Title
Hemin-utilizing G-quadruplex DNAzymes are strongly active in organic co-solvents
Author
Thomas D. Canale, Dipankar Sen
Year
2016
Journal
Biochimica et Biophysica Acta (BBA) - General Subjects
Abstract
The widespread use of organic solvents in industrial processes has focused in recent years on the utility of “green” solvents – those with less harmful environmental, health, and safety properties – such as methanol and formamide. However, protein enzymes, regarded as green catalysts, are often incompatible with organic solvents. Herein, we have explored the oxidative properties of a Fe(III)-heme, or hemin, utilizing catalytic DNA (heme·DNAzyme) in different green solvent-water mixtures. We find that the peroxidase and peroxygenase activities of the heme·DNAzyme are strongly enhanced in 20–30% v/v methanol or formamide, relative to water alone. Protic solvent content of > 30% v/v gradually diminishes heme·DNAzyme catalytic activity; however, the heme·DNAzyme is still active in as high as 80% v/v methanol. In contrast to protic solvents, aqueous dimethylformamide solutions largely inhibit heme·DNAzyme activity. In view of the strong catalytic activity of heme·DNAzyme in aqueous methanol, we were able to determine that a 60% v/v methanol-water mixture gives the most optimal yield of the dibenzothiophene sulfoxide (DBTO) oxidation product of petroleum-derived dibenzothiophene (DBT). The high product yield reflects both DNAzyme catalysis and a high substrate availability. Overall, these results emphasize the excellent promise of G-quadruplex forming DNA catalysts in application to “greener” industrial chemistry.
Instrument
J-810
Keywords
Circular dichroism, DNA structure, Chemical stability, Ligand binding, Biochemistry