LOCATION OF EXIT CHANNEL FOR NASCENT PROTEIN IN 80S RIBOSOME
LOCATION OF EXIT CHANNEL FOR NASCENT PROTEIN IN 80S RIBOSOME
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DOI：
10.1038/319693a0
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发表时间：
1986-02-20
期刊：
影响因子：
64.8
通讯作者：
UNWIN, PNT
中科院分区：
文献类型：
--
作者：
MILLIGAN, RA;UNWIN, PNT
核糖体结晶内质网膜卵母细胞的意大利南部蜥蜴，蜥蜴，在冬季1。晶体的电子晶体学研究已经阐明了核糖体亚基在膜表面的排列2，3。我们现在已经从鸡胚核糖体中获得了更广泛、更有序的相同习性的晶体，并在此报告了通过将晶体快速冷冻在薄水膜中而保存的天然结构。三维图谱揭示了蛋白质和核糖体RNA在核糖体内分布的新细节。最引人注目的是大亚基内的一个低密度区域，该区域从亚基界面延伸到面向膜的表面上的一个区域，该区域被其他人确定为新生蛋白质的出口位点。这个低密度区域似乎描绘了生长多肽通过核糖体到达外表面的路径。
Ribosomes crystallize on endoplasmic reticulum membranes in oocytes of the southern Italian lizard,Lacerta sicula, during winter1. Electron crystallographic studies of the crystals have been made to elucidate the arrangement of the ribosomal subunits on the membrane surface2,3. We have now obtained more extensive and better ordered crystals of the same habit, grown from chick embryo ribosomes4, and report here on their native structure preserved by rapid freezing of the crystals in thin aqueous films. The three-dimensional map reveals new details of the protein and ribosomal RNA distribution within the ribosome. Most striking is a region of low density within the large subunit which extends from the subunit interface towards an area on the membrane-facing surface identified by others5,6as the exit site of the nascent protein. This region of low density appears to delineate the path taken by the growing polypeptide through the ribosome to the external surface.