Producing a recombinant flavin-containing monooxygenase from Coffea arabica in Escherichia coli for screening of potential natural substrates.

Only few biological functions have been related with flavin-containing monooxygenases (FMOs) in plants, such as specific roles in auxin biosynthesis, pathogen defense, and metabolism of glucosinolates. Biochemical characterization using recombinant proteins is a promising approach to determine the precise specificity of plant FMOs for potential natural substrates. FMOs may be very difficult to express in a soluble form due to their highly hydrophobic nature and this can be improved by fusing them to solubility-enhancing proteins, such as maltose-binding protein (MBP) and N-utilization substance A (NusA). Here we describe the expression of a recombinant FMO from Coffea arabica as a maltose-binding protein fusion in Escherichia coli and its purification by affinity chromatography, producing a ready-to-use protein for enzymatic activity assays.