TY  - JOUR
A1  - Ritte, Gerhard
A1  - Heydenreich, Matthias
A1  - Mahlow, Sebastian
A1  - Haebel, Sophie
A1  - Koetting, Oliver
A1  - Steup, Martin
T1  - Phosphorylation of C6- and C3-positions of glucosyl residues in starch is catalysed by distinct dikinases
JF  - FEBS letters : the journal for rapid publication of short reports in molecular biosciences
N2  - Glucan, water dikinase (GWD) and phosphoglucan, water dikinase (PWD) are required for normal starch metabolism. We analysed starch phosphorylation in Arabidopsis wildtype plants and mutants lacking either GWD or PWD using P-31 NMR. Phosphorylation at both C6- and C3-positions of glucose moieties in starch was drastically decreased in GWD-deficient mutants. In starch from PWD-deficient plants C3-bound phosphate was reduced to levels close to the detection limit. The latter result contrasts with previous reports according to which GWD phosphorylates both C6- and C3-positions. In these studies, phosphorylation had been analysed by HPLC of acid-hydrolysed glucans. We now show that maltose-6-phosphate, a product of incomplete starch hydrolysis, co-eluted with glucose-3-phosphate under the chromatographic conditions applied. Re-examination of the specificity of the dikinases using an improved method demonstrates that C6- and C3-phosphorylation is selectively catalysed by GWD and PWD, respectively.
KW  - starch phosphorylation
KW  - GWD
KW  - PWD
KW  - P-31 NMR
Y1  - 2006
U6  - https://doi.org/10.1016/j.febslet.2006.07.085
SN  - 0014-5793
VL  - 580
IS  - 20
SP  - 4872
EP  - 4876
PB  - Elsevier
CY  - Amsterdam
ER  -