4hln

Structure of barley starch synthase I in complex with maltooligosaccharide

spinqualitylabelsall models 4hln, resolution 2.70Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4hln is a 1 chain structure with sequence from Hordeum vulgare. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.7Å Ligands: GLC Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function Q9M5A3_HORVU Publication Abstract from PubMed Starch, a polymer of glucose, is the major source of calories in the human diet. It has numerous industrial uses, including as a raw material for the production of first-generation bioethanol. Several classes of enzymes take part in starch biosynthesis, of which starch synthases (SSs) carry out chain elongation of both amylose and amylopectin. Plants have five classes of SS, each with different roles. The products of the reaction of SS are well known, but details of the reaction mechanism remain obscure and even less is known of how different SSs select different substrates for elongation, how they compete with each other and how their activities are regulated. Here, the first crystal structure of a soluble starch synthase is presented: that of starch synthase I (SSI) from barley refined to 2.7 A resolution. The structure captures an open conformation of the enzyme with a surface-bound maltooligosaccharide and a disulfide bridge that precludes formation of the active site. The maltooligosaccharide-binding site is involved in substrate recognition, while the disulfide bridge is reflective of redox regulation of SSI. Activity measurements on several SSI mutants supporting these roles are also presented. Structure of starch synthase I from barley: insight into regulatory mechanisms of starch synthase activity.,Cuesta-Seijo JA, Nielsen MM, Marri L, Tanaka H, Beeren SR, Palcic MM Acta Crystallogr D Biol Crystallogr. 2013 Jun;69(Pt 6):1013-25. doi:, 10.1107/S090744491300440X. Epub 2013 May 14. PMID:23695246 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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