Schlesinger S, Schlesinger M J
J Virol. 1972 Nov;10(5):925-32. doi: 10.1128/JVI.10.5.925-932.1972.
Exposure of Sindbis virus-infected chicken embryo cells to a short pulse of radioactive amino acids revealed the formation of primarily three proteins: the nucleocapsid (C) of the virus, one of the viral envelope proteins (E1), and a glycoprotein that did not appear in the virion. This third protein (PE2) has now been identified as a precursor of the other viral envelope protein (E2) on the basis of two observations: (i) the simultaneous disappearance of radioactive PE2 and appearance of labeled E2 in pulse-chase experiments, and (ii) the identity of (14)C-arginine tryptic peptides in fingerprints of the two proteins. The nucleocapsid was the most heavily labeled protein in the cell and appeared in the virus during the short pulse. The two (14)C-labeled envelope proteins, although having different kinetics of labeling in the cell, appeared simultaneously in the virus only after the chase. Addition of pactamycin, a drug inhibiting initiation of protein synthesis, preferentially inhibited the formation of capsid protein Assuming that Sindbis virus proteins are formed initially as a single polypeptide, our studies locate the nucleocapsid at the amino-terminal end of the polypeptide chain.
用放射性氨基酸短脉冲处理感染辛德毕斯病毒的鸡胚细胞，结果显示主要形成了三种蛋白质：病毒核衣壳（C）、一种病毒包膜蛋白（E1）以及一种不出现在病毒粒子中的糖蛋白。基于以下两点观察，现在已将这种第三种蛋白质（PE2）鉴定为另一种病毒包膜蛋白（E2）的前体：（i）在脉冲追踪实验中，放射性PE2同时消失，标记的E2出现；（ii）两种蛋白质指纹图谱中（14）C-精氨酸胰蛋白酶肽的一致性。核衣壳是细胞中标记最重的蛋白质，在短脉冲期间出现在病毒中。两种（14）C标记的包膜蛋白，尽管在细胞中的标记动力学不同，但仅在追踪后才同时出现在病毒中。添加抑制蛋白质合成起始的药物 pactamycin，优先抑制衣壳蛋白的形成。假设辛德毕斯病毒蛋白最初以单一多肽形式形成，我们的研究将核衣壳定位在多肽链的氨基末端。
