Molecular mechanism of helicase on graphene-based hybridization reaction platform for microRNA detection

Abstract

In this study, Escherichia coli RecQ helicase (RecQE) was introduced for the first time to demonstrate its molecular mechanism on a hybridization reaction for detecting microRNA (miRNA), using graphene oxide as a nano-quencher. In the miRNA detection system, the annealing of a “blocking” DNA strand to a fluorophore-labeled DNA probe (FDNA) effectively interfered with the non-specific binding of RecQE with FDNA. Aided by the motor force driven by adenosine triphosphate, the helicase-assisted hybridization system enhanced the hybridization of FDNA and miRNA, besides separating them. Compared with non-enzymatic detection system, the fluorescence signal of the RecQE-assisted system was increased by 17.17%. More interestingly, RecQE did not affect stability of the formed FDNA–RNA duplex. This study will greatly benefit further studies of biological sensing processes based on nucleic acid hybridization in living cells, and has great enlightening significance for designing and improving miRNA detection methods by using recombinant helicases.