Surface-immobilized DNAzyme-type biocatalysis.
The structure of the double helix of deoxyribonucleic acid (DNA, also called duplex-DNA) was elucidated sixty years ago by Watson, Crick, Wilkins and Franklin. Since then, DNA has continued to hold a fascination for researchers in diverse fields including medicine and nanobiotechnology. Nature has indeed excelled in diversifying the use of DNA: beyond its canonical role of repository of genetic information, DNA could also act as a nanofactory able to perform some complex catalytic tasks in an enzyme-mimicking manner. The catalytic capability of DNA was termed DNAzyme; in this context, a peculiar DNA structure, a quadruple helix also named quadruplex-DNA, has recently garnered considerable interest since its autonomous catalytic proficiency relies on its higher-order folding that makes it suitable to interact efficiently with hemin, a natural cofactor of many enzymes. Quadruplexes have thus been widely studied for their hemoprotein-like properties, chiefly peroxidase-like activity, i.e., their ability to perform hemin-mediated catalytic oxidation reactions. Recent literature is replete with applications of quadruplex-based peroxidase-mimicking DNAzyme systems. Herein, we take a further leap along the road to biochemical applications, assessing the actual efficiency of catalytic quadruplexes for the detection of picomolar levels of surface-bound analytes in an enzyme-linked immunosorbent (ELISA)-type assay. To this end, we exploit an innovative strategy based on the functionalization of DNA by a multitasking platform named RAFT (for regioselectivity addressable functionalized template), whose versatility enables the grafting of DNA whatever its nature (duplex-DNA, quadruplex-DNA, etc.). We demonstrate that the resulting biotinylated RAFT/quadruplex systems indeed acquire catalytic properties that allow for efficient luminescent detection of picomoles of surface-bound streptavidin. We also highlight some of the pitfalls that have to be faced during optimization, notably demonstrating that highly optimized experimental conditions can make DNA pre-catalysts catalytically competent whatever their secondary structures.
Institut de Chimie Moléculaire, Université de Bourgogne (ICMUB), CNRS UMR6302, Dijon, France. david.monchaud@u-bourgogne.fr.
Loic
L
Stefan
Thomas
T
Lavergne
Nicolas
N
Spinelli
Eric
E
Defrancq
David
D
Monchaud
D055162:Biocatalysis; D021881:DNA, Catalytic / Q000737:chemistry / Q000378:metabolism*; D054856:G-Quadruplexes; D061925:Immobilized Nucleic Acids / Q000737:chemistry / Q000378:metabolism; D010084:Oxidation-Reduction; D010544:Peroxidases / Q000737:chemistry / Q000378:metabolism; D013499:Surface Properties
D021881:DNA, Catalytic; D061925:Immobilized Nucleic Acids; D010544:Peroxidases