Chemical control of structure and guest uptake by a conformationally mobile porous material
Chemical control of structure and guest uptake by a conformationally mobile porous material
复制标题
DOI：
10.1038/s41586-018-0820-9
复制
发表时间：
2019-01-10
期刊：
影响因子：
64.8
通讯作者：
Rosseinsky, Matthew J.
中科院分区：
文献类型：
--
作者：
Katsoulidis, Alexandros P.;Antypov, Dmytro;Rosseinsky, Matthew J.
金属有机框架（MOFs）是通过将有机连接剂结合到金属节点上形成的结晶合成多孔材料：它们可以是刚性的（1，2）或柔性的（3）。沸石和刚性M0F在吸附、分离和催化中具有广泛的应用，这是由于它们能够通过由它们的化学和结构限定的它们的内表面的形状和功能来控制它们的孔中的客体分子的排列和化学（4，5）。它们的结构对应于一个具有单一但功能性很强的最低能量的能量景观。相比之下，蛋白质通过使用多肽的键旋转在多个亚稳结构之间导航来发挥作用（6，7），其中每个结构位于构象能量景观的最小值之一，并且可以根据与蛋白质相互作用的分子的化学性质进行选择。这些结构变化是通过构象选择（其中蛋白质的高能量最小特征通过小分子结合来稳定）和诱导拟合（其中小分子对蛋白质施加结构，该结构在不存在该分子的情况下不是最小值）的机制实现的（8）。在这里，我们表明，在一个肽接头的共价键旋转可以改变一个灵活的MOF提供九个不同的晶体结构，揭示了构象能量景观，其特征在于多个结构最小值。MOF对小分子客体的吸收可以通过诱导肽构象变化来化学触发。这种变化将材料从对客人吸附无活性的景观上的最小值转变为活性物质。柔性有机连接体的构象的化学控制提供了一种改变孔几何形状和内表面化学的途径，从而改变开放框架材料的功能。
Metal-organic frameworks (MOFs) are crystalline synthetic porous materials formed by binding organic linkers to metal nodes: they can be either rigid(1,2) or flexible(3). Zeolites and rigid MOFs have widespread applications in sorption, separation and catalysis that arise from their ability to control the arrangement and chemistry of guest molecules in their pores via the shape and functionality of their internal surface, defined by their chemistry and structure(4,5). Their structures correspond to an energy landscape with a single, albeit highly functional, energy minimum. By contrast, proteins function by navigating between multiple metastable structures using bond rotations of the polypeptide(6,7), where each structure lies in one of the minima of a conformational energy landscape and can be selected according to the chemistry of the molecules that interact with the protein. These structural changes are realized through the mechanisms of conformational selection (where a higher-energy minimum characteristic of the protein is stabilized by small-molecule binding) and induced fit (where a small molecule imposes a structure on the protein that is not a minimum in the absence of that molecule)(8). Here we show that rotation about covalent bonds in a peptide linker can change a flexible MOF to afford nine distinct crystal structures, revealing a conformational energy landscape that is characterized by multiple structural minima. The uptake of small-molecule guests by the MOF can be chemically triggered by inducing peptide conformational change. This change transforms the material from a minimum on the landscape that is inactive for guest sorption to an active one. Chemical control of the conformation of a flexible organic linker offers a route to modifying the pore geometry and internal surface chemistry and thus the function of open-framework materials.