4qlb | pdb_00004qlb

Structural Basis for the Recruitment of Glycogen Synthase by Glycogenin

spinqualitylabelsall models 4qlb, resolution 2.60Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4qlb is a 8 chain structure with sequence from Caeel. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: GOL, SO4 Related: 3naz, 3nb0 Gene: gsy-1, Y46G5A.31 (CAEEL) Activity: Glycogen(starch) synthase, with EC number 2.4.1.11 Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [GYS_CAEEL] Transfers the glycosyl residue from UDPG to the non-reducing end of alpha-1,4-glucan. Publication Abstract from PubMed Glycogen is a primary form of energy storage in eukaryotes that is essential for glucose homeostasis. The glycogen polymer is synthesized from glucose through the cooperative action of glycogen synthase (GS), glycogenin (GN), and glycogen branching enzyme and forms particles that range in size from 10 to 290 nm. GS is regulated by allosteric activation upon glucose-6-phosphate binding and inactivation by phosphorylation on its N- and C-terminal regulatory tails. GS alone is incapable of starting synthesis of a glycogen particle de novo, but instead it extends preexisting chains initiated by glycogenin. The molecular determinants by which GS recognizes self-glucosylated GN, the first step in glycogenesis, are unknown. We describe the crystal structure of Caenorhabditis elegans GS in complex with a minimal GS targeting sequence in GN and show that a 34-residue region of GN binds to a conserved surface on GS that is distinct from previously characterized allosteric and binding surfaces on the enzyme. The interaction identified in the GS-GN costructure is required for GS-GN interaction and for glycogen synthesis in a cell-free system and in intact cells. The interaction of full-length GS-GN proteins is enhanced by an avidity effect imparted by a dimeric state of GN and a tetrameric state of GS. Finally, the structure of the N- and C-terminal regulatory tails of GS provide a basis for understanding phosphoregulation of glycogen synthesis. These results uncover a central molecular mechanism that governs glycogen metabolism. Structural basis for the recruitment of glycogen synthase by glycogenin.,Zeqiraj E, Tang X, Hunter RW, Garcia-Rocha M, Judd A, Deak M, von Wilamowitz-Moellendorff A, Kurinov I, Guinovart JJ, Tyers M, Sakamoto K, Sicheri F Proc Natl Acad Sci U S A. 2014 Jun 30. pii: 201402926. PMID:24982189 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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