Abiotic Stress/Whole Plant Bio

Abstract

CS-19-2 - EARLY STARVATION1 specifically affects the phosphorylation action of starch-related dikinases.

Monday, July 16
3:38 PM - 3:58 PM

Transitory starch is synthesized in the light and degraded in the following dark phase. During the starch degradation starch phosphorylation by starch related dikinases GWD and PWD is a key step. However, little 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 found by mass spectrometry bound to starch. In various in vitro assays, the influence of the recombinant protein ESV1 on the action of different starch-related enzymes, including GWD, PWD, SS1, SS3, SEX4, and isoamylase, on the surfaces of native starchgranules were analyzed. In addition, we included starches from various sources as well as truncated forms of GWD. ESV1 preferentially binds to highly ordered, insoluble a-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 theaction of PWD increases in the presence of ESV1. The actions of other starch-related enzymes were unaffected by ESV1. The unique alterations observed in starch phosphorylation by the two dikinases is discussed in regard to altered glucan structures at the starch granule surface.


 

Joerg Fettke

Prof
University of Potsdam

Curriculum vitae apl. Prof. Dr. habil Joerg Fettke

Citizenship: German
Present address: University of Potsdam, Institute of Biology and
Biochemistry, Karl-Liebknechtstr. 24/25, Building 20, 14476
Potsdam-Golm
Present and previous positions: 2007- 2011 Principal investigator group Plant Physiology at University of Potsdam
2008-2011 Leader of Mass Spectrometry unit at the University of Potsdam
2008- 2010 Project leader SFB429 ´Signals, sensing and plant primary metabolism´
2011-2013 Deputy chair (Lehrstuhlvertretung) Plant Physiology at University of Potsdam
2012 -2016 Visiting Professor Plant Biochemistry University of Life Science, Warsaw, Poland
2014 - Leader of the Biopolymer Analytics group at the University of Potsdam

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