适体
次黄嘌呤
尿酸
等温滴定量热法
化学
生物化学
黄嘌呤
Rasburicase酶
组合化学
指数富集配体系统进化
酶
分子生物学
生物
核糖核酸
高尿酸血症
基因
出处
期刊:ChemBioChem
[Wiley]
日期:2022-12-07
卷期号:24 (2)
被引量:5
标识
DOI:10.1002/cbic.202200564
摘要
Uric acid is the end-product of purine metabolism in humans and an important biomarker for many diseases. To achieve the detection of uric acid without using enzymes, we previously selected a DNA aptamer for uric acid with a Kd of 1 μM but the aptamer required multiple Na+ ions for binding. Saturated binding was achieved with around 700 mM Na+ and the binding at the physiological condition was much weaker. In this work, a new selection was performed by alternating Mg2+ -containing buffers with Na+ and Li+ . After 13 rounds of selection, a new aptamer sequence named UA-Mg-1 was obtained. Isothermal titration calorimetry confirmed aptamer binding in both selection buffers, and the Kd was around 8 μM. The binding of UA-Mg-1 to UA required only Mg2+ . This is an indicator of successful switching of metal dependency via the salt-toggled selection method. The UA-Mg-1 aptamer was engineered into a fluorescent biosensor based on the strand-displacement assay with a limit of detection of 0.5 μM uric acid in the selection buffer. Finally, comparison with the previously reported Na+ -dependent aptamer and a xanthine/uric acid riboswitch was also made.
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