Structural analysis and reaction mechanism of the disproportionating enzyme (D‐enzyme) from potato
Autor: | Hideaki Unno, Atsushi Nakagawa, Takeshi Takaha, Kayo Imamura, Masami Kusunoki, Shinichi Kitamura, Takanori Matsuura |
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Jazyk: | angličtina |
Rok vydání: | 2020 |
Předmět: |
Reaction mechanism
Starch Full‐Length Papers Biochemistry Catalysis 03 medical and health sciences Hydrolysis chemistry.chemical_compound Protein Domains medicine Molecular Biology 030304 developmental biology Acarbose Plant Proteins Solanum tuberosum chemistry.chemical_classification 0303 health sciences Chemistry 030302 biochemistry & molecular biology fungi Substrate (chemistry) food and beverages Glycogen Debranching Enzyme System Combinatorial chemistry Enzyme Covalent bond medicine.drug |
Zdroj: | Protein Sci |
Popis: | Starch produced by plants is a stored form of energy and is an important dietary source of calories for humans and domestic animals. Disproportionating enzyme (D-enzyme) catalyzes intramolecular and intermolecular transglycosylation reactions of α-1, 4-glucan. D-enzyme is essential in starch metabolism in the potato. We present the crystal structures of potato D-enzyme, including two different types of complex structures: a primary Michaelis complex (substrate binding mode) for 26-meric cycloamylose (CA26) and a covalent intermediate for acarbose. Our study revealed that the acarbose and CA26 reactions catalyzed by potato D-enzyme involve the formation of a covalent intermediate with the donor substrate. HPAEC of reaction substrates and products revealed the activity of the potato D-enzyme on acarbose and CA26 as donor substrates. The structural and chromatography analyses provide insight into the mechanism of the coupling reaction of CA and glucose catalyzed by the potato D-enzyme. The enzymatic reaction mechanism does not involve residual hydrolysis. This could be particularly useful in preventing unnecessary starch degradation leading to reduced crop productivity. Optimization of this mechanism would be important for improvements of starch storage and productivity in crops. |
Databáze: | OpenAIRE |
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