This work describes the self-assembly behavior of heterochiral, aliphatic dipeptides, l-Leu-d-Xaa (Xaa = Ala, Val, Ile, Leu), in green solvents such as acetonitrile (MeCN) and buffered water at neutral pH. Interestingly, water plays a structuring role because at 1% v/v, it enables dipeptide self-assembly in MeCN to yield organogels, which then undergo transition towards crystals. Other organic solvents and oils were tested for gelation, and metastable gels were formed in tetrahydrofuran, although at high peptide concentration (80 mM). Single-crystal X-ray diffraction revealed the dipeptides' supramolecular packing modes in amphipathic layers, as opposed to water channels reported for the homochiral Leu–Leu, or hydrophobic columns reported for homochiral Leu–Val and Leu–Ile.

中文翻译：

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异手性脂肪族二肽与 Leu 的自组装

这项工作描述了异手性脂肪族二肽l -Leu- d -Xaa（Xaa = Ala、Val、Ile、Leu）在乙腈 (MeCN) 等绿色溶剂和中性 pH 值缓冲水中的自组装行为。有趣的是，水起着结构化作用，因为在 1% v/v 时，它使二肽在 MeCN 中自组装产生有机凝胶，然后转变为晶体。测试了其他有机溶剂和油的凝胶作用，并在四氢呋喃中形​​成了亚稳态凝胶，尽管肽浓度很高（80 mM）。单晶 X 射线衍射揭示了两亲层中二肽的超分子堆积模式，这与报道的纯手性 Leu-Leu 的水通道或报道的纯手性 Leu-Val 和 Leu-Ile 的疏水柱相反。