Niemeyer, C.M.

Chem. - Asian J. 2009, 4, 1064-1069, 10.1002/asia.200900082

A hybrid myoglobin, containing a single‐stranded DNA anchor and a redox‐active ruthenium moiety tethered to the heme center can be used as a photocatalyst. The catalyst can be selectively immobilized on a surface‐bound complementary DNA molecule and thus readily recycled from complex reaction mixtures. This principle may be applied to a range of heme‐dependent enzymes allowing the generation of novel light‐triggered photocatalysts. Photoactivatable myoglobin containing a DNA oligonucleotide as a structural anchor was designed by using the reconstitution of artificial heme moieties containing Ru3+ ions. This semisynthetic DNA–enzyme conjugate was successfully used for the oxidation of peroxidase substrates by using visible light instead of H2O2 for the activation. The DNA anchor was utilized for the immobilization of the enzyme on the surface of magnetic microbeads. Enzyme activity measurements not only indicated undisturbed biofunctionality of the tethered DNA but also enabled magnetic separation‐based enrichment and recycling of the photoactivatable biocatalyst.

Fruk, L.; Niemeyer, C.M.

Croat. Chem. Acta 2011, 84, 269-275, 10.5562/cca1828

A bimetallic heme-DNA cofactor, containing an iron and a copper center, was synthesized for the design of novel hybrid catalysts for stereoselective synthesis. The cofactor was used for the reconstitution of apo-myoglobin. Both the cofactor alone and its myoglobin adduct were used to catalyze a model Diels Alder reaction. Stereoselectivity of this conversion was analyzed by chiral HPLC. Reactions carried out in the presence of myoglobin-heme-Cu-DNA catalyst showed greater product conversion and stereoselectivity than those carried out with the heme-Cu-DNA cofactor. This observation suggested that the protein shell plays a significant role in the catalytic conversion.