Phosphorylation of C6‐ and C3‐positions of glucosyl residues in starch is catalysed by distinct dikinases

Ritte, Gerhard; Heydenreich, Matthias; Mahlow, Sebastian; Haebel, Sophie; Kötting, Oliver; Steup, Martin

doi:10.1016/j.febslet.2006.07.085

Cited by 171 publications

(172 citation statements)

References 19 publications

Supporting

Mentioning

164

Contrasting

Unclassified

Order By: Relevance

“…Finally, R1 was identified as a glucan, water dikinase (GWD) that selectively phosphorylates amylopectin-related glucosyl residues in the C6 position (Ritte et al, 2002(Ritte et al, , 2006. A second dikinase (designated PWD) has also been described that catalyzes the phosphorylation of glucosyl residues in the C3 position (Baunsgaard et al, 2005;Kö tting et al, 2005;Ritte et al, 2006). However, at a mechanistic level, it remained unclear how phosphorylation affects starch turnover.…”

Section: Discussionmentioning

confidence: 99%

“…However, the two plastidial starch-phosphorylating enzymes, i.e. glucan, water dikinase (GWD, EC 2.7.9.4; Ritte et al, 2002Ritte et al, , 2006 and phosphoglucan, water dikinase (PWD, EC 2.7.9.5; Kö tting et al, 2005) display significant activities with granular starch. GWD and PWD selectively catalyze phosphorylation of the C6 and C3 positions, respectively, of glucosyl residues within amylopectin molecules, and are both required for the normal metabolism of transitory starch and for development of the entire plant as well (Baunsgaard et al, 2005;Kö tting et al, 2005;Yu et al, 2001).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Glucan, water dikinase phosphorylates crystalline maltodextrins and thereby initiates solubilization

Hejazi¹,

Fettke

Haebel

et al. 2008

The Plant Journal

Self Cite

View full text Add to dashboard Cite

SummaryStarch phosphorylation by glucan, water dikinase (GWD; EC 2.7.9.4) is an essential step in the breakdown of native starch particles, but the underlying mechanisms have remained obscure. In this paper, the initial reactions of starch degradation were analyzed using crystallized maltodextrins as model carbohydrates. As revealed by X-ray diffraction analysis, the crystallized maltodextrins represent the B-type starch allomorph. Recombinant GWD phosphorylated crystalline maltodextrins with a high specific activity (55-60 nmol mg )1 protein min )1 ), but exhibited very little activity with the same maltodextrins that had been solubilized by heat treatment. Recombinant phosphoglucan, water dikinase (PWD; EC 2.7.9.5) utilized the crystalline maltodextrins only when pre-phosphorylated by GWD. Phosphorylation of crystalline maltodextrins, as catalyzed by GWD, initiated solubilization of neutral as well as phosphorylated glucans. In both the insoluble and the soluble state, mono-, di-and triphosphorylated a-glucans were observed, with wide and overlapping ranges of degree of polymerization. Thus, the substrate specificity of the GWD is defined by the physical arrangement of a-glucans rather than by structural parameters, such as the distribution of branching points or degree of polymerization. Unlike GWD and PWD, recombinant b-amylase isozyme 3 (BAM3), which has been shown to be essential for plastidial starch degradation, preferentially degraded soluble maltodextrins rather than crystallized glucans. In summary, two conclusions were reached. Firstly, carbohydrate targets of GWD are primarily defined by the molecular order of glucan helices. Secondly, GWD-catalyzed phosphorylation mediates the phase transition of glucans from a highly ordered to a less ordered and hydrated state.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Glucan, water dikinase phosphorylates crystalline maltodextrins and thereby initiates solubilization

Hejazi¹,

Fettke

Haebel

et al. 2008

The Plant Journal

Self Cite

View full text Add to dashboard Cite

show abstract

“…For example, the enzymes mediating the phosphorylation and dephosphorylation of starch, a process that precedes its degradation by amylases, may be required for osmotic stress-induced degradation as well as for normal nighttime degradation (Yano et al, 2005;Silver et al, 2014;Kötting et al, 2010). However, GWD, which phosphorylates the C6-position of glucosyl residues (Ritte et al, 2006), was reported to be involved in the cold-induced development of freezing tolerance (Yano et al, 2005), similar to BAM3 (Kaplan and Guy, 2004). Thus, it is plausible that a certain degree of subfunctionalization also exists within the enzymes of glucan phosphorylation, with GWD required for the mobilization of starch under cold stress, and PWD, which phosphorylates the C3 positions, required for the activation of starch degradation under osmotic stress.…”

Section: Differential Regulation and Isoform Subfunctionalization Defmentioning

confidence: 99%

“…Transitory starch degradation at night begins with the phosphorylation of the glucan chains by glucan, water dikinase (GWD) and phosphoglucan, water dikinase (PWD) (Ritte et al, 2006). The chains are then simultaneously degraded by a set of glucanhydrolyzing enzymes (including b-amylases [BAM], a-amylases [AMY], and debranching enzymes) and dephosphorylated by phosphoglucan phosphatases (Streb and Zeeman, 2012).…”

Section: Introductionmentioning

confidence: 99%

Regulation of Leaf Starch Degradation by Abscisic Acid Is Important for Osmotic Stress Tolerance in Plants

et al. 2016

View full text Add to dashboard Cite

Starch serves functions that range over a timescale of minutes to years, according to the cell type from which it is derived. In guard cells, starch is rapidly mobilized by the synergistic action of b-AMYLASE1 (BAM1) and a-AMYLASE3 (AMY3) to promote stomatal opening. In the leaves, starch typically accumulates gradually during the day and is degraded at night by BAM3 to support heterotrophic metabolism. During osmotic stress, starch is degraded in the light by stress-activated BAM1 to release sugar and sugar-derived osmolytes. Here, we report that AMY3 is also involved in stress-induced starch degradation. Recently isolated Arabidopsis thaliana amy3 bam1 double mutants are hypersensitive to osmotic stress, showing impaired root growth. amy3 bam1 plants close their stomata under osmotic stress at similar rates as the wild type but fail to mobilize starch in the leaves. 14 C labeling showed that amy3 bam1 plants have reduced carbon export to the root, affecting osmolyte accumulation and root growth during stress. Using genetic approaches, we further demonstrate that abscisic acid controls the activity of BAM1 and AMY3 in leaves under osmotic stress through the AREB/ABF-SnRK2 kinase-signaling pathway. We propose that differential regulation and isoform subfunctionalization define starch-adaptive plasticity, ensuring an optimal carbon supply for continued growth under an ever-changing environment.

show abstract

“…Two enzymes that catalyze starch phosphorylation, glucan, water dikinase (GWD) and phosphoglucan, water dikinase (PWD; also called GWD3), are required for normal rates of starch degradation (Yu et al, 2001;Ritte et al, 2002;Baunsgaard et al, 2005;Kö tting et al, 2005;Ritte et al, 2006). Mutants lacking either enzyme grow slowly, have reduced rates of starch degradation, and display starch-excess phenotypes; that is, they retain high levels of starch in their leaves at the end of the night.…”

mentioning

confidence: 99%

A Putative Phosphatase, LSF1, Is Required for Normal Starch Turnover in Arabidopsis Leaves

et al. 2009

Self Cite

View full text Add to dashboard Cite

A putative phosphatase, LSF1 (for LIKE SEX4; previously PTPKIS2), is closely related in sequence and structure to STARCH-EXCESS4 (SEX4), an enzyme necessary for the removal of phosphate groups from starch polymers during starch degradation in Arabidopsis (Arabidopsis thaliana) leaves at night. We show that LSF1 is also required for starch degradation: lsf1 mutants, like sex4 mutants, have substantially more starch in their leaves than wild-type plants throughout the diurnal cycle. LSF1 is chloroplastic and is located on the surface of starch granules. lsf1 and sex4 mutants show similar, extensive changes relative to wild-type plants in the expression of sugar-sensitive genes. However, although LSF1 and SEX4 are probably both involved in the early stages of starch degradation, we show that LSF1 neither catalyzes the same reaction as SEX4 nor mediates a sequential step in the pathway. Evidence includes the contents and metabolism of phosphorylated glucans in the single mutants. The sex4 mutant accumulates soluble phospho-oligosaccharides undetectable in wild-type plants and is deficient in a starch granuledephosphorylating activity present in wild-type plants. The lsf1 mutant displays neither of these phenotypes. The phenotype of the lsf1/sex4 double mutant also differs from that of both single mutants in several respects. We discuss the possible role of the LSF1 protein in starch degradation.

show abstract

Phosphorylation of C6‐ and C3‐positions of glucosyl residues in starch is catalysed by distinct dikinases

Cited by 171 publications

References 19 publications

Glucan, water dikinase phosphorylates crystalline maltodextrins and thereby initiates solubilization

Glucan, water dikinase phosphorylates crystalline maltodextrins and thereby initiates solubilization

Regulation of Leaf Starch Degradation by Abscisic Acid Is Important for Osmotic Stress Tolerance in Plants

A Putative Phosphatase, LSF1, Is Required for Normal Starch Turnover in Arabidopsis Leaves

Contact Info

Product

Resources

About