Oligosaccharide Binding in Escherichia coli Glycogen Synthase
| Autor: | Lei Feng, Alejandra Yep, Fang Sheng, Jack Preiss, James H. Geiger |
|---|---|
| Rok vydání: | 2009 |
| Předmět: |
chemistry.chemical_classification
Binding Sites Glycogen biology Escherichia coli Proteins Molecular Sequence Data Oligosaccharides Oligosaccharide Crystallography X-Ray Biochemistry Catalysis Substrate Specificity chemistry.chemical_compound Glycogen Synthase chemistry Oligosaccharide binding Escherichia coli biology.protein Glycogen branching enzyme Transferase Amino Acid Sequence Binding site Glycogen synthase Starch synthase |
| Zdroj: | Biochemistry. 48:10089-10097 |
| ISSN: | 1520-4995 0006-2960 |
| DOI: | 10.1021/bi900916t |
| Popis: | Glycogen/starch synthase elongates glucan chains and is the key enzyme in the synthesis of glycogen in bacteria and starch in plants. Cocrystallization of Escherichia coli wild-type glycogen synthase (GS) with substrate ADPGlc and the glucan acceptor mimic HEPPSO produced a closed form of GS and suggests that domain-domain closure accompanies glycogen synthesis. Cocrystallization of the inactive GS mutant E377A with substrate ADPGlc and oligosaccharide results in the first oligosaccharide-bound glycogen synthase structure. Four bound oligosaccharides are observed, one in the interdomain cleft (G6a) and three on the N-terminal domain surface (G6b, G6c, and G6d). Extending from the center of the enzyme to the interdomain cleft opening, G6a mostly interacts with the highly conserved N-terminal domain residues lining the cleft of GS. The surface-bound oligosaccharides G6c and G6d have less interaction with enzyme and exhibit a more curled, helixlike structural arrangement. The observation that oligosaccharides bind only to the N-terminal domain of GS suggests that glycogen in vivo probably binds to only one side of the enzyme to ensure unencumbered interdomain movement, which is required for efficient, continuous glucan-chain synthesis. |
| Databáze: | OpenAIRE |
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