The polypeptide tunnel system in the ribosome and its gating in erythromycin resistance mutants of L4 and L22
The polypeptide tunnel system in the ribosome and its gating in erythromycin resistance mutants of L4 and L22
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DOI：
10.1016/s1097-2765(01)00293-3
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发表时间：
2001-07-01
期刊：
影响因子：
16
通讯作者：
Frank, J
中科院分区：
文献类型：
--
作者：
Gabashvili, IS;Gregory, ST;Frank, J
通过红霉素抗性大肠杆菌 70S 核糖体的三维冷冻电子显微镜研究了决定新生蛋白质运输拓扑的内部核糖体景观的变化。本研究中可视化的 50S 亚基隧道系统口的显着差异支持对药物作用的简单空间位阻解释。对不同功能状态下核糖体的检查表明，主通道的打开和关闭是大亚基的动态特征，可能伴随着 L7/L12 柄区域的变化。侧通道的存在和动态行为表明核糖体蛋白 L4 和 L22 可能参与促进新生蛋白共翻译加工（或折叠或引导）的多重出口系统的调节。
Variations in the inner ribosomal landscape determining the topology of nascent protein transport have been studied by three-dimensional cryo-electron microscopy of erythromycin-resistant Escherichia coli 70S ribosomes. Significant differences in the mouth of the 50S subunit tunnel system visualized in the present study support a simple steric-hindrance explanation for the action of the drug. Examination of ribosomes in different functional states suggests that opening and closing of the main tunnel are dynamic features of the large subunit, possibly accompanied by changes in the L7/L12 stalk region. The existence and dynamic behavior of side tunnels suggest that ribosomal proteins L4 and L22 might be involved in the regulation of a multiple exit system facilitating cotranslational processing (or folding or directing) of nascent proteins.