Structure of the polyisoprenyl-phosphate glycosyltransferase GtrB and insights into the mechanism of catalysis
| Autor: | Lawrence Shapiro, Surajit Banerjee, Désirée von Alpen, Qun Liu, Renato Bruni, M. Chiara Manzini, Oliver B. Clarke, Edda Kloppmann, Chijun Li, Chiara Ardiccioni, Burkhard Rost, Filippo Mancia, Heather L. Pond, Brian Kloss, David Tomasek, Ziqiang Guan, Kanagalaghatta R. Rajashankar, Habon Issa |
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| Rok vydání: | 2016 |
| Předmět: |
Models
Molecular 0301 basic medicine Glycosylation Protein Conformation Science General Physics and Astronomy Mannose Protomer Mannosyltransferases Article Gene Expression Regulation Enzymologic General Biochemistry Genetics and Molecular Biology Animals Genetically Modified 03 medical and health sciences chemistry.chemical_compound Protein structure Glycosyltransferase Animals Humans Zebrafish Multidisciplinary biology Endoplasmic reticulum Synechocystis Glycosyltransferases Active site Gene Expression Regulation Bacterial General Chemistry 030104 developmental biology chemistry Biochemistry biology.protein lipids (amino acids peptides and proteins) |
| Zdroj: | Nature Communications, Vol 7, Iss 1, Pp 1-9 (2016) Nature Communications |
| ISSN: | 2041-1723 |
| DOI: | 10.1038/ncomms10175 |
| Popis: | The attachment of a sugar to a hydrophobic polyisoprenyl carrier is the first step for all extracellular glycosylation processes. The enzymes that perform these reactions, polyisoprenyl-glycosyltransferases (PI-GTs) include dolichol phosphate mannose synthase (DPMS), which generates the mannose donor for glycosylation in the endoplasmic reticulum. Here we report the 3.0Å resolution crystal structure of GtrB, a glucose-specific PI-GT from Synechocystis, showing a tetramer in which each protomer contributes two helices to a membrane-spanning bundle. The active site is 15 Å from the membrane, raising the question of how water-soluble and membrane-embedded substrates are brought into apposition for catalysis. A conserved juxtamembrane domain harbours disease mutations, which compromised activity in GtrB in vitro and in human DPM1 tested in zebrafish. We hypothesize a role of this domain in shielding the polyisoprenyl-phosphate for transport to the active site. Our results reveal the basis of PI-GT function, and provide a potential molecular explanation for DPM1-related disease. Polyisoprenyl-glycosyltransferases (PI-GTs) catalyse the addition of sugar to lipid carriers, which is the first step in the production of sugar donors for glycosylation. Here Ardiccioni et al. present the structure of a bacterial PI-GT and propose a mechanistic basis for sugar transfer. |
| Databáze: | OpenAIRE |
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