Knots can impair protein degradation by ATP-dependent proteases.
Knots can impair protein degradation by ATP-dependent proteases.
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结会损害 ATP 依赖性蛋白酶对蛋白质的降解。
DOI：
10.1073/pnas.1705916114
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发表时间：
2017
影响因子：
11.1
通讯作者：
Baez,Mauricio
中科院分区：
文献类型：
--
作者：
SanMartín,Álvaro;Rodriguez-Aliaga,Piere;Molina,JoséAlejandro;Martin,Andreas;Bustamante,Carlos;Baez,Mauricio
ATP依赖性蛋白酶通过一个狭窄的孔转移蛋白质，以控制其破坏。然而，如何蛋白质基板含有打结拓扑结构影响这一进程仍然未知。在这里，我们的特点是三叶结蛋白MJ 0366从甲烷球菌jannaschion的ClpXP蛋白酶从大肠杆菌的操作的影响。ClpXP从C-末端ssrA-标签拉出时完全降解MJ 0366。然而，当GFP部分附加到MJ 0366的N末端时，ClpXP释放具有47个残基尾部的完整GFP。该尾部的延长长度表明ClpXP针对GFP拉紧三叶结，这防止GFP解折叠。有趣的是，如果MJ 0366的结核心和GFP之间的连接子长于36个残基，ClpXP在其到达GFP之前收紧并移位结，使得底物完全解折叠和降解。这些观察结果表明，在AAA蛋白酶降解多结构域蛋白的过程中，结诱导的失速可能构成一种新的机制，以产生具有潜在新功能的部分降解产物。
ATP-dependent proteases translocate proteins through a narrow pore for their controlled destruction. However, how a protein substrate containing a knotted topology affects this process remains unknown. Here, we characterized the effects of the trefoil-knotted protein MJ0366 fromMethanocaldococcus jannaschiion the operation of the ClpXP protease fromEscherichia coli. ClpXP completely degrades MJ0366 when pulling from the C-terminal ssrA-tag. However, when a GFP moiety is appended to the N terminus of MJ0366, ClpXP releases intact GFP with a 47-residue tail. The extended length of this tail suggests that ClpXP tightens the trefoil knot against GFP, which prevents GFP unfolding. Interestingly, if the linker between the knot core of MJ0366 and GFP is longer than 36 residues, ClpXP tightens and translocates the knot before it reaches GFP, enabling the complete unfolding and degradation of the substrate. These observations suggest that a knot-induced stall during degradation of multidomain proteins by AAA proteases may constitute a novel mechanism to produce partially degraded products with potentially new functions.