Abstract
(R)-Phenylephrine [(R)-PE] is an α1-adrenergic receptor agonist widely used as a nasal decongestant and a cardiac agent without major side effects opposing to other adrenergic drugs such as ephedrine. In addition, the current mass-production procedure usually consists of (S) chiral form (50%). In an end to increase the specificity, a bio-catalytic transformation procedure using a novel short-chain dehydrogenase/reductase (SDR) from Serratia marcescens BCRC 10948 (Peng, G. J. et al.) to convert 1-(3-hydroxyphenyl)-2-(methylamino) ethanone (HPMAE) into an enantioseletive (R)-PE (more than 99%) has been attempted. However, this method performs relatively low conversion yield and productivity. In this study, we aim to determine the crystallographic structure of SmSDR as a structural basis to engineer high-activity SmSDR variants. Here, we report the 1.47 Å atomic-resolution apo-form structure. A liganded complex was built using Discovery Studio. Several mutants were predicted and characterized based on a structure-guided approach. A double mutant SmSDR-F98YF202L was found to display the highest activity. Furthermore, this mutant demonstrated a much higher conversion yield and productivity in the whole-cell assay, suggesting a valuable engineered variant for pharmaceutical applications.