EC Number   |
General Information |
Reference |
|---|
   2.7.9.4 | evolution |
phylogenetic analysis of the cassava GWD sequences with other plant GWDs reveal that the cassava GWD belongs to the same group as that of Ricinus communis, Solanum tuberosum, Solanum lycopersicum, and Nicotiana sanderae |
738441 |
| 2.7.9.4 | evolution |
significant diversity in the evolution of alpha-glucan, water dikinase enzymes across plant species may be evolutionarily advantageous according to the varying needs for phosphorylated stored starch between plants and environments. Computational approaches to compare the enzyme sequences of 48 plant species provide an insight into the evolutionary variation in catalytic activity of alpha-glucan, water dikinase among plants. Deleterious mutations are identified for some plants at various positions of the five aromatic amino acids, which are highly conserved in tandems of CBM45 and vital for binding of the enzymes to starch. These mutations may be responsible for altered carbohydrate binding activity of alpha-glucan, water dikinase in plants, thereby affecting phosphorylation of transit and stored starch |
762189 |
| 2.7.9.4 | evolution |
the largest differences in the amino acid sequence of GWD, EC 2.7.9.4, and PWD, EC 2.7.9.5, span the non-catalytic N-terminal region. In case of PWD, the N-terminus contains a single starch-binding domain (SBD) that belongs to the well-characterized carbohydrate-binding module (CBM) family CBM20. In contrast to PWD, the identity of the N-terminal starch-binding domain of GWD is less pronounced but might be assigned to the recently identified CBM45 family |
738013 |
| 2.7.9.4 | malfunction |
analysis of changes in GWD protein abundance in relation to starch levels in wild-type plants, in transgenic plants in which GWD transcripts are strongly reduced by induction of RNA interference, and in transgenic plants overexpressing GWD, overview. Overexpression of GWD does not accelerate starch degradation in leaves, and starch degradation is not inhibited until GWD levels are reduced by 70%. GWD protein levels do not vary over the diel cycle and the protein has a half-life of 2 days. Plants expressing redox-insensitive GWD have normal starch turnover |
739353 |
| 2.7.9.4 | malfunction |
AtGWD2 knockout mutants do not accumulate high amounts of starch nor have a visible growth phenotype compared to wild-type plants |
738013 |
| 2.7.9.4 | malfunction |
downregulation of the enzyme causes phenotypic alteration in grain and growth. Coleoptile length is increased in these transgenic lines independently of grain size increases. The GWD-depleted wheat lines exhibit unexpected increases in grain size, early vigour and plant biomass. No changes in starch degradation rates during germination are identified, or any major alteration in soluble sugar levels that may explain the coleoptile growth modification. There is no evidence that the increased growth of coleoptiles in these lines is connected to starch conformation or degradation or soluble sugar content. Phenotype, overview |
739271 |
| 2.7.9.4 | malfunction |
GWD-deficient Arabidopsis thaliana mutants have a starch excess phenotype (sex1). The internal structure of granules isolated from GWD mutant plants, having reduced or no GWD activity, is unaffected, as thermal stability, allomorph, chain length distribution and density of starch granules are similar to wild-type, but short glucan chain residues located at the granule surface dominate in starches of transgenic plants and impede GWD activity. A similarly reduced rate of phosphorylation by GWD is also observed in potato tuber starch fractions that differ in the proportion of accessible glucan chain residues at the granule surface. A model is proposed to explain the characteristic morphology of starch granules observed in GWD transgenic plants. The model postulates that the occupancy rate of single glucan chains at the granule surface limits accessibility to starch-related enzymes |
739181 |
| 2.7.9.4 | malfunction |
gwd2 mutants are shrunken, with the epidermal cells of the seed coat irregularly shaped. gwd2 seeds contain a lower lipid to protein ratio and are impaired in germination |
762113 |
| 2.7.9.4 | malfunction |
in glasshouse pot trials, enzyme down-regulation leads to a 29% increase in grain yield while in glasshouse tub trials simulating field row spacing and canopy development, enzyme down-regulation results in a grain yield increase of 26%. Decreased activity of the enzyme is correlated with an increase in alpha-amylase activity |
723376 |
| 2.7.9.4 | malfunction |
melting enthalpy and crystallinity of purified starches are higher if GWD-mediated starch phosphorylation is suppressed. R1 reduction results in a starch excess phenotype in leaves, e.g., the accumulation of high amounts of starch at the end of a normal dark phase because of the decreased rates of leaf starch degradation. In addition, the lowered expression of R1 in these plants is accompanied by a reduction in cold-induced sweeting in tubers. Transgenic potato plants with reduced StGWD expression, show impeded starch degradation and an overall reduction in starch phosphate content. In transgenic potato lines with reduced expression of StGWD, small alteration in storage starch metabolism is reported |
738013 |
