Exonuclease III-assisted strand displacement reaction-driven cyclic generation of G-quadruplex strategy for homogeneous fluorescent detection of melamine.

Exonuclease III-assisted strand displacement reaction-driven cyclic generation of G-quadruplex strategy for homogeneous fluorescent detection of melamine.
Talanta. 2019 Oct 01;203:255-260
Authors: Chen P, Huang K, Zhang P, Sawyer E, Wu Z, Wei X, Ying B, Geng J
Abstract
Development of flexible, sensitive, selective and simple melamine detection is in high demand and of great significance. Here, we proposed a homogeneous turn-off mode fluorescent strategy to detect melamine by coupling the process of exonuclease III-assisted (Exo III) amplification with the strand displacement reaction (SDR)-driven assembly of DNA G-quadruplex structures. Melamine (M) could bind to the thymine (T) base through hydrogen bonding to form a T-M-T structure, which inhibits the subsequent nucleic acid amplification reaction and formation of the G-quadruplex structure. DNA strand (G1) served as both a recognition probe and a signal probe, thus greatly simplifying the experimental design and operation. Furthermore, to improve the detection sensitivity, an ingeniously designed segment of double-stranded DNA (dsDNA, P1-G2) that contained the G-quadruplex sequence (G2) and a partially hybridized signal trigger strand (P1) was added to the system. Following the SDR and Exo III-assisted amplification, G1-DNA and G2-DNA were released and the cyclic production of G-quadruplex structures was initiated. The generated DNA G-quadruplex bound to the NMM (a fluorescent dye...

Source: Talanta - June 17, 2019 Category: Chemistry Authors: Chen P, Huang K, Zhang P, Sawyer E, Wu Z, Wei X, Ying B, Geng J Tags: Talanta Source Type: research