Zn2+-Ligation DNAzyme-Driven Enzymatic and Nonenzymatic Cascades for the Amplified Detection of DNA
详细信息 查看全文
- 作者：Chun-Hua Lu ; Fuan Wang ; Itamar Willner
- 刊名：The Journal of the American Chemical Society
- 出版年：2012
- 出版时间：June 27, 2012
- 年：2012
- 卷：134
- 期：25
- 页码：10651-10658
- 全文大小：432K
- 年卷期：v.134,no.25(June 27, 2012)
- ISSN：1520-5126
文摘
A generic fluorescence sensing platform for analyzing DNA by the Zn2+-dependent ligation DNAzyme as amplifying biocatalyst is presented. The platform is based on the target DNA induced ligation of two substrate subunits and the subsequent opening of a beacon hairpin probe by the ligated product. The strand displacement of the ligated product by the beacon hairpin is, however, of limited efficiency. Two strategies are implemented to overcome this limitation. By one method, a 鈥渉elper鈥?nucleic acid sequence is introduced into the system, and this hybridizes with the DNAzyme components and releases the ligated product for opening of the hairpin. By the second method, a nicking enzyme (Nt.BspQI) is added to the system, and this nicks the duplex between the beacon and ligated product while recycling the free ligation product. By combining the two coadded components (鈥渉elper鈥?sequence and nicking enzyme), the sensitive detection of the analyte is demonstrated (detection limit, 20 pM). The enzyme-free amplified fluorescence detection of the target DNA is further presented by the Zn2+-dependent ligation DNAzyme-driven activation of the Mg2+-dependent DNAzyme. According to this method, the Mg2+-dependent DNAzyme subunits displace the ligated product, and the resulting assembled DNAzyme cleaves a fluorophore/quencher-modified substrate to yield fluorescence. The method enabled the detection of the target DNA with a detection limit corresponding to 10 pM. The different sensing platforms are implemented to detect the Tay鈥揝achs genetic disorder mutant.