English   español  
Please use this identifier to cite or link to this item: http://hdl.handle.net/10261/178047
logo share SHARE   Add this article to your Mendeley library MendeleyBASE
Visualizar otros formatos: MARC | Dublin Core | RDF | ORE | MODS | METS | DIDL
Exportar a otros formatos:

Molecular and biochemical characterization of the sunflower (Helianthus annuus L.) cytosolic and plastidial enolases in relation to seed development

AuthorsTroncoso-Ponce, M. Adrián ; Rivoal, J.; Dorion, S.; Sánchez, Rosario ; Venegas-Calerón, Mónica ; Moreno-Pérez, Antonio J.; Baud, S.; Garcés Mancheño, Rafael ; Martínez-Force, Enrique
Glycolytic metabolism
Issue DateJul-2018
CitationPlant science 272: 117-130 (2018)
AbstractIn the present study, we describe the molecular and biochemical characterization of sunflower (Helianthus annuus L.) enolase (ENO, EC proteins, which catalyze the formation of phosphoenolpyruvate, the penultimate intermediate in the glycolytic pathway. We cloned and characterized three cDNAs encoding different ENO isoforms from developing sunflower seeds. Studies using fluorescently tagged ENOs confirmed the predicted subcellular localization of ENO isoforms: HaENO1 in the plastid while HaENO2 and HaENO3 were found in the cytosol. The cDNAs were used to express the corresponding 6(His)-tagged proteins in Escherichia coli. The proteins were purified to electrophoretic homogeneity, using immobilized metal ion affinity chromatography, and biochemically characterized. Recombinant HaENO1 and HaENO2, but not HaENO3 were shown to have enolase activity, in agreement with data obtained with the Arabidopsis homolog proteins. Site directed mutagenesis of several critical amino acids was used to attempt to recover enolase activity in recombinant HaENO3, resulting in very small increases that were not additive. A kinetic characterization of the two active isoforms showed that pH had similar effect on their velocity, that they had similar affinity for 2-phosphoglycerate, but that the kcat/Km of the plastidial enzyme was higher than that of the cytosolic isoform. Even though HaENO2 was always the most highly expressed transcript, the levels of expression of the three ENO genes were remarkably distinct in all the vegetative and reproductive tissues studied. This indicates that in seeds the conversion of 2-phosphoglycerate to phosphoenolpyruvate takes place through the cytosolic and the plastidial pathways therefore both routes could contribute to the supply of carbon for lipid synthesis. The identity of the main source of carbon during the period of stored products synthesis is discussed.
Description57 Páginas.-- 2 Tablas.-- 10 Figuras.-- 3 Tablas suplementarias.-- 5 Figuras suplementarias
Publisher version (URL)http://dx.doi.org/10.1016/j.plantsci.2018.04.007
Appears in Collections:(IG) Artículos
Files in This Item:
File Description SizeFormat 
PostP_2018_PlantSci_V272_P117.pdf Embargoed until July 1, 2020Artículo principal2,83 MBAdobe PDFThumbnail
View/Open    Request a copy
Show full item record
Review this work

WARNING: Items in Digital.CSIC are protected by copyright, with all rights reserved, unless otherwise indicated.