ORGANIC CHEMISTRY Allosteric initiation and regulation of catalysis with a molecular knot
ORGANIC CHEMISTRY Allosteric initiation and regulation of catalysis with a molecular knot
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DOI：
10.1126/science.aaf3673
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发表时间：
2016-06-24
期刊：
影响因子：
56.9
通讯作者：
Leigh, David A.
中科院分区：
文献类型：
--
作者：
Marcos, Vanesa;Stephens, Alexander J.;Leigh, David A.
分子结存在于DNA、蛋白质和其他大分子中。然而，在大多数情况下，将分子打结可能带来的好处还不清楚。在这里，我们报告了一种合成分子五叶结，它通过控制碳正离子的原位生成来变构启动或调节催化的化学反应，该碳正离子是通过结促进的碳-卤键断裂形成的。结结构对于该功能是至关重要的，因为它限制了分子链可以采用的构象，并防止在金属离子结合时形成催化惰性物质。未打结的类似物没有催化活性。我们的研究结果表明，打结分子可能是一个有用的策略，减少灵活的链的自由度，使他们能够采用什么，否则无法访问的功能构象。
Molecular knots occur in DNA, proteins, and other macromolecules. However, the benefits that can potentially arise from tying molecules in knots are, for the most part, unclear. Here, we report on a synthetic molecular pentafoil knot that allosterically initiates or regulates catalyzed chemical reactions by controlling the in situ generation of a carbocation formed through the knot-promoted cleavage of a carbon-halogen bond. The knot architecture is crucial to this function because it restricts the conformations that the molecular chain can adopt and prevents the formation of catalytically inactive species upon metal ion binding. Unknotted analogs are not catalytically active. Our results suggest that knotting molecules may be a useful strategy for reducing the degrees of freedom of flexible chains, enabling them to adopt what are otherwise thermodynamically inaccessible functional conformations.