TY  - JOUR
A1  - Dauvillee, David
A1  - Chochois, Vincent
A1  - Steup, Martin
A1  - Haebel, Sophie
A1  - Eckermann, Nora
A1  - Ritte, Gerhard
A1  - Ral, Jean-Philippe
A1  - Colleoni, Christophe
A1  - Hicks, Glenn
A1  - Wattebled, Fabrice
A1  - Deschamps, Philippe
A1  - Lienard, Luc
A1  - Cournac, Laurent
A1  - Putaux, Jean-Luc
A1  - Dupeyre, Danielle
A1  - Ball, Steven G.
T1  - Plastidial phosphorylase is required for normal starch synthesis in Chlamydomonas reinhardtii
JF  - The plant journal
N2  - Among the three distinct starch phosphorylase activities detected in Chlamydomonas reinhardtii, two distinct plastidial enzymes (PhoA and PhoB) are documented while a single extraplastidial form (PhoC) displays a higher affinity for glycogen as in vascular plants. The two plastidial phosphorylases are shown to function as homodimers containing two 91-kDa (PhoA) subunits and two 110-kDa (PhoB) subunits. Both lack the typical 80-amino-acid insertion found in the higher plant plastidial forms. PhoB is exquisitely sensitive to inhibition by ADP-glucose and has a low affinity for malto-oligosaccharides. PhoA is more similar to the higher plant plastidial phosphorylases: it is moderately sensitive to ADP-glucose inhibition and has a high affinity for unbranched malto-oligosaccharides. Molecular analysis establishes that STA4 encodes PhoB. Chlamydomonas reinhardtii strains carrying mutations at the STA4 locus display a significant decrease in amounts of starch during storage that correlates with the accumulation of abnormally shaped granules containing a modified amylopectin structure and a high amylose content. The wild-type phenotype could be rescued by reintroduction of the cloned wild-type genomic DNA, thereby demonstrating the involvement of phosphorylase in storage starch synthesis.
KW  - Chlamydomonas
KW  - starch
KW  - amylopectin
KW  - (glycogen) starch phosphorylase
Y1  - 2006
U6  - https://doi.org/10.1111/j.1365-313X.2006.02870.x
SN  - 0960-7412
VL  - 48
IS  - 2
SP  - 274
EP  - 285
PB  - Blackwell
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Deschamps, Philippe
A1  - Haferkamp, Ilka
A1  - Dauvillee, David
A1  - Haebel, Sophie
A1  - Steup, Martin
A1  - Buleon, Alain
A1  - Putaux, Jean-Luc
A1  - Colleoni, Christophe
A1  - d'Hulst, Christophe
A1  - Plancke, Charlotte
A1  - Gould, Sven
A1  - Maier, Uwe
A1  - Neuhaus, Heinz Eckhard
A1  - Ball, Steven G.
T1  - Nature of the periplastidial pathway of starch synthesis in the cryptophyte Guillardia theta
N2  - The nature of the periplastidial pathway of starch biosynthesis was investigated with the model cryptophyte Guillardia theta. The storage polysaccharide granules were shown to be composed of both amylose and amylopectin fractions with a chain length distribution and crystalline organization very similar to those of starch from green algae and land plants. Most starch granules displayed a shape consistent with biosynthesis occurring around the pyrenoid through the rhodoplast membranes. A protein with significant similarity to the amylose-synthesizing granule-bound starch syntbase 1 from green plants was found as the major polypeptide bound to the polysaccharide matrix. N-terminal sequencing of the mature protein proved that the precursor protein carries a nonfunctional transit peptide in its bipartite topogenic signal sequence which is cleaved without yielding transport of the enzyme across the two inner plastid membranes. The enzyme was shown to display similar affinities for ADP and UDP-glucose, while the V-max measured with UDP-glucose was twofold higher. The granule-bound starch synthase from Guillardia theta was demonstrated to be responsible for the synthesis of long glucan chains and therefore to be the functional equivalent of the amylose- synthesizing enzyme of green plants. Preliminary characterization of the starch pathway suggests that Guillardia theta utilizes a UDP-glucose-based pathway to synthesize starch
Y1  - 2006
UR  - http://ec.asm.org/
U6  - https://doi.org/10.1128/Ec.00380-05
SN  - 1535-9778
ER  -