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440 a.a.
Key reference
DOI no: 10.1074/jbc.M507394200 J Biol Chem 281:2923-2931 (2006) PubMed id: 16319074
Crystal structure of an archaeal glycogen synthase: insights into oligomerization and substrate binding of eukaryotic glycogen synthases. C.Horcajada, J.J.Guinovart, I.Fita, J.C.Ferrer. ABSTRACT
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.
Literature references that cite this PDB file's key reference
PubMed id Reference
19245651 A.McBride, and D.G.Hardie (2009).
AMP-activated protein kinase--a sensor of glycogen as well as AMP and ATP?Acta Physiol (Oxf), 196, 99.
18205830 C.Goedl, and B.Nidetzky (2008).
The phosphate site of trehalose phosphorylase from Schizophyllum commune probed by site-directed mutagenesis and chemical rescue studies.FEBS J, 275, 903-913.
18518825 L.L.Lairson, B.Henrissat, G.J.Davies, and S.G.Withers (2008).
Glycosyltransferases: structures, functions, and mechanisms.Annu Rev Biochem, 77, 521-555.
17623838 M.V.Busi, N.Palopoli, H.A.Valdez, M.S.Fornasari, N.Z.Wayllace, D.F.Gomez-Casati, G.Parisi, and R.A.Ugalde (2008).
Functional and structural characterization of the catalytic domain of the starch synthase III from Arabidopsis thaliana.Proteins, 70, 31-40.
16627938 S.Trapani, C.Abergel, I.Gutsche, C.Horcajada, I.Fita, and J.Navaza (2006).
Combining experimental data for structure determination of flexible multimeric macromolecules by molecular replacement.Acta Crystallogr D Biol Crystallogr, 62, 467-475. The most recent references are shown first. Citation data come partly from CiteXplore and partly from an automated harvesting procedure. Note that this is likely to be only a partial list as not all journals are covered by either method. However, we are continually building up the citation data so more and more references will be included with time.
