@article{MalinovaMahtoBrandtetal.2018,
  author    = {Malinova, Irina and Mahto, Harendra and Brandt, Felix and AL-Rawi, Shadha and Qasim, Hadeel and Brust, Henrike and Hejazi, Mahdi and Fettke, J{\"o}rg},
  title     = {EARLY STARVATION1 specifically affects the phosphorylation action of starch-related dikinases},
  series = {The plant journal},
  volume    = {95},
  journal   = {The plant journal},
  number    = {1},
  publisher = {Wiley},
  address   = {Hoboken},
  issn      = {0960-7412},
  doi       = {10.1111/tpj.13937},
  pages     = {126 -- 137},
  year      = {2018},
  abstract  = {Starch phosphorylation by starch-related dikinases glucan, water dikinase (GWD) and phosphoglucan, water dikinase (PWD) is a key step in starch degradation. Little information is known about the precise structure of the glucan substrate utilized by the dikinases and about the mechanisms by which these structures may be influenced. A 50-kDa starch-binding protein named EARLY STARVATION1 (ESV1) was analyzed regarding its impact on starch phosphorylation. In various invitro assays, the influences of the recombinant protein ESV1 on the actions of GWD and PWD on the surfaces of native starch granules were analyzed. In addition, we included starches from various sources as well as truncated forms of GWD. ESV1 preferentially binds to highly ordered, -glucans, such as starch and crystalline maltodextrins. Furthermore, ESV1 specifically influences the action of GWD and PWD at the starch granule surface. Starch phosphorylation by GWD is decreased in the presence of ESV1, whereas the action of PWD increases in the presence of ESV1. The unique alterations observed in starch phosphorylation by the two dikinases are discussed in regard to altered glucan structures at the starch granule surface.},
  language  = {en}
}
@article{MahlowHejaziKuhnertetal.2014,
  author    = {Mahlow, Sebastian and Hejazi, Mahdi and Kuhnert, Franziska and Garz, Andreas and Brust, Henrike and Baumann, Otto and Fettke, J{\"o}rg},
  title     = {Phosphorylation of transitory starch by -glucan, water dikinase during starch turnover affects the surface properties and morphology of starch granules},
  series = {New phytologist : international journal of plant science},
  volume    = {203},
  journal   = {New phytologist : international journal of plant science},
  number    = {2},
  publisher = {Wiley-Blackwell},
  address   = {Hoboken},
  issn      = {0028-646X},
  doi       = {10.1111/nph.12801},
  pages     = {495 -- 507},
  year      = {2014},
  abstract  = {Glucan, water dikinase (GWD) is a key enzyme of starch metabolism but the physico-chemical properties of starches isolated from GWD-deficient plants and their implications for starch metabolism have so far not been described. Transgenic Arabidopsis thaliana plants with reduced or no GWD activity were used to investigate the properties of starch granules. In addition, using various in vitro assays, the action of recombinant GWD, -amylase, isoamylase and starch synthase 1 on the surface of native starch granules was analysed. The internal structure of granules isolated from GWD mutant plants is unaffected, as thermal stability, allomorph, chain length distribution and density of starch granules were similar to wild-type. However, 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 was 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.},
  language  = {en}
}