Pathway of cytosolic starch synthesis in the model glaucophyte Cyanophora paradoxa |
| |
Authors: | Plancke Charlotte Colleoni Christophe Deschamps Philippe Dauvillée David Nakamura Yasunori Haebel Sophie Ritte Gehrardt Steup Martin Buléon Alain Putaux Jean-Luc Dupeyre Danielle d'Hulst Christophe Ral Jean-Philippe Löffelhardt Wolfgang Ball Steven G |
| |
Affiliation: | Charlotte Plancke, Christophe Colleoni, Philippe Deschamps, David Dauvillée, Yasunori Nakamura, Sophie Haebel, Gehrardt Ritte, Martin Steup, Alain Buléon, Jean-Luc Putaux, Danielle Dupeyre, Christophe d'Hulst, Jean-Philippe Ral, Wolfgang Löffelhardt, and Steven G. Ball |
| |
Abstract: | The nature of the cytoplasmic pathway of starch biosynthesis was investigated in the model glaucophyte Cyanophora paradoxa. The storage polysaccharide granules are shown to be composed of both amylose and amylopectin fractions, with a chain length distribution and crystalline organization similar to those of green algae and land plant starch. A preliminary characterization of the starch pathway demonstrates that Cyanophora paradoxa contains several UDP-glucose-utilizing soluble starch synthase activities related to those of the Rhodophyceae. In addition, Cyanophora paradoxa synthesizes amylose with a granule-bound starch synthase displaying a preference for UDP-glucose. A debranching enzyme of isoamylase specificity and multiple starch phosphorylases also are evidenced in the model glaucophyte. The picture emerging from our biochemical and molecular characterizations consists of the presence of a UDP-glucose-based pathway similar to that recently proposed for the red algae, the cryptophytes, and the alveolates. The correlative presence of isoamylase and starch among photosynthetic eukaryotes is discussed. |
| |
Keywords: | |
本文献已被 PubMed 等数据库收录! |
|