EVIDENCE FOR AN EXTENDED 7SL RNA STRUCTURE IN THE SIGNAL RECOGNITION PARTICLE
EVIDENCE FOR AN EXTENDED 7SL RNA STRUCTURE IN THE SIGNAL RECOGNITION PARTICLE
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DOI：
10.1002/j.1460-2075.1987.tb02671.x
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发表时间：
1987-11-01
期刊：
影响因子：
11.4
通讯作者：
OTTENSMEYER, FP
中科院分区：
文献类型：
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作者：
ANDREWS, DW;WALTER, P;OTTENSMEYER, FP
信号识别颗粒（SRP）与SRP受体一起发挥作用，将新生的胞质蛋白靶向内质网膜的蛋白质易位机制。SRP是一种核糖核蛋白，由六种不同的多肽和一个300个核苷酸长的7SL RNA分子组成。SRP以前已经通过各种电子显微镜技术可视化为24 nm长和6 nm宽的棒状颗粒。我们在这里报告微量分析的电子光谱成像定位的RNA分子在SRP主要的两个末端的颗粒。这些结果表明，单个7SL RNA分子跨越颗粒的长度。来自扫描透射电子显微镜的显微照片允许在低电子暴露下观察未染色的SRP，以及直接测量分子量。wt %的颗粒。这些显微照片证实了我们先前的建议，即SRP分为三个结构域，并允许区分结构的两端。这两种技术的结果已被结合在一个模型中的结构SRP中，我们提出的基本方向的7SL RNA。提出的结构与预测的RNA二级结构和生化数据一致。
The signal recognition particle (SRP) functions in conjunction with the SRP receptor to target nascent ectoplasmic proteins to the protein translocation machinery of the endoplasmic reticulum membrane. SRP is a ribonucleoprotein consisting of six distinct polypeptides and one molecule of 7SL RNA 300 nucleotides long. SRP has previously been visualized by a variety of electron microscopic techniques as a rod-shaped particle 24 nm long and 6 nm wide. We report here microanalysis by electron spectroscopic imaging which localizes the RNA molecule in SRP to primarily the two ends of the particle. These results suggest that the single 7SL RNA molecule spans the length of the particle. Micrographs from a scanning transmission electron microscope permit visualization of unstained SRP with low electron exposure, as well as the direct measurement of the mol. wt of the particle. These micrographs confirm our earlier suggestion that SRP is divided into three structural domains and allow discrimination of the two ends of the structure. The results of both techniques have been combined in a model for the structure of SRP in which we propose the basic orientation of the 7SL RNA. The structure proposed is consistent with the secondary structure predicted for the RNA and with biochemical data.