Department of Biology, Chemistry, Pharmacy, Freie Universität Berlin, Altensteinstraße 23a, 14195 Berlin, Germany.
Fritz Haber Institute of the Max Planck Society, Faradayweg 4-6, 14195 Berlin, Germany.
Phys Chem Chem Phys. 2024 Nov 13;26(44):28155-28160. doi: 10.1039/d4cp03823a.
The incorporation of fluorine into amino acids is an important strategy to produce tailored building blocks with unique properties for peptide-based materials. Phenylalanine is frequently modified due to its role in cation-π interactions and the formation of amyloid fibres. Previous studies have utilized gas-phase vibrational spectroscopy to study interactions between canonical amino acids. In this study, we employ a combination of cryogenic gas-phase infrared spectroscopy and density functional theory to study the interactions in proton-bound dimers of side-chain fluorinated phenylalanines. Our findings reveal how the position and number of fluorine atoms affect the interactions and structures of the dimers. Monofluorinated phenylalanines adopt charge-solvated structures in which the two amino acids interact their ammonium and amine functions (NH⋯NH). The dimer with the perfluorinated side chain forms multiple charge-solvated and salt-bridged structures with varying interaction types. These structural changes are attributed to the significant reduction of electron density in the aromatic systems.
将氟原子引入氨基酸中是一种重要的策略，可以生产具有独特性质的肽基材料的定制结构单元。由于苯丙氨酸在阳离子-π 相互作用和淀粉样纤维形成中的作用，它经常被修饰。先前的研究利用气相振动光谱研究了典型氨基酸之间的相互作用。在这项研究中，我们结合低温气相红外光谱和密度泛函理论研究了侧链氟化苯丙氨酸质子束缚二聚体中的相互作用。我们的研究结果揭示了氟原子的位置和数量如何影响二聚体的相互作用和结构。单氟化苯丙氨酸采用电荷溶剂化结构，其中两个氨基酸通过其铵和胺功能（NH⋯NH）相互作用。具有全氟侧链的二聚体形成具有不同相互作用类型的多种电荷溶剂化和盐桥结构。这些结构变化归因于芳香体系中电子密度的显著降低。
