Materials Department, University of California, Santa Barbara, California 93106, USA.
Materials Research Laboratory, University of California, Santa Barbara, California 93106, USA.
Nat Chem. 2017 May;9(5):473-479. doi: 10.1038/nchem.2720. Epub 2017 Feb 13.
Cation-π interactions drive the self-assembly and cohesion of many biological molecules, including the adhesion proteins of several marine organisms. Although the origin of cation-π bonds in isolated pairs has been extensively studied, the energetics of cation-π-driven self-assembly in molecular films remains uncharted. Here we use nanoscale force measurements in combination with solid-state NMR spectroscopy to show that the cohesive properties of simple aromatic- and lysine-rich peptides rival those of the strong reversible intermolecular cohesion exhibited by adhesion proteins of marine mussel. In particular, we show that peptides incorporating the amino acid phenylalanine, a functional group that is conspicuously sparing in the sequences of mussel proteins, exhibit reversible adhesion interactions significantly exceeding that of analogous mussel-mimetic peptides. More broadly, we demonstrate that interfacial confinement fundamentally alters the energetics of cation-π-mediated assembly: an insight that should prove relevant for diverse areas, which range from rationalizing biological assembly to engineering peptide-based biomaterials.
阳离子-π 相互作用驱动许多生物分子的自组装和内聚，包括几种海洋生物的粘附蛋白。尽管已经广泛研究了孤立对中阳离子-π 键的起源，但分子膜中阳离子-π 驱动的自组装的能量学仍未被探索。在这里，我们使用纳米尺度力测量结合固态 NMR 光谱学表明，简单芳香族和赖氨酸丰富的肽的内聚性质可与贻贝类粘附蛋白所表现出的强可逆分子间内聚相媲美。具体而言，我们表明，包含氨基酸苯丙氨酸的肽，其功能基团在贻贝类蛋白质序列中明显稀少，表现出显著超过类似贻贝类模拟肽的可逆粘附相互作用。更广泛地说，我们证明界面限制从根本上改变了阳离子-π 介导的组装的能量学：这一见解对于从合理化生物组装到工程肽基生物材料的各个领域都应该是相关的。
