Helmholtz Centre for Environmental Research (UFZ), Permoserstraße 15, 04318 Leipzig, Germany.
J Anal Methods Chem. 2012;2012:415697. doi: 10.1155/2012/415697. Epub 2012 Dec 30.
Small organic molecules are challenging targets for an aptamer selection using the SELEX technology (SELEX-Systematic Evolution of Ligans by EXponential enrichment). Often they are not suitable for immobilization on solid surfaces, which is a common procedure in known aptamer selection methods. The Capture-SELEX procedure allows the selection of DNA aptamers for solute targets. A special SELEX library was constructed with the aim to immobilize this library on magnetic beads or other surfaces. For this purpose a docking sequence was incorporated into the random region of the library enabling hybridization to a complementary oligo fixed on magnetic beads. Oligonucleotides of the library which exhibit high affinity to the target and a secondary structure fitting to the target are released from the beads for binding to the target during the aptamer selection process. The oligonucleotides of these binding complexes were amplified, purified, and immobilized via the docking sequence to the magnetic beads as the starting point of the following selection round. Based on this Capture-SELEX procedure, the successful DNA aptamer selection for the aminoglycoside antibiotic kanamycin A as a small molecule target is described.
小分子是使用 SELEX 技术（指数富集的配体系统进化）进行适体选择的挑战性靶标。它们通常不适合固定在固体表面上，这是已知适体选择方法中的常见程序。Capture-SELEX 程序允许选择用于溶质靶标的 DNA 适体。构建了一个特殊的 SELEX 文库，目的是将该文库固定在磁珠或其他表面上。为此，将对接序列掺入文库的随机区域中，从而使文库与固定在磁珠上的互补寡核苷酸杂交。在适体选择过程中，从珠子上释放出与靶标具有高亲和力且二级结构与靶标匹配的文库寡核苷酸以与靶标结合。这些结合复合物的寡核苷酸被扩增、纯化，并通过对接序列固定在磁珠上，作为下一轮选择的起点。基于这种 Capture-SELEX 程序，成功地选择了小分子靶标氨基糖苷类抗生素卡那霉素 A 的 DNA 适体。
