Highly Regioselective and Stereoselective Hydroxylation of Free Amino Acids by a 2-Oxoglutarate-Dependent Dioxygenase from .

Hydroxyl amino acids have tremendous potential applications in food and pharmaceutical industries. However, available dioxygenases are limited for selective and efficient hydroxylation of free amino acids. Here, we identified a 2-oxoglutarate-dependent dioxygenase from by gene mining and characterized the encoded protein (PH1). PH1 was estimated to have a molecular weight of 29 kDa. The optimal pH and temperature for its l-proline hydroxylation activity were 6.5 and 30 °C, respectively. The and values of PH1 were 1.07 mM and 0.54 s, respectively, for this reaction by which 120 mM l-proline was converted to -4-hydroxy-l-proline with 92.8% yield (3.93 g·L·h). EDTA, [1,10-phenanthroline], Cu, Zn, Co, and Ni inhibited this reaction. PH1 was also active toward l-isoleucine for 4-hydroxyisoleucine synthesis. Additionally, the unique biophysical features of PH1 were predicted by molecular modeling whereby this study also contributes to our understanding of the catalytic mechanisms of 2-oxoglutarate-dependent dioxygenases.