Label-free fluorescence assay for rapid detection of RNase H activity based on Tb3+-induced G-quadruplex conjugates

Abstract

Ribonuclease H (RNase H), a highly conserved damage-repair protein, hydrolyzes RNA in the DNA:RNA hybrid duplex and breaks RNA/DNA junctions. In this study, we demonstrated a unique Tb³⁺-based fluorescence assay that is low cost, facile, and label-free for assaying RNase H activity and inhibitions by using a G-quadruplex formation strategy. This novel assay method can detect RNase H at the lowest detection limit of 2 U mL⁻¹ under optimal conditions. We demonstrated the utility of the assay by antibiotics screening and identified ethidium bromide (EB) and Gentamycin as RNase H inhibitors. This approach demonstrated that Tb³⁺ could be used as a functional tool in specific fields in the future.