Ishizawa Seiya, Tumurkhuu Munkhtuya, Gross Elizabeth J, Ohata Jun
Department of Chemistry, North Carolina State University Raleigh NC 27695 USA
Chem Sci. 2022 Jan 20;13(6):1780-1788. doi: 10.1039/d1sc05204g. eCollection 2022 Feb 9.
Development of multiple chemical tools for deoxyribonucleic acid (DNA) labeling has facilitated wide use of their functionalized conjugates, but significant practical and methodological challenges remain to achievement of site-specific chemical modification of the biomacromolecule. As covalent labeling processes are more challenging in aqueous solution, use of nonaqueous, biomolecule-compatible solvents such as an ionic liquid consisting of a salt with organic molecule architecture, could be remarkably helpful in this connection. Herein, we demonstrate site-specific chemical modification of unprotected DNAs through a tetrazene-forming amine-azide coupling reaction using an ionic liquid. This ionic liquid-enhanced reaction process has good functional group tolerance and precise chemoselectivity, and enables incorporation of various useful functionalities such as biotin, cholesterol, and fluorophores. A site-specifically labeled oligonucleotide, or aptamer interacting with a growth factor receptor (Her2) was successfully used in the fluorescence imaging of breast cancer cell lines. The non-traditional medium-promoted labeling strategy described here provides an alternative design paradigm for future development of chemical tools for applications involving DNA functionalization.
多种用于脱氧核糖核酸（DNA）标记的化学工具的开发促进了其功能化缀合物的广泛应用，但在实现生物大分子的位点特异性化学修饰方面，仍存在重大的实际和方法学挑战。由于共价标记过程在水溶液中更具挑战性，因此使用非水的、与生物分子兼容的溶剂，如由具有有机分子结构的盐组成的离子液体，在这方面可能会非常有帮助。在此，我们展示了通过使用离子液体的四氮烯形成胺-叠氮偶联反应对未保护的DNA进行位点特异性化学修饰。这种离子液体增强的反应过程具有良好的官能团耐受性和精确的化学选择性，并能够引入各种有用的功能基团，如生物素、胆固醇和荧光团。一个位点特异性标记的寡核苷酸或与生长因子受体（Her2）相互作用的适体成功用于乳腺癌细胞系的荧光成像。这里描述的非传统介质促进的标记策略为涉及DNA功能化应用的化学工具的未来开发提供了一种替代设计范式。
