Specific loop modifications of the thrombin-binding aptamer trigger the formation of parallel structures
Specific loop modifications of the thrombin-binding aptamer trigger the formation of parallel structures
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DOI：
10.1111/febs.12670
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发表时间：
2014-02-01
期刊：
影响因子：
5.4
通讯作者：
Eritja, Ramon
中科院分区：
文献类型：
--
作者：
Avino, Anna;Portella, Guillem;Eritja, Ramon
富含鸟嘌呤的序列显示出很大的结构变异性，折叠范围从双螺旋到三螺旋和四螺旋。四链体是多态性的，可以显示多种化学计量、平行和反平行链排列以及不同的拓扑排列。我们在此分析了凝血酶结合适体 (TBA) 序列中分子内反平行和分子间平行 G 四链体之间的平衡。我们的理论和实验研究表明，TBA 环上的一个明显简单的修饰会引起 TBA 单体反平行结构的巨大变化，产生平行的 G-四联体，显示出新的 T-四分体。目前的结果说明了 G-四链体的极端多态性以及它们在溶液中的构象可以通过核苷酸修饰轻松操纵。
Guanine‐rich sequences show large structural variability, with folds ranging from duplex to triplex and quadruplex helices. Quadruplexes are polymorphic, and can show multiple stoichiometries, parallel and antiparallel strand alignments, and different topological arrangements. We analyze here the equilibrium between intramolecular antiparallel and intermolecular parallel G‐quadruplexes in the thrombin‐binding aptamer (TBA) sequence. Our theoretical and experimental studies demonstrate that an apparently simple modification at the loops of TBA induces a large change in the monomeric antiparallel structure of TBA to yield a parallel G‐quadruplex showing a novel T‐tetrad. The present results illustrate the extreme polymorphism of G‐quadruplexes and the ease with which their conformation in solution can be manipulated by nucleotide modification.