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Liu QH, Tang JW, Wen PB, Wang MM, Zhang X, Wang L. From Prokaryotes to Eukaryotes: Insights Into the Molecular Structure of Glycogen Particles. Front Mol Biosci 2021; 8:673315. [PMID: 33996916 PMCID: PMC8116748 DOI: 10.3389/fmolb.2021.673315] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Accepted: 04/07/2021] [Indexed: 12/25/2022] Open
Abstract
Glycogen is a highly-branched polysaccharide that is widely distributed across the three life domains. It has versatile functions in physiological activities such as energy reserve, osmotic regulation, blood glucose homeostasis, and pH maintenance. Recent research also confirms that glycogen plays important roles in longevity and cognition. Intrinsically, glycogen function is determined by its structure that has been intensively studied for many years. The recent association of glycogen α-particle fragility with diabetic conditions further strengthens the importance of glycogen structure in its function. By using improved glycogen extraction procedures and a series of advanced analytical techniques, the fine molecular structure of glycogen particles in human beings and several model organisms such as Escherichia coli, Caenorhabditis elegans, Mus musculus, and Rat rattus have been characterized. However, there are still many unknowns about the assembly mechanisms of glycogen particles, the dynamic changes of glycogen structures, and the composition of glycogen associated proteins (glycogen proteome). In this review, we explored the recent progresses in glycogen studies with a focus on the structure of glycogen particles, which may not only provide insights into glycogen functions, but also facilitate the discovery of novel drug targets for the treatment of diabetes mellitus.
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Affiliation(s)
- Qing-Hua Liu
- State Key Laboratory of Quality Research in Chinese Medicines, Macau University of Science and Technology, Macau, China.,Faculty of Chinese Medicine, Macau University of Science and Technology, Macau, China
| | - Jia-Wei Tang
- Department of Bioinformatics, School of Medical Informatics and Engineering, Xuzhou Medical University, Xuzhou, China
| | - Peng-Bo Wen
- Department of Bioinformatics, School of Medical Informatics and Engineering, Xuzhou Medical University, Xuzhou, China
| | - Meng-Meng Wang
- Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, School of Pharmacy, Xuzhou Medical University, Xuzhou, China
| | - Xiao Zhang
- Department of Bioinformatics, School of Medical Informatics and Engineering, Xuzhou Medical University, Xuzhou, China
| | - Liang Wang
- Department of Bioinformatics, School of Medical Informatics and Engineering, Xuzhou Medical University, Xuzhou, China.,Jiangsu Key Laboratory of New Drug Research and Clinical Pharmacy, School of Pharmacy, Xuzhou Medical University, Xuzhou, China
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Almodóvar-Payá A, Villarreal-Salazar M, de Luna N, Nogales-Gadea G, Real-Martínez A, Andreu AL, Martín MA, Arenas J, Lucia A, Vissing J, Krag T, Pinós T. Preclinical Research in Glycogen Storage Diseases: A Comprehensive Review of Current Animal Models. Int J Mol Sci 2020; 21:ijms21249621. [PMID: 33348688 PMCID: PMC7766110 DOI: 10.3390/ijms21249621] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 12/11/2020] [Accepted: 12/15/2020] [Indexed: 12/19/2022] Open
Abstract
GSD are a group of disorders characterized by a defect in gene expression of specific enzymes involved in glycogen breakdown or synthesis, commonly resulting in the accumulation of glycogen in various tissues (primarily the liver and skeletal muscle). Several different GSD animal models have been found to naturally present spontaneous mutations and others have been developed and characterized in order to further understand the physiopathology of these diseases and as a useful tool to evaluate potential therapeutic strategies. In the present work we have reviewed a total of 42 different animal models of GSD, including 26 genetically modified mouse models, 15 naturally occurring models (encompassing quails, cats, dogs, sheep, cattle and horses), and one genetically modified zebrafish model. To our knowledge, this is the most complete list of GSD animal models ever reviewed. Importantly, when all these animal models are analyzed together, we can observe some common traits, as well as model specific differences, that would be overlooked if each model was only studied in the context of a given GSD.
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Affiliation(s)
- Aitana Almodóvar-Payá
- Mitochondrial and Neuromuscular Disorders Unit, Vall d’Hebron Institut de Recerca, Universitat Autònoma de Barcelona, 08035 Barcelona, Spain; (A.A.-P.); (M.V.-S.); (A.R.-M.)
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), 28029 Madrid, Spain; (N.d.L.); (G.N.-G.); (M.A.M.); (J.A.)
| | - Mónica Villarreal-Salazar
- Mitochondrial and Neuromuscular Disorders Unit, Vall d’Hebron Institut de Recerca, Universitat Autònoma de Barcelona, 08035 Barcelona, Spain; (A.A.-P.); (M.V.-S.); (A.R.-M.)
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), 28029 Madrid, Spain; (N.d.L.); (G.N.-G.); (M.A.M.); (J.A.)
| | - Noemí de Luna
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), 28029 Madrid, Spain; (N.d.L.); (G.N.-G.); (M.A.M.); (J.A.)
- Laboratori de Malalties Neuromusculars, Institut de Recerca Hospital de la Santa Creu i Sant Pau, Universitat Autònoma de Barcelona, 08041 Barcelona, Spain
| | - Gisela Nogales-Gadea
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), 28029 Madrid, Spain; (N.d.L.); (G.N.-G.); (M.A.M.); (J.A.)
- Grup de Recerca en Malalties Neuromusculars i Neuropediàtriques, Department of Neurosciences, Institut d’Investigacio en Ciencies de la Salut Germans Trias i Pujol i Campus Can Ruti, Universitat Autònoma de Barcelona, 08916 Badalona, Spain
| | - Alberto Real-Martínez
- Mitochondrial and Neuromuscular Disorders Unit, Vall d’Hebron Institut de Recerca, Universitat Autònoma de Barcelona, 08035 Barcelona, Spain; (A.A.-P.); (M.V.-S.); (A.R.-M.)
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), 28029 Madrid, Spain; (N.d.L.); (G.N.-G.); (M.A.M.); (J.A.)
| | - Antoni L. Andreu
- EATRIS, European Infrastructure for Translational Medicine, 1081 HZ Amsterdam, The Netherlands;
| | - Miguel Angel Martín
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), 28029 Madrid, Spain; (N.d.L.); (G.N.-G.); (M.A.M.); (J.A.)
- Mitochondrial and Neuromuscular Diseases Laboratory, 12 de Octubre Hospital Research Institute (i+12), 28041 Madrid, Spain
| | - Joaquin Arenas
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), 28029 Madrid, Spain; (N.d.L.); (G.N.-G.); (M.A.M.); (J.A.)
- Mitochondrial and Neuromuscular Diseases Laboratory, 12 de Octubre Hospital Research Institute (i+12), 28041 Madrid, Spain
| | - Alejandro Lucia
- Faculty of Sport Sciences, European University, 28670 Madrid, Spain;
| | - John Vissing
- Copenhagen Neuromuscular Center, Department of Neurology, Rigshospitalet, University of Copenhagen, DK-2100 Copenhagen, Denmark; (J.V.); (T.K.)
| | - Thomas Krag
- Copenhagen Neuromuscular Center, Department of Neurology, Rigshospitalet, University of Copenhagen, DK-2100 Copenhagen, Denmark; (J.V.); (T.K.)
| | - Tomàs Pinós
- Mitochondrial and Neuromuscular Disorders Unit, Vall d’Hebron Institut de Recerca, Universitat Autònoma de Barcelona, 08035 Barcelona, Spain; (A.A.-P.); (M.V.-S.); (A.R.-M.)
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), 28029 Madrid, Spain; (N.d.L.); (G.N.-G.); (M.A.M.); (J.A.)
- Correspondence: ; Tel.: +34-934894057
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Visuttijai K, Hedberg-Oldfors C, Thomsen C, Glamuzina E, Kornblum C, Tasca G, Hernandez-Lain A, Sandstedt J, Dellgren G, Roach P, Oldfors A. Glycogenin is Dispensable for Glycogen Synthesis in Human Muscle, and Glycogenin Deficiency Causes Polyglucosan Storage. J Clin Endocrinol Metab 2020; 105:5599738. [PMID: 31628455 PMCID: PMC7046021 DOI: 10.1210/clinem/dgz075] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Accepted: 10/02/2019] [Indexed: 02/06/2023]
Abstract
CONTEXT Glycogenin is considered to be an essential primer for glycogen biosynthesis. Nevertheless, patients with glycogenin-1 deficiency due to biallelic GYG1 (NM_004130.3) mutations can store glycogen in muscle. Glycogenin-2 has been suggested as an alternative primer for glycogen synthesis in patients with glycogenin-1 deficiency. OBJECTIVE The objective of this article is to investigate the importance of glycogenin-1 and glycogenin-2 for glycogen synthesis in skeletal and cardiac muscle. DESIGN, SETTING, AND PATIENTS Glycogenin-1 and glycogenin-2 expression was analyzed by Western blot, mass spectrometry, and immunohistochemistry in liver, heart, and skeletal muscle from controls and in skeletal and cardiac muscle from patients with glycogenin-1 deficiency. RESULTS Glycogenin-1 and glycogenin-2 both were found to be expressed in the liver, but only glycogenin-1 was identified in heart and skeletal muscle from controls. In patients with truncating GYG1 mutations, neither glycogenin-1 nor glycogenin-2 was expressed in skeletal muscle. However, nonfunctional glycogenin-1 but not glycogenin-2 was identified in cardiac muscle from patients with cardiomyopathy due to GYG1 missense mutations. By immunohistochemistry, the mutated glycogenin-1 colocalized with the storage of glycogen and polyglucosan in cardiomyocytes. CONCLUSIONS Glycogen can be synthesized in the absence of glycogenin, and glycogenin-1 deficiency is not compensated for by upregulation of functional glycogenin-2. Absence of glycogenin-1 leads to the focal accumulation of glycogen and polyglucosan in skeletal muscle fibers. Expression of mutated glycogenin-1 in the heart is deleterious, and it leads to storage of abnormal glycogen and cardiomyopathy.
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Affiliation(s)
- Kittichate Visuttijai
- Department of Pathology and Genetics, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Carola Hedberg-Oldfors
- Department of Pathology and Genetics, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Christer Thomsen
- Department of Pathology and Genetics, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
| | - Emma Glamuzina
- National Metabolic Service, Starship Children’s Hospital, Auckland, New Zealand
| | | | - Giorgio Tasca
- Unità Operativa Complessa di Neurologia, Dipartimento di Scienze dell’Invecchiamento, Neurologiche, Ortopediche e della Testa-Collo, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy
| | | | - Joakim Sandstedt
- Department of Clinical Chemistry, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden
| | - Göran Dellgren
- Department of Cardiothoracic Surgery, Sahlgrenska University Hospital, Gothenburg, Sweden
| | - Peter Roach
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana
| | - Anders Oldfors
- Department of Pathology and Genetics, Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden
- Correspondence and Reprint Requests: Anders Oldfors, Department of Pathology and Genetics, Institute of Biomedicine, University of Gothenburg, Sahlgrenska University Hospital, 41345, Gothenburg, Sweden. E-mail:
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From the seminal discovery of proteoglycogen and glycogenin to emerging knowledge and research on glycogen biology. Biochem J 2019; 476:3109-3124. [DOI: 10.1042/bcj20190441] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Revised: 09/10/2019] [Accepted: 10/14/2019] [Indexed: 11/17/2022]
Abstract
AbstractAlthough the discovery of glycogen in the liver, attributed to Claude Bernard, happened more than 160 years ago, the mechanism involved in the initiation of glucose polymerization remained unknown. The discovery of glycogenin at the core of glycogen's structure and the initiation of its glucopolymerization is among one of the most exciting and relatively recent findings in Biochemistry. This review focuses on the initial steps leading to the seminal discoveries of proteoglycogen and glycogenin at the beginning of the 1980s, which paved the way for subsequent foundational breakthroughs that propelled forward this new research field. We also explore the current, as well as potential, impact this research field is having on human health and disease from the perspective of glycogen storage diseases. Important new questions arising from recent studies, their links to basic mechanisms involved in the de novo glycogen biogenesis, and the pervading presence of glycogenin across the evolutionary scale, fueled by high throughput -omics technologies, are also addressed.
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Li B, Meng J, Li L, Liu S, Wang T, Zhang G. Identification and Functional Characterization of the Glycogen Synthesis Related Gene Glycogenin in Pacific Oysters (Crassostrea gigas). JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2017; 65:7764-7773. [PMID: 28780871 DOI: 10.1021/acs.jafc.7b02720] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
High glycogen levels in the Pacific oyster (Crassostrea gigas) contribute to its flavor, quality, and hardiness. Glycogenin (CgGN) is the priming glucosyltransferase that initiates glycogen biosynthesis. We characterized the full sequence and function of C. gigas CgGN. Three CgGN isoforms (CgGN-α, β, and γ) containing alternative exon regions were isolated. CgGN expression varied seasonally in the adductor muscle and gonadal area and was the highest in the adductor muscle. Autoglycosylation of CgGN can interact with glycogen synthase (CgGS) to complete glycogen synthesis. Subcellular localization analysis showed that CgGN isoforms and CgGS were located in the cytoplasm. Additionally, a site-directed mutagenesis experiment revealed that the Tyr200Phe and Tyr202Phe mutations could affect CgGN autoglycosylation. This is the first study of glycogenin function in marine bivalves. These findings will improve our understanding of glycogen synthesis and accumulation mechanisms in mollusks. The data are potentially useful for breeding high-glycogen oysters.
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Affiliation(s)
- Busu Li
- University of Chinese Academy of Sciences , Beijing 100049, China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology , Qingdao 266000, China
| | - Jie Meng
- Laboratory for Marine Fisheries and Aquaculture, Qingdao National Laboratory for Marine Science and Technology , Qingdao 266000, Shandong, China
| | - Li Li
- Laboratory for Marine Fisheries and Aquaculture, Qingdao National Laboratory for Marine Science and Technology , Qingdao 266000, Shandong, China
| | - Sheng Liu
- University of Chinese Academy of Sciences , Beijing 100049, China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology , Qingdao 266000, China
| | - Ting Wang
- University of Chinese Academy of Sciences , Beijing 100049, China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology , Qingdao 266000, China
| | - Guofan Zhang
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology , Qingdao 266000, China
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Testoni G, Duran J, García-Rocha M, Vilaplana F, Serrano AL, Sebastián D, López-Soldado I, Sullivan MA, Slebe F, Vilaseca M, Muñoz-Cánoves P, Guinovart JJ. Lack of Glycogenin Causes Glycogen Accumulation and Muscle Function Impairment. Cell Metab 2017; 26:256-266.e4. [PMID: 28683291 DOI: 10.1016/j.cmet.2017.06.008] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Revised: 05/08/2017] [Accepted: 06/13/2017] [Indexed: 11/27/2022]
Abstract
Glycogenin is considered essential for glycogen synthesis, as it acts as a primer for the initiation of the polysaccharide chain. Against expectations, glycogenin-deficient mice (Gyg KO) accumulate high amounts of glycogen in striated muscle. Furthermore, this glycogen contains no covalently bound protein, thereby demonstrating that a protein primer is not strictly necessary for the synthesis of the polysaccharide in vivo. Strikingly, in spite of the higher glycogen content, Gyg KO mice showed lower resting energy expenditure and less resistance than control animals when subjected to endurance exercise. These observations can be attributed to a switch of oxidative myofibers toward glycolytic metabolism. Mice overexpressing glycogen synthase in the muscle showed similar alterations, thus indicating that this switch is caused by the excess of glycogen. These results may explain the muscular defects of GSD XV patients, who lack glycogenin-1 and show high glycogen accumulation in muscle.
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Affiliation(s)
- Giorgia Testoni
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona 08028, Spain
| | - Jordi Duran
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona 08028, Spain; Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Madrid 28029, Spain
| | - Mar García-Rocha
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona 08028, Spain
| | - Francisco Vilaplana
- Division of Glycoscience, School of Biotechnology, KTH Royal Institute of Technology, AlbaNova University Centre, Stockholm 10691, Sweden
| | - Antonio L Serrano
- Cell Biology Group, Department of Experimental and Health Sciences, Pompeu Fabra University (UPF), CIBER on Neurodegenerative diseases (CIBERNED), Barcelona 08003, Spain
| | - David Sebastián
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona 08028, Spain; Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Madrid 28029, Spain; Department of Biochemistry and Molecular Biomedicine, University of Barcelona, Barcelona 08028, Spain
| | - Iliana López-Soldado
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona 08028, Spain; Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Madrid 28029, Spain
| | - Mitchell A Sullivan
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON M5G 1X8, Canada
| | - Felipe Slebe
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona 08028, Spain
| | - Marta Vilaseca
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona 08028, Spain
| | - Pura Muñoz-Cánoves
- Cell Biology Group, Department of Experimental and Health Sciences, Pompeu Fabra University (UPF), CIBER on Neurodegenerative diseases (CIBERNED), Barcelona 08003, Spain; Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona 08010, Spain; Spanish National Center on Cardiovascular Research (CNIC), Madrid 28029, Spain
| | - Joan J Guinovart
- Institute for Research in Biomedicine (IRB Barcelona), The Barcelona Institute of Science and Technology, Barcelona 08028, Spain; Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Madrid 28029, Spain; Department of Biochemistry and Molecular Biomedicine, University of Barcelona, Barcelona 08028, Spain.
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A hemizygous GYG2 mutation and Leigh syndrome: a possible link? Hum Genet 2013; 133:225-34. [DOI: 10.1007/s00439-013-1372-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Accepted: 09/29/2013] [Indexed: 11/26/2022]
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Gibbons BJ, Roach PJ, Hurley TD. Crystal structure of the autocatalytic initiator of glycogen biosynthesis, glycogenin. J Mol Biol 2002; 319:463-77. [PMID: 12051921 DOI: 10.1016/s0022-2836(02)00305-4] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Glycogen is an important storage reserve of glucose present in many organisms, from bacteria to humans. Its biosynthesis is initiated by a specialized protein, glycogenin, which has the unusual property of transferring glucose from UDP-glucose to form an oligosaccharide covalently attached to itself at Tyr194. Glycogen synthase and the branching enzyme complete the synthesis of the polysaccharide. The structure of glycogenin was solved in two different crystal forms. Tetragonal crystals contained a pentamer of dimers in the asymmetric unit arranged in an improper non-crystallographic 10-fold relationship, and orthorhombic crystals contained a monomer in the asymmetric unit that is arranged about a 2-fold crystallographic axis to form a dimer. The structure was first solved to 3.4 A using the tetragonal crystal form and a three-wavelength Se-Met multi-wavelength anomalous diffraction (MAD) experiment. Subsequently, an apo-enzyme structure and a complex between glycogenin and UDP-glucose/Mn2+ were solved by molecular replacement to 1.9 A using the orthorhombic crystal form. Glycogenin contains a conserved DxD motif and an N-terminal beta-alpha-beta Rossmann-like fold that are common to the nucleotide-binding domains of most glycosyltransferases. Although sequence identity amongst glycosyltransferases is minimal, the overall folds are similar. In all of these enzymes, the DxD motif is essential for coordination of the catalytic divalent cation, most commonly Mn2+. We propose a mechanism in which the Mn2+ that associates with the UDP-glucose molecule functions as a Lewis acid to stabilize the leaving group UDP and to facilitate the transfer of the glucose moiety to an intermediate nucleophilic acceptor in the enzyme active site, most likely Asp162. Following transient transfer to Asp162, the glucose moiety is then delivered to the final acceptor, either directly to Tyr194 or to glucose residues already attached to Tyr194. The positioning of the bound UDP-glucose far from Tyr194 in the glycogenin structure raises questions as to the mechanism for the attachment of the first glucose residues. Possibly the initial glucosylation is via inter-dimeric catalysis with an intra-molecular mechanism employed later in oligosaccharide synthesis.
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Affiliation(s)
- Brian J Gibbons
- Department of Biochemistry and Molecular Biology and Center for Diabetes Research, Indiana University School of Medicine, 635 Barnhill Drive Indianapolis, IN 46202-5122, USA
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