色技术对噬菌体Mu收缩鞘颗粒的聚合物进行成像，并通过光学和数字方法对电子图像进行分析。借助德罗西尔和克鲁格的三维重建技术[《自然》（伦敦）217, 130 - 134 (1968)]，得出了分辨率约为2.0纳米的鞘结构平均密度图。已知鞘由一种分子量约为52000的蛋白质组成[阿德米拉和梅勒马，《超微结构研究杂志》56, 48 - 64 (1976)]。对该图的解读给出了有关蛋白质亚基堆积和形状的信息。描述该结构的一种方式是通过一组具有六重对称性的环形环。这些环的高度约为1.8纳米，结构中相邻环在方位角上变化约33度。在聚合物中占据多个环的蛋白质亚基是细长的。蛋白质亚基的长轴与垂直于聚合物轴的平面成约20度角。结合收缩时鞘分子的变化对这些数据进行了讨论。
