The shape of the bacterial ribosome exit tunnel affects cotranslational protein folding.
The shape of the bacterial ribosome exit tunnel affects cotranslational protein folding.
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DOI：
10.7554/elife.36326
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发表时间：
2018-11-26
期刊：
影响因子：
7.7
通讯作者：
von Heijne G
中科院分区：
文献类型：
--
作者：
Kudva R;Tian P;Pardo-Avila F;Carroni M;Best RB;Bernstein HD;von Heijne G
大肠杆菌核糖体出口通道可以容纳小的折叠蛋白质，而大的蛋白质则折叠在外面。然而，目前还不清楚隧道的几何形状对蛋白质折叠的影响程度。在这里，使用在突出到隧道中的蛋白质uL23和uL24的环中缺失的大肠杆菌核糖体，我们研究隧道几何形状如何决定不同大小的蛋白质在哪里折叠。我们发现，在uL23Δ环核糖体中，一个29个残基的锌指结构域在uL23环附近折叠得更深，而在uL24Δ环核糖体中，两个~100个残基蛋白质通常在隧道出口附近的uL24环附近折叠，在uL24环核糖体中更深的位置折叠，这与粗粒度分子动力学模拟的结果一致。这支持了这样的想法，即一旦蛋白质结构域到达出口隧道中有足够空间容纳折叠结构的位置，共翻译折叠就开始了。
The E. coli ribosome exit tunnel can accommodate small folded proteins, while larger ones fold outside. It remains unclear, however, to what extent the geometry of the tunnel influences protein folding. Here, using E. coli ribosomes with deletions in loops in proteins uL23 and uL24 that protrude into the tunnel, we investigate how tunnel geometry determines where proteins of different sizes fold. We find that a 29-residue zinc-finger domain normally folding close to the uL23 loop folds deeper in the tunnel in uL23 Δloop ribosomes, while two ~ 100 residue proteins normally folding close to the uL24 loop near the tunnel exit port fold at deeper locations in uL24 Δloop ribosomes, in good agreement with results obtained by coarse-grained molecular dynamics simulations. This supports the idea that cotranslational folding commences once a protein domain reaches a location in the exit tunnel where there is sufficient space to house the folded structure.