H-Bond Self-Assembly: Folding versus Duplex Formation.
H-Bond Self-Assembly: Folding versus Duplex Formation.
复制标题
DOI：
10.1021/jacs.7b01357
复制
发表时间：
2017-05-17
影响因子：
15
通讯作者：
Hunter CA
中科院分区：
文献类型：
--
作者：
Núñez-Villanueva D;Iadevaia G;Stross AE;Jinks MA;Swain JA;Hunter CA
具有互补氢键供体(D)和受体(A)位的线性低聚物可以通过分子间氢键相互作用形成双链或通过分子内氢键折叠。这些相互竞争的平衡已经通过核磁共振滴定和稀释实验对具有不同识别位点和骨架的七个系统进行了量化。对于所有七种结构，均观察到同源序列2-MERS(AA·DD)形成双链，其中不存在竞争折叠平衡。相应的杂序列AD2-MERS也形成了双链，但观察到的自缔合常数受到单体折叠平衡的强烈影响。当主链是柔性的(五个或更多可旋转的键分隔识别位置)时，分子内氢键更有利，折叠状态高度填充。对于这些系统，AD·AD双工的稳定性比相应的AA·DD双工的稳定性低1-2个数量级。然而，对于三个具有更多刚性骨架(少于5个可旋转键)的结构，没有观察到分子内相互作用，折叠不会与双链形成竞争。这些系统是开发更长的、显示序列选择性双链形成的混合序列合成信息分子的有希望的候选者。
Linear oligomers equipped with complementary H-bond donor (D) and acceptor (A) sites can interact via intermolecular H-bonds to form duplexes or fold via intramolecular H-bonds. These competing equilibria have been quantified using NMR titration and dilution experiments for seven systems featuring different recognition sites and backbones. For all seven architectures, duplex formation is observed for homo-sequence 2-mers (AA·DD) where there are no competing folding equilibria. The corresponding hetero-sequence AD 2-mers also form duplexes, but the observed self-association constants are strongly affected by folding equilibria in the monomeric states. When the backbone is flexible (five or more rotatable bonds separating the recognition sites), intramolecular H-bonding is favored, and the folded state is highly populated. For these systems, the stability of the AD·AD duplex is 1–2 orders of magnitude lower than that of the corresponding AA·DD duplex. However, for three architectures which have more rigid backbones (fewer than five rotatable bonds), intramolecular interactions are not observed, and folding does not compete with duplex formation. These systems are promising candidates for the development of longer, mixed-sequence synthetic information molecules that show sequence-selective duplex formation.