Key Laboratory of Colloid and Interface Chemistry of Ministry of Education and School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, People's Republic of China.
J Phys Chem Lett. 2021 Jul 8;12(26):6190-6196. doi: 10.1021/acs.jpclett.1c01231. Epub 2021 Jun 30.
The hydration effect on the folding behavior of oligopeptides is of vital importance both in the structure basis of biomolecules and in the rational design of peptide-based materials, which however has rarely been addressed. Here we present the hydration impact on the spontaneous folding of dipeptides conjugated by the ferrocene spacer. In organic phase, the ferrocene-glycine-phenylalanine dipeptide formed a parallel β-sheet structure and Herrick's conformation, which underwent conformational transformation encountering aqueous media, by significantly switching dipeptide arm angles around the ferrocene axis up to 72°. The conformational transformation behavior aroused inversion of the chiroptical activity. Solid X-ray structures, proton nuclear magnetic resonance, chiroptical spectroscopy, and the density functional theory calculation were employed to unveil the hydration effect in the secondary structure transition, in which the rearrangement of hydrogen bonds played the vital role. This work deepens the understanding of water functioning in the structure modulation of biomolecules and also provides an alternative protocol in designing novel chiroptical switches and adaptive peptide-based biomaterials.
水合作用对寡肽折叠行为的影响在生物分子的结构基础和基于肽的材料的合理设计中都至关重要，但这方面的研究却很少涉及。在这里，我们研究了水合作用对二肽自发折叠的影响，该二肽由二茂铁间隔基连接。在有机相中，二茂铁-甘氨酸-苯丙氨酸二肽形成了平行的β-折叠结构和 Herrick 构象，当遇到水相时，通过二茂铁轴周围二肽臂角度显著切换高达 72°，会发生构象转变。构象转变行为引起手性活性的反转。采用固体 X 射线结构、质子核磁共振、手性光谱和密度泛函理论计算揭示了二级结构转变中的水合作用，其中氢键的重排起着至关重要的作用。这项工作加深了对水在生物分子结构调节中作用的理解，也为设计新型手性开关和适应性肽基生物材料提供了一种替代方案。
