Herein, an integrated and restructive probe mediated strand displacement amplification (SDA) strategy is developed for sensitive and specific DNA MTase activity detection. The probe is specially designed with a hairpin structure, which encloses the MTase recognition site in the stem and seals the SDA primer and template in the loop. Under the action of DNA MTase, the probe is methylated and cleaved by DpnI endonuclease, causing its stem truncated. The truncated structure then reconstructs with a shrunken loop and a partially-hybridized duplex of stem, drawing the SDA primer and template domains close to trigger cascade amplification. Numerous G-quadruplexes are produced and intercalated by N-methyl-mesoporphyrin IX (NMM) to generate enhanced fluorescent signal. This strategy detects MTase activity down to 0.063 U/mL, and well distinguishes Dam MTase from its analogues. It is further applied for the MTase detection in biological samples and MTase inhibition analysis. The strategy will provide a promising tool for detection MTase activity in biomedical study and early cancer diagnosis.

在本文中，开发了一种整合的重组探针介导的链置换扩增（SDA）策略，用于敏感和特异的DNA MTase活性检测。该探针经过特殊设计，具有发夹结构，该结构将茎中的MTase识别位点封闭，并将SDA引物和模板密封在环中。在DNA MTase的作用下，探针被甲基化并被DpnI核酸内切酶切割，导致其茎被截断。截短的结构然后以收缩的环和茎的部分杂交双链体重建，将SDA引物和模板结构域拉近以触发级联扩增。N产生并插入了许多G四链体-甲基间卟啉IX（NMM）产生增强的荧光信号。该策略可检测低至0.063 U / mL的MTase活性，并能将Dam MTase与类似物区分开。它进一步用于生物样品中的MTase检测和MTase抑制分析。该策略将为在生物医学研究和早期癌症诊断中检测MTase活性提供有希望的工具。