Fig. 1

Illustrations of methods to identify the desired methyltransferases activities. a Genomic and chemical screening methods are used to identify the novel methyltransferases from native microbial hosts. First, genome sequencing is carried out to obtain the genetic information. Second, in silico tools are used to identify the putative methyltransferase gene. For natural product biosynthesis, such methyltransferases are often found in a biosynthetic gene cluster in microbial hosts. Third, mutant strains with knock-out (KO) or knock-in (KI) to delete or overexpress the putative methyltransferases gene, respectively, are constructed. Finally, chemical screening is then carried out to profile the non-methylated intermediates or elevated methylated products from these mutant strains as compared to wildtype (WT) strain. Some illustrations were created with BioRender.com. b Promiscuous methyltransferases are used to catalyze structurally similar substrates to achieve the desired methylation reaction. The 3D model is caffeate O-methyltransferase from Homo sapiens (PDB: 3BWY). The bound SAH is shown in green