Structure, characterisation and application of an unspecific peroxygenase from Daldinia childiae

Unspecific peroxygenases (UPOs) have emerged as useful biocatalysts for the scalable and selective oxygenation of a large variety of organic molecules. UPOs have been divided into family I and family II enzymes, dependent upon sequence similarity and molecular weight, with family I being shorter in sequence. Here we report the characterisation and application of the family I UPO from Daldinia childiae (DchUPO). The enzyme was expressed in both Escherichia coli and Komagataella phaffii, yielding protein for kinetic and structural studies and biocatalytic application respectively. The structure of the enzyme revealed notable differences in the active site tunnel, compared with the well-studied family I artUPO, including F79 for V69 and F171 for I160. Notably, these differences were manifested in selectivity divergent from other UPOs when DchUPO was applied to preparative biotransformations; for example, (-)-menthol was converted exclusively into cis-6-hydroxymenthol in contrast to artUPO, which gave exclusively the tertiary alcohol 2,8-menthanediol.