O-METHYLTRANSFERASE PROTEIN WITH HIGHLY SPECIFIC CATALYTIC FUNCTION FOR MULTIPLE BIAS PARENT NUCLEI AND ENCODING GENE AND APPLICATION THEREOF

The present disclosure provides an O-methyltransferase protein with highly specific catalytic function for multiple BIAS parent nuclei, a coding gene and an application thereof. Compared with wild-type O methyltransferase, the enzyme protein (SEQ ID NO: 2) has improved enzymatic activity and a wider substrate range, and can catalyze three benzylisoquinoline alkaloid skeletons, including monobenzylisoquinolines (norcoclaurine, coclaurine, N-methylcoclaurin), aporphines (asimilobine, N-Methlyasimilobine) and protoberberines (scoulerine, tetrahydrocolumbamine) to have O-methylation reactions. Meanwhile, each skeleton has a high degree of regioselectivity, can catalyze the methylation of monobenzylisoquinolines at 6-OH and 7-OH, and is only active on the 6-OH of the aporphine skeleton, mainly catalyzing the methylation of proberberines at 2-OH and having strong catalytic activity; therefore, they can be used biocatalysts in the semi-synthesis of related compounds.