2bfw

From Proteopedia

Revision as of 15:31, 5 November 2007

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 with SO4 and ACT as ligands. Active as Starch synthase, with EC number 2.4.1.21 Structure known Active Site: AC1. 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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