Alternate recruitment of signal recognition particle and trigger factor to the signal sequence of a growing nascent polypeptide
Alternate recruitment of signal recognition particle and trigger factor to the signal sequence of a growing nascent polypeptide
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DOI：
10.1074/jbc.m511388200
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发表时间：
2006-03-17
影响因子：
4.8
通讯作者：
Müller, M
中科院分区：
文献类型：
--
作者：
Eisner, G;Moser, M;Müller, M
与细胞质膜蛋白不同，细菌的分泌前蛋白通常不需要信号识别颗粒来靶向Sec易位子。然而，已经发现分泌前蛋白质的信号序列在它们从核糖体中出现后立即靠近信号识别颗粒。我们在这里表明，在核糖体，信号序列的分子环境取决于下游序列元件的性质，可以导致信号识别颗粒和核糖体相关的伴侣触发因子的交替招聘到一个不断增长的新生链。虽然信号识别颗粒和触发因子可能保持与相同的核糖体结合，但两种配体显然能够从新生链中相互置换。这些数据还表明，一个信号序列欠它的分子环境的事实，即它仍然密切apposed的核糖体出口网站在生长过程中的新生分泌蛋白。
Different from cytoplasmic membrane proteins, presecretory proteins of bacteria usually do not require the signal recognition particle for targeting to the Sec translocon. Nevertheless signal sequences of presecretory proteins have been found in close proximity to signal recognition particle immediately after they have emerged from the ribosome. We show here that at the ribosome, the molecular environment of a signal sequence depends on the nature of downstream sequence elements that can cause an alternate recruitment of signal recognition particle and the ribosome-associated chaperone Trigger factor to a growing nascent chain. While signal recognition particle and Trigger factor might remain bound to the same ribosome, both ligands are clearly able to displace each other from a nascent chain. The data also imply that a signal sequence owes its molecular environment to the fact that it remains closely apposed to the ribosomal exit site during growth of a nascent secretory protein.