Wang Jin, Kaiyum Yunus A, Wang Sihan, Li Xiangmei, Lei Hongtao, Johnson Philip E, Liu Juewen
Guangdong Provincial Key Laboratory of Food Quality and Safety, College of Food Science, South China Agricultural University Guangzhou 510642 China.
Department of Chemistry, Waterloo Institute for Nanotechnology, University of Waterloo Waterloo Ontario N2L 3G1 Canada
Chem Sci. 2025 Jun 24. doi: 10.1039/d5sc02436f.
Using both Co and Ni as target metal ions, aptamer selections were carried out by immobilization of a DNA library hybridization. A set of aptamers were obtained although they all showed binding to both metal ions. The Co-1 aptamer was highly enriched in both selections and it is a general metal binding aptamer with binding affinity following the Irving-Williams series: Mn < Fe < Co < Ni < Cu > Zn. Using NMR spectroscopy, Co-1 forms new base pairs with a relatively large structural change upon binding to Zn, whereas a previously reported Zn-1 aptamer shows less conformational change and rigidifies upon Zn binding. The induced-fitting of the Co-1 aptamer and the lock-and-key binding of the Zn-1 aptamer may explain the general metal binding of the former. Using isothermal titration calorimetry, Co-1 binding Co was an enthalpy-driven event and the was determined to be 2.7 μM, whereas the from the strand-displacement assay was 76 nM. The Co-1 aptamer is the first reported aptamer to follow the Irving-Williams series, although this series is very prevalent in proteins. This aptamer can thus serve as a model system for understanding metal binding by DNA and can also be a general first-row transition metal sensing element.
以钴（Co）和镍（Ni）作为目标金属离子，通过固定化DNA文库杂交进行适配体筛选。尽管获得的一组适配体均显示出对两种金属离子的结合，但钴-1适配体在两次筛选中均高度富集，它是一种通用的金属结合适配体，其结合亲和力符合欧文-威廉姆斯序列：锰（Mn）＜铁（Fe）＜钴（Co）＜镍（Ni）＜铜（Cu）＞锌（Zn）。利用核磁共振光谱法，钴-1在与锌结合时形成了具有相对较大结构变化的新碱基对，而先前报道的锌-1适配体在锌结合时构象变化较小且变得更刚性。钴-1适配体的诱导契合和锌-1适配体的锁钥结合可能解释了前者的通用金属结合特性。采用等温滴定量热法，钴-1与钴的结合是一个焓驱动的过程，解离常数被测定为2.7 μM，而通过链置换分析得到的解离常数为76 nM。钴-1适配体是首个被报道的遵循欧文-威廉姆斯序列的适配体，尽管该序列在蛋白质中非常普遍。因此，这种适配体可作为理解DNA与金属结合的模型系统，也可作为一种通用的第一行过渡金属传感元件。
