Goodman J M, Watts C, Wickner W
Cell. 1981 May;24(2):437-41. doi: 10.1016/0092-8674(81)90334-2.
The major coat protein (gene 8 product) of bacteriophage M13 is an integral membrane protein during infection of host cells. It is synthesized as a larger precursor (procoat) with a leader sequence of 23 amino acids at its amino terminus. In vivo studies have shown that procoat only inserts into the host-cell plasma membrane after its synthesis is completed. We now demonstrate that procoat can post-translationally insert into inverted cytoplasmic membrane vesicles from E. coli and can be processed proteolytically to yield coat protein. Procoat changes from an assembly-competent substrate to an incompetent (denatured) form within minutes after its synthesis; much of the procoat that accumulates during an hour of in vitro synthesis is therefore denatured. These studies emphasize the importance of stringent criteria for the demonstration of obligate cotranslational assembly.
噬菌体M13的主要外壳蛋白（基因8产物）在感染宿主细胞期间是一种整合膜蛋白。它作为一种较大的前体（前衣壳）合成，在其氨基末端有一个23个氨基酸的前导序列。体内研究表明，前衣壳只有在其合成完成后才插入宿主细胞质膜。我们现在证明，前衣壳可以在翻译后插入来自大肠杆菌的反向细胞质膜囊泡中，并可以通过蛋白水解加工产生衣壳蛋白。前衣壳在合成后几分钟内从一种有组装能力的底物转变为无能力（变性）的形式；因此，在体外合成一小时内积累的大部分前衣壳都变性了。这些研究强调了严格标准对于证明专一性共翻译组装的重要性。
