Kähkölä Heidi, Herath Muditha, Virta Pasi, Lönnberg Tuomas
Department of Chemistry, University of Turku, Henrikinkatu 2, 20500 Turku, Finland.
Org Biomol Chem. 2025 Feb 12;23(7):1714-1722. doi: 10.1039/d4ob01973c.
In this article, a neoacetalization-based method for post-SELEX modification of aptamers is introduced. Three modified quinine binding aptamer scaffolds were synthesized by replacing three different nucleosides of the binding site with a (2,3)-4-(methoxyamino)butane-1,2,3-triol residue. These aptamer scaffolds were incubated in different aldehyde mixtures with and without quinine, allowing the reversible formation of -methoxy-1,3-oxazinane (MOANA) nucleoside analogues through dynamic combinatorial chemistry. UHPLC-MS analysis identified two aldehydes, namely methyl 4-formylbenzoate and 3-nitrobenzaldehyde, with significantly different tendency to react with one of the aptamer scaffolds in the presence and absence of quinine. The quinine binding affinity of these two modified aptamers was determined by isothermal titration calorimetry (ITC). Unexpectedly, the 3-nitrobenzaldehyde derivatized aptamer dimerized on binding quinine at the relatively high concentration of the ITC. In addition, we discovered that with another modified aptamer, quinine binding caused cleavage of the N-O bond of the (2,3)-4-(methoxyamino)butane-1,2,3-triol residue.
在本文中，介绍了一种基于新缩醛化反应的适体SELEX后修饰方法。通过用(2,3)-4-(甲氧基氨基)丁烷-1,2,3-三醇残基取代结合位点的三种不同核苷，合成了三种修饰的奎宁结合适体支架。将这些适体支架在含有和不含奎宁的不同醛混合物中孵育，通过动态组合化学实现 -甲氧基-1,3-恶嗪烷（MOANA）核苷类似物的可逆形成。超高效液相色谱-质谱分析确定了两种醛，即4-甲酰基苯甲酸甲酯和3-硝基苯甲醛，在有和没有奎宁存在的情况下，它们与其中一种适体支架反应的倾向有显著差异。通过等温滴定量热法（ITC）测定了这两种修饰适体与奎宁的结合亲和力。出乎意料的是，在ITC相对较高浓度下，3-硝基苯甲醛衍生的适体在与奎宁结合时发生二聚化。此外，我们发现对于另一种修饰适体，奎宁结合导致(2,3)-4-(甲氧基氨基)丁烷-1,2,3-三醇残基的N-O键断裂。
