title: Taxol biosynthesis: Molecular cloning and characterization of a cytochrome P450 taxoid 7 beta-hydroxylase.
abstract: Biosynthesis of the anticancer drug Taxol in yew species involves eight cytochrome P450-mediated oxygenations and four coenzyme A-dependent acylations of the diterpenoid core. A family of cytochrome P450 genes, obtained from a yew cell cDNA library, were functionally expressed and screened with taxusin (taxa-4(20),11(12)-dien-5 alpha,9 alpha,10 beta,13 alpha-tetraol tetraacetate) as a surrogate substrate. One clone converted this substrate to an oxygenated derivative that was identified as 7 beta-hydroxytaxusin. The structure and properties of this 7 beta-hydroxylase are similar to those of other taxoid hydroxylases. Kinetic and binding assays indicated selectivity of the 7 beta-hydroxylase for polyoxygenated and acylated taxoid substrates, an observation consistent with the operation of this enzyme in the central portion of the Taxol biosynthetic pathway. Although the 7 beta-hydroxyl of Taxol is not essential for antimitotic activity, this functional group provides a convenient means for preparing taxoid derivatives.
authors.affiliation: Institute of Biological Chemistry, Washington State University, Pullman, WA 99164, USA.
authors.forename: MyDoanh
authors.initials: M
authors.lastname: Chau
authors.forename: Stefan
authors.initials: S
authors.lastname: Jennewein
authors.forename: Kevin
authors.initials: K
authors.lastname: Walker
authors.forename: Rodney
authors.initials: R
authors.lastname: Croteau
mesh_terms: D000972:Antineoplastic Agents, Phytogenic / Q000096:biosynthesis* / Q000737:chemistry; D001483:Base Sequence; D003001:Cloning, Molecular; D003577:Cytochrome P-450 Enzyme System / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D006899:Mixed Function Oxygenases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D008969:Molecular Sequence Data; D017239:Paclitaxel / Q000096:biosynthesis* / Q000737:chemistry; D016415:Sequence Alignment
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D003577:Cytochrome P-450 Enzyme System; D006899:Mixed Function Oxygenases; D017239:Paclitaxel