Many biosynthesis clusters for secondary metabolites feature a glycosyltransferase gene next to a P450 homolog, often with the P450 lacking a critical heme-binding Cys. These P540-derived sequences seem to be allosteric activators of glycosyltransferases such as the member of this family. This model describes a set of related glycosyltransferases, many of which can be recognized as activator-dependent from genomic context.
Jiyao W et al.(2023). "The conserved domain database in 2023.",