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Abstract Detail


Secondary Metabolism

Hampel, Daniela [1], Mau, Christopher J.D. [2], Croteau, Rodney B. [2].

Taxol Biosynthesis: Acyl and Aroyl Transferases.

Mapping the complete biosynthetic pathway of the diterpenoid Taxol is essential for the production of this anticancer drug in genetically engineered organisms. More than half of the approximately 20 enzymes involved in taxol biosynthesis have been identified. As suggested by metabolic studies of Taxus suspension cell cultures, acyl and aroyl transferases act as branch points for on- and off-pathway intermediate compounds. Thus, these enzymes play an important role in the pathway flux towards taxol. The screening of a constructed cDNA library using induced Taxus cupsidata suspension cells has revealed 15 related cDNAs encoding this transferase type with > 65% similarity within the group. Heterologous expression in E. coli and assay of the derived soluble, recombinant enzyme preparations has already resulted in the identification of taxadien-5α-ol-O-acetyl transferase, taxoid-2α-O-benzoyl transferase, taxoid-10β-O-acetyl transferase and the two transferases involved in C13-side chain assembly. Since not all of the taxoid precursors are available, surrogate substrates, purified from Taxus cell extracts and isotopically labeled, could be used to identify the transferases with other proposed activities. Moreover, the refinement of cDNA expression and protein purification (INMAC) protocols allows access to partial purified enzymes in higher concentrations. Thus, these advancements offer a new approach for functional analysis and characterization of candidate cDNAs from the extant family of acyl and aroyl transferases genes for providing a better insight into this complex pathway.


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1 - Institute of Biological Chemistry, Washington State University, Clark 299, Pullman, WA, 99164-6340, USA
2 - Institute of Biological Chemistry, Washington State University

Keywords:
taxol
biosynthesis
acyl/aroyl transferases.

Presentation Type: Plant Biology Abstract
Session: P
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM
Number: P20033
Abstract ID:1089


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