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- Title
Structural Insights into Maize Viviparous14, a Key Enzyme in the Biosynthesis of the Phytohormone Abscisic Acid.
- Authors
Messing, Simon A.J.; Gabelli, Sandra B.; Echeverria, Ignacia; Vogel, Jonathan T.; Guan, Jiahn Chou; Tan, Bao Cai; Klee, Harry J.; McCarty, Donald R.; Amzel, L. Mario
- Abstract
The key regulatory step in the biosynthesis of abscisic acid (ABA), a hormone central to the regulation of several important processes in plants, is the oxidative cleavage of the 11,12 double bond of a 9- cis -epoxycarotenoid. The enzyme viviparous14 (VP14) performs this cleavage in maize (Zea mays), making it a target for the rational design of novel chemical agents and genetic modifications that improve plant behavior through the modulation of ABA levels. The structure of VP14, determined to 3.2-Å resolution, provides both insight into the determinants of regio- and stereospecificity of this enzyme and suggests a possible mechanism for oxidative cleavage. Furthermore, mutagenesis of the distantly related CCD1 of maize shows how the VP14 structure represents a template for all plant carotenoid cleavage dioxygenases (CCDs). In addition, the structure suggests how VP14 associates with the membrane as a way of gaining access to its membrane soluble substrate.
- Subjects
BIOSYNTHESIS; CORN; STEREOSPECIFICITY; ENZYMES; DOUBLE bonds; ABSCISIC acid
- Publication
Plant Cell, 2010, Vol 22, Issue 9, p2970
- ISSN
1040-4651
- Publication type
Article
- DOI
10.1105/tpc.110.074815