A novel isoform of glucan, water dikinase phosphorylates pre‐phosphorylated α‐glucans and is involved in starch degradation in Arabidopsis
摘要：
An Arabidopsis thaliana gene encoding a homologue of the potato α -glucan, water dikinase GWD, previously known as R1, was identified by screening the Arabidopsis genome and named AtGWD3 . The AtGWD3 cDNA was isolated, heterologously expressed and the protein was purified to apparent homogeneity to determine the enzymatic function. In contrast to the potato GWD protein, the AtGWD3 primarily catalysed phosphorylation at the C-3 position of the glucose unit of preferably pre-phosphorylated amylopectin substrate with long side chains. An Arabidopsis mutant, termed Atgwd3 , with downregulated expression of the AtGWD3 gene was analysed. In Atgwd3 the amount of leaf starch was constantly higher than wild type during the diurnal cycle. Compared with wild-type leaf starch, the level of C-3 phosphorylation of the glucosyl moiety of starch in this mutant was reduced. Taken together, these data indicate that the C-3 linked phospho-ester in starch plays a so far unnoticed specific role in the degradation of transitory starch.
展开
DOI：
10.1111/j.1365-313X.2004.02322.x
被引量：
年份：
2010
相似文献
参考文献
引证文献
来源期刊
引用走势
辅助模式
引用
文献可以批量引用啦~
欢迎点我试用！
