Light-induced cytochrome P450-dependent enzyme in indole alkaloid biosynthesis: tabersonine 16-hydroxylase

Vinblastine and vincristine are two medically important bisindole alkaloids from Catharanthus roseus (Madagascar periwinkle). Attempts at production i n cell cultures failed because a part of the complex pathway was not active , i,e, from tabersonine to vindoline, It starts with tabersonine 16-hydroxy lase (T16H), a cytochrome P450-dependent enzyme, We now show that T16H is i nduced in the suspension culture by light and we report the cloning of the cDNA, The enzyme was expressed in Escherichia coli as translational fusion with the P450 reductase from C, roseus, and the reaction product was identi fied by mass spectrometry, The protein (CYP71D12) shares 47-52% identity wi th other members of the CYP71D subfamily with unknown function, The inducti on by light was strongly enhanced by a nutritional downshift (transfer into 8% aqueous sucrose), We discuss the possibility that the entire pathway to bisindoles can be expressed in suspension cultures. (C) 1999 Federation of European Biochemical Societies.