| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
|
First published online September 17, 2008; 10.1104/pp.108.125757 Plant Physiology 148:1721-1733 (2008) © 2008 American Society of Plant Biologists
Subclade of Flavin-Monooxygenases Involved in Aliphatic Glucosinolate Biosynthesis1,[W]Plant Biochemistry Laboratory, Department of Plant Biology and Villum Kann Rasmussen Research Centre for Pro-Active Plants, Faculty of Life Sciences, University of Copenhagen, DK–1871 Frederiksberg C, Denmark (J.L., B.G.H., B.A.H.); and Department of Plant Sciences, University of California, Davis, California 95616–8780 (J.A.O., D.J.K.)
Glucosinolates (GSLs) are amino acid-derived secondary metabolites with diverse biological activities dependent on chemical modifications of the side chain. We previously identified the flavin-monooxygenase FMOGS-OX1 as an enzyme in the biosynthesis of aliphatic GSLs in Arabidopsis (Arabidopsis thaliana) that catalyzes the S-oxygenation of methylthioalkyl to methylsulfinylalkyl GSLs. Here, we report the fine mapping of a quantitative trait locus for the S-oxygenating activity in Arabidopsis. In this region, there are three FMOs that, together with FMOGS-OX1 and a fifth FMO, form what appears to be a crucifer-specific subclade. We report the identification of these four uncharacterized FMOs, designated FMOGS-OX2 to FMOGS-OX5. Biochemical characterization of the recombinant protein combined with the analysis of GSL content in knockout mutants and overexpression lines show that FMOGS-OX2, FMOGS-OX3, and FMOGS-OX4 have broad substrate specificity and catalyze the conversion from methylthioalkyl GSL to the corresponding methylsulfinylalkyl GSL independent of chain length. In contrast, FMOGS-OX5 shows substrate specificity toward the long-chain 8-methylthiooctyl GSL. Identification of the FMOGS-OX subclade will generate better understanding of the evolution of biosynthetic activities and specificities in secondary metabolism and provides an important tool for breeding plants with improved cancer prevention characteristics as provided by the methylsulfinylalkyl GSL.
1 This work was supported by the Villum Kann Rasmussen (VKR) Foundation (grant to VKR Research Centre for Pro-Active Plants); the National Science Foundation (grant nos. DBI–0642481 and MCB–0323759 to D.J.K.); Research School for Biotechnology graduate school (Ph.D. stipend to B.G.H.); and a Marie Curie IIF fellowship (contract no. MIF1–CT–2006–022344 to J.L.). 2 These authors contributed equally to the article. 3 Present address: Center for Microbial Biotechnology, Department of Systems Biology, Technical University of Denmark, DK–2800 Kgs. Lyngby, Denmark. The author responsible for distribution of materials integral to the findings presented in this article in accordance with the policy described in the Instructions for Authors (www.plantphysiol.org) is: Barbara Ann Halkier (bah{at}life.ku.dk). [W] The online version of this article contains Web-only data. www.plantphysiol.org/cgi/doi/10.1104/pp.108.125757 * Corresponding author; e-mail bah{at}life.ku.dk. Received July 7, 2008; accepted September 14, 2008; published September 17, 2008. This article has been cited by other articles:
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| ASPB Publications | PLANT PHYSIOLOGY® | THE PLANT CELL | |
|---|---|---|---|
