The regulation of natural helical nanostructures is principally supported and actuated by hydrogen bonds (H-bonds) formed from hydrogen-bonding groups (peptide bonds and base pairs) to realize biological activities and specific biofunctional transformations. However, studying the role of H-bonding patterns on the handedness of supramolecular assemblies is still challenging, since supramolecular assemblies will be disassembled or destabilized with slightly varying H-bonding groups for most supramolecules. To circumvent this issue, herein, two types of self-assembled C2-symmetric phenylalanine derivatives differed by a single H-bonding group (ester or amide) are systematically designed for deciphering the role of H-bonding pattern on the chirality of supramolecular assemblies and their related biostability. Opposite handedness nanofibrous structures with tailorable diameter and helical pitch are achieved with the transition from ester to amide groups in the gelators. Experimental and theoretical evidence suggests that helical orientation of ester-containing gelators ascribes to intermolecular H-bonds. In contrast, the helical direction for the amide-counterparts is mainly due to intra- and intermolecular H-bonds. Moreover, these H-bonding groups greatly influence their stability, as revealed by in vitro and in vivo degradation experiments and the left-handed assemblies are more stable than the right-handed ones. Thus, the study offers a feasible model to have valuable insight into understanding the role of H-bonding patterns in biological folding.

中文翻译：

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具有可控生物稳定性的氢键调节超分子手性

天然螺旋纳米结构的调控主要由氢键基团（肽键和碱基对）形成的氢键（H-bonds）支持和驱动，以实现生物活性和特定的生物功能转化。然而，研究氢键模式对超分子组装体的旋向性的作用仍然具有挑战性，因为对于大多数超分子来说，超分子组装体会因氢键基团的轻微变化而被分解或不稳定。为了规避这个问题，本文系统地设计了两种类型的自组装 C2 对称苯丙氨酸衍生物，它们具有单个 H 键基团（酯或酰胺），用于破译 H 键模式对超分子组装手性的作用和相关的生物稳定性。通过凝胶剂中酯基团向酰胺基团的转变，实现了具有可定制直径和螺距的相反旋向纳米纤维结构。实验和理论证据表明，含酯凝胶剂的螺旋取向归因于分子间氢键。相反，酰胺对应物的螺旋方向主要是由于分子内和分子间的氢键。此外，这些氢键基团极大地影响了它们的稳定性，正如体外和体内降解实验所揭示的那样，左手组装体比右手组装体更稳定。因此，该研究提供了一个可行的模型，有助于深入了解氢键模式在生物折叠中的作用。