Hemin-utilizing G-quadruplex DNAzymes are strongly active in organic co-solvents

• Published in: Biochimica et biophysica acta. General subjects Vol. 1861; no. 5; pp. 1455 - 1462
• Main Authors: Canale, Thomas D., Sen, Dipankar
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.05.2017
• Subjects: Binding Sites; Catalysis; catalysts; catalytic activity; Circular Dichroism; dimethylformamide; Dimethylformamide - chemistry; DNA; DNA, Catalytic - chemistry; DNA, Catalytic - metabolism; DNAzyme; Enzyme Activation; enzyme activity; Formamides - chemistry; G-quadruplex; G-Quadruplexes; Guanosine - chemistry; Guanosine - metabolism; Heme; Hemin - chemistry; Hemin - metabolism; iron; Ligands; methanol; Methanol - chemistry; Oligonucleotides - chemistry; Oligonucleotides - metabolism; Organic Chemicals - chemistry; Organic solvents; Oxidation; Oxidation-Reduction; peroxidase; Protein Binding; solvents; Solvents - chemistry; Spectrophotometry, Ultraviolet; Structure-Activity Relationship; tert-Butyl Alcohol - chemistry; Water - chemistry; DNAzyme; Oxidation; Organic solvents; G-quadruplex; Heme
• ISSN: 0304-4165; 1872-8006
• DOI: 10.1016/j.bbagen.2016.11.019

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. This article is part of a Special Issue entitled “G-quadruplex” Guest Editor: Dr. Concetta Giancola and Dr. Daniela Montesarchio. •Hemin-binding DNA and RNA G-quadruplexes are oxidative enzymes.•Such “heme-DNAzymes” are catalytically active in high percentages of protic co-solvents.•This activity in cosolvents such as methanol and formamide augurs their utility in green chemistry.