Multisite Ribosomal Stalling: A Unique Mode of Regulatory Nascent Chain Action Revealed for MifM
Multisite Ribosomal Stalling: A Unique Mode of Regulatory Nascent Chain Action Revealed for MifM
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DOI：
10.1016/j.molcel.2012.06.034
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发表时间：
2012-09-28
期刊：
影响因子：
16
通讯作者：
Ito, Koreaki
中科院分区：
文献类型：
--
作者：
Chiba, Shinobu;Ito, Koreaki
枯草芽孢杆菌MifM使用多肽指导的核糖体停滞来控制YidC 2（膜蛋白生物合成因子）的翻译。与其他涉及单个停滞点的失速系统相比，我们的体外翻译/足印实验表明，B。枯草杆菌核糖体在MifM的多个密码子处连续停滞。这种延长停滞模式取决于核糖体出口通道中间的新生链残基和位于停滞点附近的几个（最大功能性为四个）负电荷。后一个元件不需要精确的氨基酸序列，并且该特征可能是多位点停滞的基础。被抑制的新生链不能有效地转移到嘌呤霉素，表明生长的MifM新生链在获得酸性残基后抑制肽基转移酶中心。多位点停滞似乎为MifM提供了一种独特的手段，以实现调节功能所需的足够持续时间的核糖体停滞。
Bacillus subtilis MifM uses polypeptide-instructed ribosomal stalling to control translation of YidC2, a membrane protein biogenesis factor. In contrast to other stalling systems involving a single arrest point, our in vitro translation/toeprint experiments show that the B. subtilis ribosome stalls consecutively at multiple codons of MifM. This mode of elongation arrest depends on nascent chain residues at the middle of the ribosomal exit tunnel and a few (four for the maximum functionality) negative charges residing proximally to the arrest points. The latter element does not require exact amino acid sequence, and this feature may underlie the multisite stalling. The arrested nascent chains were not efficiently transferred to puromycin, suggesting that growing MifM nascent chains inhibit peptidyl transferase center after acquiring an acidic residue(s). Multisite stalling seems to provide a unique means for MifM to achieve a sufficient duration of ribosomal stalling required for the regulatory function.