A Bacterial Glucanotransferase Can Replace the Complex Maltose Metabolism Required for Starch to Sucrose Conversion in Leaves at Night*
| Autor: | Julia Smirnova, Darrell Cockburn, Martin Steup, Oliver Ebenhöh, William G.T. Willats, Alison M. Smith, Robert A. Field, Henriette L. Pedersen, Birte Svensson, Martin Rejzek, Christian Ruzanski, Marilyn J. Pike |
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| Jazyk: | angličtina |
| Rok vydání: | 2013 |
| Předmět: |
Sucrose
Starch Degradation Starch Arabidopsis Plant Biology Oligosaccharides Maltose Metabolism Biochemistry Oligosaccharide Substrate Specificity chemistry.chemical_compound Cytosol chemistry.chemical_classification Metabolic Regulation Plant Biochemistry Escherichia coli Proteins food and beverages Darkness Plants Genetically Modified Recombinant Proteins Phenotype Leaf Cell Glucosyltransferases Carbohydrate Metabolism Computer Modeling macromolecular substances Biology Buffers Evolution Molecular Glycogen phosphorylase Structure-Activity Relationship Escherichia coli Metabolomics Hexose Maltose Molecular Biology Glucanotransferase Institut für Biochemie und Biologie Glucan fungi Cell Biology Protein Structure Tertiary carbohydrates (lipids) Plant Leaves Enzyme chemistry Mutation |
| Zdroj: | The Journal of Biological Chemistry Ruzanski, C, Smirnova, J, Rejzek, M, Cockburn, D, Pedersen, H L, Pike, M, Willats, W G T, Svensson, B, Steup, M, Ebenhöh, O, Smith, A M & Field, R A 2013, ' A Bacterial Glucanotransferase Can Replace the Complex Maltose Metabolism Required for Starch to Sucrose Conversion in Leaves at Night ', Journal of Biological Chemistry, vol. 288, no. 40, pp. 2028581-28598 . https://doi.org/10.1074/jbc.M113.497867 |
| ISSN: | 1083-351X 0021-9258 |
| DOI: | 10.1074/jbc.M113.497867 |
| Popis: | Background: Maltose metabolism during leaf starch degradation requires a multidomain glucanotransferase and a complex polysaccharide. Results: A conventional bacterial glucanotransferase rescues an Arabidopsis mutant lacking the multidomain glucanotransferase. Conclusion: Both the plant glucanotransferase-polysaccharide couple and the bacterial enzyme provide a glucosyl buffer in the starch degradation pathway. Significance: New light is shed on the regulation and evolution of maltose metabolism. Controlled conversion of leaf starch to sucrose at night is essential for the normal growth of Arabidopsis. The conversion involves the cytosolic metabolism of maltose to hexose phosphates via an unusual, multidomain protein with 4-glucanotransferase activity, DPE2, believed to transfer glucosyl moieties to a complex heteroglycan prior to their conversion to hexose phosphate via a cytosolic phosphorylase. The significance of this complex pathway is unclear; conversion of maltose to hexose phosphate in bacteria proceeds via a more typical 4-glucanotransferase that does not require a heteroglycan acceptor. It has recently been suggested that DPE2 generates a heterogeneous series of terminal glucan chains on the heteroglycan that acts as a “glucosyl buffer” to ensure a constant rate of sucrose synthesis in the leaf at night. Alternatively, DPE2 and/or the heteroglycan may have specific properties important for their function in the plant. To distinguish between these ideas, we compared the properties of DPE2 with those of the Escherichia coli glucanotransferase MalQ. We found that MalQ cannot use the plant heteroglycan as an acceptor for glucosyl transfer. However, experimental and modeling approaches suggested that it can potentially generate a glucosyl buffer between maltose and hexose phosphate because, unlike DPE2, it can generate polydisperse malto-oligosaccharides from maltose. Consistent with this suggestion, MalQ is capable of restoring an essentially wild-type phenotype when expressed in mutant Arabidopsis plants lacking DPE2. In light of these findings, we discuss the possible evolutionary origins of the complex DPE2-heteroglycan pathway. |
| Databáze: | OpenAIRE |
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