Methyl transfer by substrate signaling from a knotted protein fold.
Methyl transfer by substrate signaling from a knotted protein fold.
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DOI：
10.1038/nsmb.3282
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发表时间：
2016-10
影响因子：
16.8
通讯作者：
Hou YM
中科院分区：
文献类型：
--
作者：
Christian T;Sakaguchi R;Perlinska AP;Lahoud G;Ito T;Taylor EA;Yokoyama S;Sulkowska JI;Hou YM
相对于未打结的蛋白质，具有打结构型的蛋白质在构象空间上受到限制。鲜为人知的是，如果打结蛋白质有足够的动力学空间分离的底物结合位点之间的通信。在细菌中，TrmD是一种甲基转移酶，它使用打结的蛋白质折叠来催化甲基从S-腺苷甲硫氨酸（S-腺苷甲硫氨酸）转移到G37-tRNA。其产物m1 G37-tRNA作为维持蛋白质合成阅读框的决定因素，是生命所必需的。使用结构，动力学和计算分析的综合方法，我们在这里表明，结构约束的TrmD结是其催化活性所需的。出乎意料的是，TrmD结具有复杂的内部运动，响应于TCMet结合和信号传导。大多数信号传导传播了α-Met结合的自由能以稳定tRNA结合并组装活性位点。这项工作展示了结作为一个有组织的结构，捕获底物结合的自由能，以促进催化的新原则。
Proteins with knotted configurations are restricted in conformational space relative to unknotted proteins. Little is known if knotted proteins have sufficient dynamics to communicate between spatially separated substrate-binding sites. In bacteria, TrmD is a methyl transferase that uses a knotted protein fold to catalyze methyl transfer from S-adenosyl methionine (AdoMet) to G37-tRNA. The product m1G37-tRNA is essential for life as a determinant to maintain protein synthesis reading-frame. Using an integrated approach of structure, kinetic, and computational analysis, we show here that the structurally constrained TrmD knot is required for its catalytic activity. Unexpectedly, the TrmD knot has complex internal movements that respond to AdoMet binding and signaling. Most of the signaling propagates the free energy of AdoMet binding to stabilize tRNA binding and to assemble the active site. This work demonstrates new principles of knots as an organized structure that captures the free energies of substrate binding to facilitate catalysis.