Colorimetric Detection of S1 Nuclease Activity using a Hairpin DNA with Split G-Quadruplex

Abstract

Hairpin DNA containing split G-quadruplex at its terminus displayed tagging position-dependent horseradish peroxidase activity. In general, the hairpin DNA coupled with one GGG repeat at its 5’-terminus and three GGG repeats at its 3′-terminus demonstrated strong catalytic activity, while slight activity was observed after exchanging the position of split G-quadruplex sequence. Inspired by these observations, a novel colorimetric biosensor for nuclease activity assay was developed by selecting S1 nuclease as the model. Specifically, S1 nuclease cleaves the split G-quadruplex into mono- or oligonucleotide fragments, thereby suppressing the catalytic activity, accompanied by a color change from blue to colorless. Under optimum conditions, S1 nuclease was determined with a linear range from 1.60 to 17.6 U/mL and a detection limit of 1.458 U/mL. The constructed method was simple and did not require complex sequence design, expensive instrumentation, and probe labeling. Most importantly, this work facilitates a better understanding of the catalytic mechanism of the DNAzyme and provides an example of the practical application of G-quadruplex-based DNAzyme.

Keywords:

• DNAzyme
• Hairpin DNA
• S1 nuclease
• split G-quadruplex

Disclosure statement

No potential competing interests are reported by the authors.

Additional information

Funding

We gratefully acknowledge the financial support from the Scientific and Technological Project of Henan Province (202102110111, 222102110335), the Young Backbone Teachers Fund of Henan (2021GGJS123), the Open Funding Project of Henan Key Laboratory of Industrial Microbial Resources and Fermentation Technology (Nanyang Institute of Technology) (HIMFT20190310), and the Cultivation Fund of the National Natural Science Foundation of Nanyang Normal University (2022PY007).