College of Life Science, Yangtze University, 266 Jingmi Road, Jingzhou, Hubei, 434025, China.
Department of Chemistry, Waterloo Institute for Nanotechnology, University of Waterloo, Waterloo, Ontario, N2 L 3G1, Canada.
Chembiochem. 2020 Aug 17;21(16):2259-2263. doi: 10.1002/cbic.202000073. Epub 2020 May 5.
We herein report a DNAzyme named T30695 (sequence: (G T) ) that can catalyze Zn insertion into three different porphyrins in the presence of Pb as a cofactor. Meanwhile, T30695 with Pb alone was found to cause a shift in both the fluorescence and UV-vis spectra of protoporphyrin IX (PPIX), thus suggesting that metalation of Pb was also achieved at room temperature. From kinetic measurements, the reaction required two Pb ions; this is consistent with one being a cofactor and the other being a substrate. No previous reports inserted Pb into porphyrins by using DNAzymes or protein-based enzymes. This reaction was most significantly inhibited in the presence of K followed by Na and Li , suggesting the importance of the Pb -stabilized G-quadruplex. When Pb is inserted into PPIX, its emission blue shifts from 635 to 590 nm, thus allowing simple ratiometric fluorescent sensing with a detection limit of 1.2 nM Pb .
我们在此报告一种名为 T30695 的 DNA 酶（序列为：（G T）），它可以在 Pb 作为辅助因子的存在下催化 Zn 插入三种不同的卟啉中。同时，我们发现单独的 T30695 与 Pb 一起会导致原卟啉 IX（PPIX）的荧光和 UV-vis 光谱发生位移，这表明 Pb 的金属化也可以在室温下实现。从动力学测量来看，反应需要两个 Pb 离子；这与一个作为辅助因子和另一个作为底物的情况一致。以前没有使用 DNA 酶或基于蛋白质的酶将 Pb 插入卟啉的报道。该反应在存在 K 后受到最显著的抑制，随后是 Na 和 Li，这表明 Pb 稳定的 G-四链体的重要性。当 Pb 插入 PPIX 时，其发射蓝移从 635nm 变为 590nm，从而可以通过简单的比率荧光传感进行检测，检测限为 1.2nM Pb。
