Molecular Genetic Analysis of Glucan Branching Enzymes from Plants and Bacteria in Arabidopsis Reveals Marked Differences in Their Functions and Capacity to Mediate Starch Granule Formation
| Autor: | Florence Meier, Sebastian Streb, Kuan-Jen Lu, Barbara Pfister, Samuel C. Zeeman |
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| Rok vydání: | 2015 |
| Předmět: |
0106 biological sciences
Physiology Starch Research Articles - Focus Issue Arabidopsis Plant Science 01 natural sciences Zea mays 03 medical and health sciences chemistry.chemical_compound Species Specificity Gene Expression Regulation Plant Genetics Glycogen branching enzyme Escherichia coli Glucans 030304 developmental biology Glucan Solanum tuberosum chemistry.chemical_classification 0303 health sciences biology Glycogen Escherichia coli Proteins fungi food and beverages biology.organism_classification Plants Genetically Modified Starch production Complementation chemistry Biochemistry Amylopectin biology.protein 010606 plant biology & botany |
| Zdroj: | Plant physiology. 169(3) |
| ISSN: | 1532-2548 |
| Popis: | The major component of starch is the branched glucan amylopectin, the branching pattern of which is one of the key factors determining its ability to form semicrystalline starch granules. Here, we investigated the functions of different branching enzyme (BE) types by expressing proteins from maize (Zea mays BE2a), potato (Solanum tuberosum BE1), and Escherichia coli (glycogen BE [EcGLGB]) in Arabidopsis (Arabidopsis thaliana) mutant plants that are deficient in their endogenous BEs and therefore, cannot make starch. The expression of each of these three BE types restored starch biosynthesis to differing degrees. Full complementation was achieved using the class II BE ZmBE2a, which is most similar to the two endogenous Arabidopsis isoforms. Expression of the class I BE from potato, StBE1, resulted in partial complementation and high amylose starch. Expression of the glycogen BE EcGLGB restored only minimal amounts of starch production, which had unusual chain length distribution, branch point distribution, and granule morphology. Nevertheless, each type of BE together with the starch synthases and debranching enyzmes were able to create crystallization-competent amylopectin polymers. These data add to the knowledge of how the properties of the BE influence the final composition of starch and fine structure of amylopectin. |
| Databáze: | OpenAIRE |
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