Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA 94720.
Department of Chemical Engineering & Materials Science, University of California, Irvine, Irvine, CA 92697.
Proc Natl Acad Sci U S A. 2018 May 29;115(22):5647-5651. doi: 10.1073/pnas.1800397115. Epub 2018 May 14.
The conformations adopted by the molecular constituents of a supramolecular assembly influence its large-scale order. At the same time, the interactions made in assemblies by molecules can influence their conformations. Here we study this interplay in extended flat nanosheets made from nonnatural sequence-specific peptoid polymers. Nanosheets exist because individual polymers can be linear and untwisted, by virtue of polymer backbone elements adopting alternating rotational states whose twists oppose and cancel. Using molecular dynamics and quantum mechanical simulations, together with experimental data, we explore the design space of flat nanostructures built from peptoids. We show that several sets of peptoid backbone conformations are consistent with their being linear, but the specific combination observed in experiment is determined by a combination of backbone energetics and the interactions made within the nanosheet. Our results provide a molecular model of the peptoid nanosheet consistent with all available experimental data and show that its structure results from a combination of intra- and intermolecular interactions.
超分子组装中分子成分所采取的构象影响其大规模有序性。同时，分子在组装中形成的相互作用也会影响它们的构象。在这里，我们研究了由非天然序列特异性肽聚合物制成的扩展平面纳米片之间的这种相互作用。纳米片的存在是因为单个聚合物可以是线性且未扭曲的，这是由于聚合物主链元素采用交替的旋转状态，其扭转相互抵消。我们使用分子动力学和量子力学模拟以及实验数据来探索由肽构建的平面纳米结构的设计空间。我们表明，有几组肽主链构象与线性一致，但在实验中观察到的特定组合是由主链能量和纳米片中形成的相互作用共同决定的。我们的结果提供了一个与所有现有实验数据一致的肽纳米片的分子模型，并表明其结构是由分子内和分子间相互作用共同作用的结果。
