Fig. 5: Catalytic function and mutants of CcOMT1.

a Methylation of natsudaidain (1) catalyzed by CcOMT1. b Total ion current chromatograms for the enzymatic reactions. The reaction mixtures were incubated at 50 °C for 4 h. c Tandem mass spectra of product 1a. d Structure model of CcOMT1. SAM and natsudaidain are shown in magenta and green, respectively. e Molecular docking with natsudaidain into the substrate binding pocket of CcOMT1. f Relative activities of alanine-substituted mutants of CcOMT1. g Effects of different mutants on enzyme reactivity. The error bars represents the standard deviation from three replicates.