Molecular determinants for selective C25-hydroxylation of vitamins D2 and D3 by fungal peroxygenases

Abstract

Selective oxygenations of aliphatic compounds are among the most challenging reactions in organic chemistry for the regio and/or stereo specific synthesis of pharmaceuticals and fine chemicals. Recently, a new peroxidase type, which shares the active-site architecture and reaction mechanism of cytochromes P450, but has the advantage of being activated directly by H2O2, was isolated from Agrocybe aegerita (Ullrich, 2004), and later identified in a variety of sequenced basidiomycete genomes, including that of Coprinopsis cinerea (Floudas, 2012). The A. aegerita heme-thiolate (HTP) enzyme has been the most widely investigated basidiomycete peroxygenase, and recent studies have shown that the C. cinerea enzyme has comparative advantages related to its high conversion yield/selectivity for some hydroxylation reactions, and its production as a recombinant protein in an industrial expression host (Babot, 2013; 2014). 25-monohydroxylated vitamin D3 (cholecalciferol) and D2 (ergocalciferol), compounds of high interest in human health and animal feeding, can be obtained through reaction with both A. aegerita and C. cinerea enzymes. In the present study, PELE computational analyses are used to rationalize the underlying mechanisms responsible for differences in reactivity and selectivity observed experimentally between both enzymes (Lucas, 2015). References Babot, E. D., et al., Biotechnol. Bioeng., (2013), 110, 2332. Babot, E. D., et al., Chemcatchem, (2014), online. Floudas, D., et al. Science, (2012), 336, 1715-1719. Lucas, F., et al. Catal. Sci. Tech., (2015), online. Ullrich, R., et al., Appl. Environ. Microbiol. (2004), 70, 4575-4581.