Fig. 1 in Site directed mutagenesis of Catharanthus roseus (+)-vincadifformine 19-hydroxylase (CYP71BY3) results in two distinct enzymatic functions

Fig. 1. The formation of (þ)- and (¡)-aspidosperma MIAs in Catharanthus roseus. In multiple C. roseus tissues, the ()-aspidosperma pathways begin with the biosynthesis of ()-tabersonine (1) from O-acetylstemmadenine (18) through acetylstemmadenine oxygenase (ASO), geissoschizine synthase (GS), and hydrolase 1 (HL1), whereas the (+)-aspidosperma pathway requires hydrolase 3 or 4 (HL3/4) to produce (+)-vincadifformine (15). Leaf-specific enzymes (black) convert ()-tabersonine (1) to vindoline (6), which accumulates in the leaves, while root-specific enzymes (purple) are responsible for the formation of two major root alkaloids, lochnericine (7) and h¨orhammericine (8). A third major root alkaloid, (+)-echitovenine (17) is derived from (+)-vincadifformine (15) via (+)-minovincinine (16) by separate root-specific (blue) enzymes. The remaining ()-aspidosperma alkaloids shown are derived chemically (grey box) from ()-tabersonine (1) to generate ()-vincadifformine (12) or enzymatic conversion by T19H to form 19-hydroxytabersonine (10) or its 19-O acetyltabersonine (11) by the action of TAT. These MIAs [()-vincadifformine (12), 19-hydroxytabersonine (10) and 19-O acetyltabersonine (11)] do not naturally accumulate in C. roseus. T16H: tabersonine 16-hydroxylase [CYP71D12 (T16H1) or CYP71D351 (T16H2); 16OMT: tabersonine 16-O-methyltransferase; T3O: tabersonine 3-oxygenase (CYP71D1V2); T3R: tabersonine 3-reductase; NMT: N-methyltransferase; D4H: desacetoxyvindoline 4-hydroxylase; DAT: deacetylvindoline O-acetyltransferase; TEX: tabersonine epoxidase [CYP71D521 (TEX1) or CYP71D347 (TEX2)]; T19H: tabersonine 19-hydroxylase (CYP71BJ1); TAT: tabersonine 19-acetyltranferase; V19H: (+)-vincadifformine 19-hydroxylase (CYP71BY3); MAT: minovincinine 19-O-acetyltransferase. (For interpretation of the references to colour in this figure legend, the reader is referred to the Web version of this article.)