Berl V, Huc I, Khoury R G, Krische M J, Lehn J M
Laboratoire de Chimie Supramoléculaire, ISIS, Université Louis Pasteur, Strasbourg, France.
Nature. 2000 Oct 12;407(6805):720-3. doi: 10.1038/35037545.
Synthetic single-helical conformations are quite common, but the formation of double helices based on recognition between the two constituent strands is relatively rare. Known examples include duplex formation through base-pair-specific hydrogen bonding and stacking, as found in nucleic acids and their analogues, and polypeptides composed of amino acids with alternating L and D configurations. Some synthetic polymers and self-assembled fibres have double-helical winding induced by van der Waals interactions. A third mode of non-covalent interaction, coordination of organic ligands to metal ions, can give rise to double, triple and quadruple helices, although in this case the assembly is driven by the coordination geometry of the metal and the structure of the ligands, rather than by direct inter-strand complementarity. Here we describe a family of oligomeric molecules with bent conformations, which exhibit dynamic exchange between single and double molecular helices in solution, through spiral sliding of the synthetic oligomer strands. The bent conformations leading to the helical shape of the molecules result from intramolecular hydrogen bonding within 2'-pyridyl-2-pyridinecarboxamide units, with extensive intermolecular aromatic stacking stabilizing the double-stranded helices that form through dimerization.
合成单螺旋构象相当常见，但基于两条组成链之间的识别形成双螺旋相对较少见。已知的例子包括通过碱基对特异性氢键和堆积形成双链体，如在核酸及其类似物中所见，以及由具有交替L和D构型的氨基酸组成的多肽。一些合成聚合物和自组装纤维具有由范德华相互作用诱导的双螺旋缠绕。非共价相互作用的第三种模式，即有机配体与金属离子的配位，可以产生双螺旋、三螺旋和四螺旋，尽管在这种情况下，组装是由金属的配位几何结构和配体的结构驱动的，而不是由链间直接互补性驱动的。在这里，我们描述了一类具有弯曲构象的寡聚分子，它们在溶液中通过合成寡聚物链的螺旋滑动，在单分子螺旋和双分子螺旋之间表现出动态交换。导致分子呈螺旋形状的弯曲构象是由2'-吡啶基-2-吡啶甲酰胺单元内的分子内氢键形成的，广泛的分子间芳香堆积稳定了通过二聚化形成的双链螺旋。
