The ribosomal exit tunnel functions as a discriminating gate
The ribosomal exit tunnel functions as a discriminating gate
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DOI：
10.1016/s0092-8674(02)00649-9
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发表时间：
2002-03-08
期刊：
影响因子：
64.5
通讯作者：
Ito, K
中科院分区：
文献类型：
--
作者：
Nakatogawa, H;Ito, K
除非其N端部分被蛋白质输出机制“拉动”，否则SecM的翻译会停滞。在此我们表明，包含一个特定停滞位点（脯氨酸）的序列基序FXXXXWIXXXXGIRAGP会导致在核糖体内的延伸停滞。绕过延伸停滞的突变在23S rRNA和L22核糖体蛋白中被分离出来。这类抑制突变发生在这些组分的几个特定残基上，它们都面向核糖体出口通道最狭窄的收缩部位。因此，我们认为出口通道的这一区域与新生翻译产物相互作用，并起到一个甄别门的作用。
Translation of SecM stalls unless its N-terminal part is "pulled" by the protein export machinery. Here we show that the sequence motif FXXXXWIXXXXGIRAGP that includes a specific arrest point (Pro) causes elongation arrest within the ribosome. Mutations that bypass the elongation arrest were isolated in 23S rRNA and L22 r protein. Such suppressor mutations occurred at a few specific residues of these components, which all face the narrowest constriction of the ribosomal exit tunnel. Thus, we suggest that this region of the exit tunnel interacts with nascent translation products and functions as a discriminating gate.