- Molecular basis for the production of cyclic peptides by plant asparaginyl endopeptidases
- Gene-guided discovery and engineering of branched cyclic peptides in plants
- Enzyme Fusion Removes Competition for Geranylgeranyl Diphosphate in Carotenogenesis
- Neopinone isomerase is involved in codeine and morphine biosynthesis in opium poppy
- Computational Approaches to Design and Test Plant Synthetic Metabolic Pathways
- Changing Form and Function through Carotenoids and Synthetic Biology
- Unleashing the Synthetic Power of Plant Oxygenases: From Mechanism to Application
- Parts-Prospecting for a High-Efficiency Thiamin Thiazole Biosynthesis Pathway
- Engineering of plastids to optimize the production of high-value metabolites and proteins
- Computational approaches to design and test plant synthetic metabolic pathways
- Improving the efficiency of photosynthetic carbon reactions
- Engineering of metabolic pathways using synthetic enzyme complexes
- Synthetic metabolic pathways for photobiological conversion of CO2 into hydrocarbon fuel
- Molecular Plant: Special Issue on Plant Metabolism and Synthetic Biology (2014)
Parts-Prospecting for a High-Efficiency Thiamin Thiazole Biosynthesis Pathway
- © 2019 American Society of Plant Biologists. All rights reserved.
Plants synthesize the thiazole precursor of thiamin (cThz-P) via THIAMIN4 (THI4), a suicide enzyme that mediates one reaction cycle and must then be degraded and resynthesized. It has been estimated that this THI4 turnover consumes 2% to 12% of the maintenance energy budget and that installing an energy-efficient alternative pathway could substantially increase crop yield potential. Available data point to two natural alternatives to the suicidal THI4 pathway: (i) nonsuicidal prokaryotic THI4s that lack the active-site Cys residue on which suicide activity depends, and (ii) an uncharacterized thiazole synthesis pathway in flowers of the tropical arum lily Caladium bicolor that enables production and emission of large amounts of the cThz-P analog 4-methyl-5-vinylthiazole (MVT). We used functional complementation of an Escherichia coli ΔthiG strain to identify a nonsuicidal bacterial THI4 (from Thermovibrio ammonificans) that can function in conditions like those in plant cells. We explored whether C. bicolor synthesizes MVT de novo via a novel route, via a suicidal or a nonsuicidal THI4, or by catabolizing thiamin. Analysis of developmental changes in MVT emission, extractable MVT, thiamin level, and THI4 expression indicated that C. bicolor flowers make MVT de novo via a massively expressed THI4 and that thiamin is not involved. Functional complementation tests indicated that C. bicolor THI4, which has the active-site Cys needed to operate suicidally, may be capable of suicidal and – in hypoxic conditions – nonsuicidal operation. T. ammonificans and C. bicolor THI4s are thus candidate parts for rational redesign or directed evolution of efficient, nonsuicidal THI4s for use in crop improvement.
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