2bfw
From Proteopedia
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| , resolution 1.80Å | |||||||
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| Sites: | |||||||
| Ligands: | and | ||||||
| Activity: | Starch synthase, with EC number 2.4.1.21 | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
STRUCTURE OF THE C DOMAIN OF GLYCOGEN SYNTHASE FROM PYROCOCCUS ABYSSI
Overview
Glycogen and starch synthases are retaining glycosyltransferases that catalyze the transfer of glucosyl residues to the non-reducing end of a growing alpha-1,4-glucan chain, a central process of the carbon/energy metabolism present in almost all living organisms. The crystal structure of the glycogen synthase from Pyrococcus abyssi, the smallest known member of this family of enzymes, revealed that its subunits possess a fold common to other glycosyltransferases, a pair of beta/alpha/beta Rossmann fold-type domains with the catalytic site at their interface. Nevertheless, the archaeal enzyme presents an unprecedented homotrimeric molecular arrangement both in solution, as determined by analytical ultracentrifugation, and in the crystal. The C-domains are not involved in intersubunit interactions of the trimeric molecule, thus allowing for movements, likely required for catalysis, across the narrow hinge that connects the N- and C-domains. The radial disposition of the subunits confers on the molecule a distinct triangular shape, clearly visible with negative staining electron microscopy, in which the upper and lower faces present a sharp asymmetry. Comparison of bacterial and eukaryotic glycogen synthases, which use, respectively, ADP or UDP glucose as donor substrates, with the archaeal enzyme, which can utilize both molecules, allowed us to propose the residues that determine glucosyl donor specificity.
About this Structure
2BFW is a Single protein structure of sequence from Pyrococcus abyssi. Full crystallographic information is available from OCA.
Reference
Crystal structure of an archaeal glycogen synthase: insights into oligomerization and substrate binding of eukaryotic glycogen synthases., Horcajada C, Guinovart JJ, Fita I, Ferrer JC, J Biol Chem. 2006 Feb 3;281(5):2923-31. Epub 2005 Nov 29. PMID:16319074
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