Functional-Group Specific Aptamers Indirectly Recognizing Compounds with Alkyl Amino Group

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• 作者：Hongcheng Mei ; Tao Bing ; Xiaojuan Yang ; Cui Qi ; Tianjun Chang ; Xiangjun Liu ; Zehui Cao ; Dihua Shangguan
• 刊名：Analytical Chemistry
• 出版年：2012
• 出版时间：September 4, 2012
• 年：2012
• 卷：84
• 期：17
• 页码：7323-7329
• 全文大小：433K
• 年卷期：v.84,no.17(September 4, 2012)
• ISSN：1520-6882

文摘

Aptamers are usually generated against a specific molecule. Their high selectivity makes them only suitable for studying specific targets. Since it is nearly impossible to generate aptamers for every molecule, it can be of great interest to select aptamers recognizing a common feature of a group of molecules in many applications. In this paper, we describe the selection of aptamers for indirect recognition of alkyl amino groups. Because amino groups are small and positive charged, we introduced a protection group, p-nitrobenzene sulfonyl (p-nosyl) to convert them into a form suitable for aptamer selection. Taking N^蔚-p-nosyl-l-lysine (PSL) as a target, we obtained a group of aptamers using the SELEX technique. Two optimized aptamers, M6b-M14 and M13a exhibit strong affinity to PSL with the K_d values in the range of 2鈥? 渭M. They also show strong affinity to other compounds containing p-nosyl-protected amino groups except those also possessing an 伪-carboxyl group. Both aptamers adopt an antiparallel G-quadruplex structure when binding to targets. An aptamer beacon based on M6b-M14 showed good selectivity toward the reaction mixture of p-nosyl-Cl and alkyl amino compounds, and could recognize lysine from amino acid mixtures indirectly, suggesting that aptamers against a common moiety of a certain type of molecules can potentially lead to many new applications. Through this study, we have demonstrated the ability to select aptamers for a specific part of an organic compound, and the chemical conversion approach may prove to be valuable for aptamer selection against molecules that are generally difficult for SELEX.