title: Contribution of hydroxymethylbutenyl diphosphate synthase to carotenoid biosynthesis in bacteria and plants.
abstract: The methylerythritol 4-phosphate (MEP) pathway synthesizes the precursors of carotenoids and other isoprenoids in bacteria and plant plastids. Despite recent progress in the identification of rate-determining steps, the relative contribution of most pathway enzymes to flux control remains to be established. In this work we investigated whether upregulated levels of hydroxymethylbutenyl diphosphate synthase (HDS) could increase the metabolic flux through this pathway, as judged by endpoint (carotenoid) measurements. Unlike other MEP pathway enzymes, however, increasing the levels of an active HDS protein in carotenoid-producing Escherichia coli cells and transgenic Arabidopsis thaliana plants did not result in an enhanced accumulation of MEP-derived isoprenoids. Our data suggest that enhanced flux through the MEP pathway for peak demand periods in bacteria and plastids does not require increased HDS activity.
authors.affiliation: Departament de Genètica Molecular de Plantes, Consorci CSIC-IRTA, Jordi Girona 18, 08034 Barcelona, Spain.
authors.forename: Ursula
authors.initials: U
authors.lastname: Flores-Pérez
authors.forename: Jordi
authors.initials: J
authors.lastname: Pérez-Gil
authors.forename: Antía
authors.initials: A
authors.lastname: Rodríguez-Villalón
authors.forename: María José
authors.initials: MJ
authors.lastname: Gil
authors.forename: Pablo
authors.initials: P
authors.lastname: Vera
authors.forename: Manuel
authors.initials: M
authors.lastname: Rodríguez-Concepción
mesh_terms: D017360:Arabidopsis / Q000201:enzymology*; D029681:Arabidopsis Proteins / Q000378:metabolism*; D002338:Carotenoids / Q000096:biosynthesis*; D004798:Enzymes / Q000378:metabolism*; D004896:Erythritol / Q000031:analogs & derivatives / Q000378:metabolism; D004926:Escherichia coli / Q000201:enzymology*; D029968:Escherichia coli Proteins / Q000378:metabolism*; D018087:Plastids / Q000201:enzymology; D013403:Sugar Phosphates / Q000378:metabolism; D015854:Up-Regulation
chemical_list: C114232:2-C-methylerythritol 4-phosphate; D029681:Arabidopsis Proteins; D004798:Enzymes; D029968:Escherichia coli Proteins; D013403:Sugar Phosphates; C421242:hydroxymethylbutenyl 4-diphosphate synthase; D002338:Carotenoids; D004896:Erythritol