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Liu X, Zhang P, Gilbert RG. Formation mechanism of α particles in glycogen: Testing the budding hypothesis by Monte-Carlo simulation. Int J Biol Macromol 2024; 263:130332. [PMID: 38401580 DOI: 10.1016/j.ijbiomac.2024.130332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 02/15/2024] [Accepted: 02/19/2024] [Indexed: 02/26/2024]
Abstract
Glycogen, a complex branched glucose polymer and a blood-sugar reservoir in animals, comprises small β particles joined together into composite α particles. In diabetic animals, α particles fragment more easily than those in healthy animals. Finding evidence for or against postulated mechanisms for α-particle formation is thus important for diabetes research. Insight into this is obtained here using Monte-Carlo simulations, including addition and loss of glucose monomer, branching and debranching, based on earlier simulations which were in acceptable agreement with experiment [Zhang et al., Int J Biol Macromolecules 2018, 116, 264]. One postulated mechanism for α-particle formation is "budding": occasionally a glucan chain temporarily protrudes from the particle, and if its growing end is sufficiently far from its parent particle, it propagates to a new linked particle. We tested this by simulations in which an "artificial" bud (a chain extending well outside the average particle radius) is added to a glycogen molecule in a dynamic steady state, and the system allowed to evolve. In some simulations, the particle reached a new steady state having an irregular dumbbell shape: a rudimentary α particle. Thus 'budding' is a possible mechanism for α particles to form. If no simulations had shown this behaviour, it would have refuted the postulate.
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Affiliation(s)
- Xin Liu
- Jiangsu Key Laboratory of Crop Genetics and Physiology, Key Laboratory of Plant Functional Genomics of the Ministry of Education, College of Agriculture, Yangzhou University, Yangzhou 225009, Jiangsu Province, China; Co-Innovation Centre for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou 225009, Jiangsu Province, China; Centre for Nutrition & Food Sciences, Queensland Alliance for Agriculture & Food Innovations (QAAFI), The University of Queensland, QLD 4072, Australia
| | - Peng Zhang
- School of Electronic Engineering, Tongling University, Tongling 244061, PR China
| | - Robert G Gilbert
- Jiangsu Key Laboratory of Crop Genetics and Physiology, Key Laboratory of Plant Functional Genomics of the Ministry of Education, College of Agriculture, Yangzhou University, Yangzhou 225009, Jiangsu Province, China; Co-Innovation Centre for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou 225009, Jiangsu Province, China; Centre for Nutrition & Food Sciences, Queensland Alliance for Agriculture & Food Innovations (QAAFI), The University of Queensland, QLD 4072, Australia.
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2
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Bilyard MK, Bailey HJ, Raich L, Gafitescu MA, Machida T, Iglésias-Fernández J, Lee SS, Spicer CD, Rovira C, Yue WW, Davis BG. Palladium-mediated enzyme activation suggests multiphase initiation of glycogenesis. Nature 2018; 563:235-240. [PMID: 30356213 DOI: 10.1038/s41586-018-0644-7] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2017] [Accepted: 08/31/2018] [Indexed: 11/09/2022]
Abstract
Biosynthesis of glycogen, the essential glucose (and hence energy) storage molecule in humans, animals and fungi1, is initiated by the glycosyltransferase enzyme, glycogenin (GYG). Deficiencies in glycogen formation cause neurodegenerative and metabolic disease2-4, and mouse knockout5 and inherited human mutations6 of GYG impair glycogen synthesis. GYG acts as a 'seed core' for the formation of the glycogen particle by catalysing its own stepwise autoglucosylation to form a covalently bound gluco-oligosaccharide chain at initiation site Tyr 195. Precise mechanistic studies have so far been prevented by an inability to access homogeneous glycoforms of this protein, which unusually acts as both catalyst and substrate. Here we show that unprecedented direct access to different, homogeneously glucosylated states of GYG can be accomplished through a palladium-mediated enzyme activation 'shunt' process using on-protein C-C bond formation. Careful mimicry of GYG intermediates recapitulates catalytic activity at distinct stages, which in turn allows discovery of triphasic kinetics and substrate plasticity in GYG's use of sugar substrates. This reveals a tolerant but 'proof-read' mechanism that underlies the precision of this metabolic process. The present demonstration of direct, chemically controlled access to intermediate states of active enzymes suggests that such ligation-dependent activation could be a powerful tool in the study of mechanism.
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Affiliation(s)
| | - Henry J Bailey
- Structural Genomics Consortium, University of Oxford, Oxford, UK
| | - Lluís Raich
- Departament de Química Inorgànica i Orgànica (Secció de Química Orgànica) and Institut de Química Teòrica i Computacional (IQTC), Universitat de Barcelona, Barcelona, Spain
| | | | - Takuya Machida
- Department of Chemistry, University of Oxford, Oxford, UK
| | - Javier Iglésias-Fernández
- Departament de Química Inorgànica i Orgànica (Secció de Química Orgànica) and Institut de Química Teòrica i Computacional (IQTC), Universitat de Barcelona, Barcelona, Spain.,Institut de Química Computacional i Catalisi and Departament de Química, Universitat de Girona, Girona, Spain
| | - Seung Seo Lee
- Department of Chemistry, University of Oxford, Oxford, UK.,School of Chemistry, University of Southampton, Southampton, UK
| | | | - Carme Rovira
- Departament de Química Inorgànica i Orgànica (Secció de Química Orgànica) and Institut de Química Teòrica i Computacional (IQTC), Universitat de Barcelona, Barcelona, Spain.,Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain
| | - Wyatt W Yue
- Structural Genomics Consortium, University of Oxford, Oxford, UK.
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3
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Bezborodkina NN, Chestnova AY, Vorobev ML, Kudryavtsev BN. Spatial Structure of Glycogen Molecules in Cells. BIOCHEMISTRY (MOSCOW) 2018; 83:467-482. [PMID: 29738682 DOI: 10.1134/s0006297918050012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Glycogen is a strongly branched polymer of α-D-glucose, with glucose residues in the linear chains linked by 1→4-bonds (~93% of the total number of bonds) and with branching after every 4-8 residues formed by 1→6-glycosidic bonds (~7% of the total number of bonds). It is thought currently that a fully formed glycogen molecule (β-particle) with the self-glycosylating protein glycogenin in the center has a spherical shape with diameter of ~42 nm and contains ~ 55,000 glucose residues. The glycogen molecule also includes numerous proteins involved in its synthesis and degradation, as well as proteins performing a carcass function. However, the type and force of bonds connecting these proteins to the polysaccharide moiety of glycogen are significantly different. This review presents the available data on the spatial structure of the glycogen molecule and its changes under various physiological and pathological conditions.
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Affiliation(s)
- N N Bezborodkina
- Institute of Cytology, Russian Academy of Sciences, St. Petersburg, 194064, Russia.
| | - A Yu Chestnova
- Institute of Cytology, Russian Academy of Sciences, St. Petersburg, 194064, Russia
| | - M L Vorobev
- Institute of Cytology, Russian Academy of Sciences, St. Petersburg, 194064, Russia
| | - B N Kudryavtsev
- Institute of Cytology, Russian Academy of Sciences, St. Petersburg, 194064, Russia
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4
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Tan X, Sullivan MA, Nada SS, Deng B, Schulz BL, Gilbert RG. Proteomic Investigation of the Binding Agent between Liver Glycogen β Particles. ACS OMEGA 2018; 3:3640-3645. [PMID: 30023874 PMCID: PMC6045358 DOI: 10.1021/acsomega.8b00119] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/20/2018] [Accepted: 03/22/2018] [Indexed: 06/08/2023]
Abstract
Glycogen is a highly branched glucose polymer which plays an important role in glucose storage and the maintenance of blood sugar homeostasis. The dimeric protein glycogenin can self-glucosylate to act as a primer for glycogen synthesis, eventually resulting in small (∼20 nm diameter) glycogen β particles with a dimer of glycogenin at their core. In the liver, glycogen is also found in the form of α particles: large bound composites of many β particles. Here, we provide evidence using qualitative and quantitative proteomics and size-exclusion chromatography from healthy rat, mouse, and human liver glycogen that glycogenin is the binding agent linking β particles together into α particles.
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Affiliation(s)
- Xinle Tan
- Joint
International Research Laboratory of Agriculture and Agri-Product
Safety, College of Agriculture, Yangzhou
University, Yangzhou 225009, Jiangsu Province, China
- School of Chemistry and Molecular
Biosciences and Centre for Nutrition and Food Sciences,
Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, Brisbane, Queensland 4072, Australia
- Tongji
School of Pharmacy and Department of Pharmacy, Union Hospital, Tongji Medical
College, Huazhong University of Science
and Technology, Wuhan, Hubei 430030, China
| | - Mitchell A. Sullivan
- Glycation
and Diabetes, Mater Research Institute, Translational Research Institute, The University of Queensland, Brisbane, Queensland 4102, Australia
| | - Sharif S. Nada
- School of Chemistry and Molecular
Biosciences and Centre for Nutrition and Food Sciences,
Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Bin Deng
- Tongji
School of Pharmacy and Department of Pharmacy, Union Hospital, Tongji Medical
College, Huazhong University of Science
and Technology, Wuhan, Hubei 430030, China
| | - Benjamin L. Schulz
- School of Chemistry and Molecular
Biosciences and Centre for Nutrition and Food Sciences,
Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Robert G. Gilbert
- Joint
International Research Laboratory of Agriculture and Agri-Product
Safety, College of Agriculture, Yangzhou
University, Yangzhou 225009, Jiangsu Province, China
- School of Chemistry and Molecular
Biosciences and Centre for Nutrition and Food Sciences,
Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, Brisbane, Queensland 4072, Australia
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5
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Abstract
Glycogen, the primary storage form of glucose, is a rapid and accessible form of energy that can be supplied to tissues on demand. Each glycogen granule, or "glycosome," is considered an independent metabolic unit composed of a highly branched polysaccharide and various proteins involved in its metabolism. In this Minireview, we review the literature to follow the dynamic life of a glycogen granule in a multicompartmentalized system, i.e. the cell, and how and where glycogen granules appear and the factors governing its degradation. A better understanding of the importance of cellular compartmentalization as a regulator of glycogen metabolism is needed to unravel its role in brain energetics.
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Affiliation(s)
- Clara Prats
- Center for Healthy Aging, Copenhagen 2200, Denmark; Core Facility for Integrated Microscopy, Department of Biomedical Sciences, University of Copenhagen, Copenhagen 2200, Denmark.
| | - Terry E Graham
- Department of Human Health and Nutritional Science, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Jane Shearer
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, Calgary, Alberta T2N 1N4, Canada; Faculty of Kinesiology, University of Calgary, Calgary, Alberta T2N 1N4, Canada
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6
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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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7
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Abstract
Glycogen is a branched polymer of glucose that acts as a store of energy in times of nutritional sufficiency for utilization in times of need. Its metabolism has been the subject of extensive investigation and much is known about its regulation by hormones such as insulin, glucagon and adrenaline (epinephrine). There has been debate over the relative importance of allosteric compared with covalent control of the key biosynthetic enzyme, glycogen synthase, as well as the relative importance of glucose entry into cells compared with glycogen synthase regulation in determining glycogen accumulation. Significant new developments in eukaryotic glycogen metabolism over the last decade or so include: (i) three-dimensional structures of the biosynthetic enzymes glycogenin and glycogen synthase, with associated implications for mechanism and control; (ii) analyses of several genetically engineered mice with altered glycogen metabolism that shed light on the mechanism of control; (iii) greater appreciation of the spatial aspects of glycogen metabolism, including more focus on the lysosomal degradation of glycogen; and (iv) glycogen phosphorylation and advances in the study of Lafora disease, which is emerging as a glycogen storage disease.
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Conformational plasticity of glycogenin and its maltosaccharide substrate during glycogen biogenesis. Proc Natl Acad Sci U S A 2011; 108:21028-33. [PMID: 22160680 DOI: 10.1073/pnas.1113921108] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Glycogenin initiates the synthesis of a maltosaccharide chain covalently attached to itself on Tyr195 via a stepwise glucosylation reaction, priming glycogen synthesis. We have captured crystallographic snapshots of human glycogenin during its reaction cycle, revealing a dynamic conformational switch between ground and active states mediated by the sugar donor UDP-glucose. This switch includes the ordering of a polypeptide stretch containing Tyr195, and major movement of an approximately 30-residue "lid" segment covering the active site. The rearranged lid guides the nascent maltosaccharide chain into the active site in either an intra- or intersubunit mode dependent upon chain length and steric factors and positions the donor and acceptor sugar groups for catalysis. The Thr83Met mutation, which causes glycogen storage disease XV, is conformationally locked in the ground state and catalytically inactive. Our data highlight the conformational plasticity of glycogenin and coexistence of two modes of glucosylation as integral to its catalytic mechanism.
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9
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Nilsson J, Halim A, Moslemi AR, Pedersen A, Nilsson J, Larson G, Oldfors A. Molecular pathogenesis of a new glycogenosis caused by a glycogenin-1 mutation. Biochim Biophys Acta Mol Basis Dis 2011; 1822:493-9. [PMID: 22198226 DOI: 10.1016/j.bbadis.2011.11.017] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2011] [Revised: 11/07/2011] [Accepted: 11/28/2011] [Indexed: 11/29/2022]
Abstract
Glycogenin-1 initiates the glycogen synthesis in skeletal muscle by the autocatalytic formation of a short oligosaccharide at tyrosine 195. Glycogenin-1 catalyzes both the glucose-O-tyrosine linkage and the α1,4 glucosidic bonds linking the glucose molecules in the oligosaccharide. We recently described a patient with glycogen depletion in skeletal muscle as a result of a non-functional glycogenin-1. The patient carried a Thr83Met substitution in glycogenin-1. In this study we have investigated the importance of threonine 83 for the catalytic activity of glycogenin-1. Non-glucosylated glycogenin-1 constructs, with various amino acid substitutions in position 83 and 195, were expressed in a cell-free expression system and autoglucosylated in vitro. The autoglucosylation was analyzed by gel-shift on western blot, incorporation of radiolabeled UDP-(14)C-glucose and nano-liquid chromatography with tandem mass spectrometry (LC/MS/MS). We demonstrate that glycogenin-1 with the Thr83Met substitution is unable to form the glucose-O-tyrosine linkage at tyrosine 195 unless co-expressed with the catalytically active Tyr195Phe glycogenin-1. Our results explain the glycogen depletion in the patient expressing only Thr83Met glycogenin-1 and why heterozygous carriers without clinical symptoms show a small proportion of unglucosylated glycogenin-1.
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Affiliation(s)
- Johanna Nilsson
- Department of Pathology, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden.
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10
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Issoglio FM, Carrizo ME, Romero JM, Curtino JA. Mechanisms of monomeric and dimeric glycogenin autoglucosylation. J Biol Chem 2011; 287:1955-61. [PMID: 22128147 DOI: 10.1074/jbc.m111.287813] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Initiation of glucose polymerization by glycogenin autoglucosylation at Tyr-194 is required to prime de novo biosynthesis of glycogen. It has been proposed that the synthesis of the primer proceeds by intersubunit glucosylation of dimeric glycogenin, even though it has not been demonstrated that this mechanism is responsible for the described polymerization extent of 12 glucoses produced by the dimer. We reported previously the intramonomer glucosylation capability of glycogenin without determining the extent of autoglucopolymerization. Here, we show that the maximum specific autoglucosylation extent (MSAE) produced by the non-glucosylated glycogenin monomer is 13.3 ± 1.9 glucose units, similar to the 12.5 ± 1.4 glucose units measured for the dimer. The mechanism and capacity of the dimeric enzyme to carry out full glucopolymerization were also evaluated by construction of heterodimers able to glucosylate exclusively by intrasubunit or intersubunit reaction mechanisms. The MSAE of non-glucosylated glycogenin produced by dimer intrasubunit glucosylation was 16% of that produced by the monomer. However, partially glucosylated glycogenin was able to almost complete its autoglucosylation by the dimer intrasubunit mechanism. The MSAE produced by heterodimer intersubunit glucosylation was 60% of that produced by the wild-type dimer. We conclude that both intrasubunit and intersubunit reaction mechanisms are necessary for the dimeric enzyme to acquire maximum autoglucosylation. The full glucopolymerization capacity of monomeric glycogenin indicates that the enzyme is able to synthesize the glycogen primer without the need for prior dimerization.
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Affiliation(s)
- Federico M Issoglio
- Centro de Investigaciones en Química Biológica de Córdoba (CIQUIBIC, Universidad Nacional de Córdoba-Consejo Nacional de Investigaciones Científicas y Técnicas (UNC-CONICET)), Departamento de Química Biológica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, X5000HUA Córdoba, Argentina
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Moslemi AR, Lindberg C, Nilsson J, Tajsharghi H, Andersson B, Oldfors A. Glycogenin-1 deficiency and inactivated priming of glycogen synthesis. N Engl J Med 2010; 362:1203-10. [PMID: 20357282 DOI: 10.1056/nejmoa0900661] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Glycogen, which serves as a major energy reserve in cells, is a large, branched polymer of glucose molecules. We describe a patient who had muscle weakness, associated with the depletion of glycogen in skeletal muscle, and cardiac arrhythmia, associated with the accumulation of abnormal storage material in the heart. The skeletal muscle showed a marked predominance of slow-twitch, oxidative muscle fibers and mitochondrial proliferation. Western blotting showed the presence of unglucosylated glycogenin-1 in the muscle and heart. Sequencing of the glycogenin-1 gene, GYG1, revealed a nonsense mutation in one allele and a missense mutation, Thr83Met, in the other. The missense mutation resulted in inactivation of the autoglucosylation of glycogenin-1 that is necessary for the priming of glycogen synthesis in muscle.
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Affiliation(s)
- Ali-Reza Moslemi
- Department of Pathology, Institute of Biomedicine, University of Gothenburg, Gothenburg, Sweden
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12
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Bazán S, Issoglio FM, Carrizo ME, Curtino JA. The intramolecular autoglucosylation of monomeric glycogenin. Biochem Biophys Res Commun 2008; 371:328-32. [DOI: 10.1016/j.bbrc.2008.04.076] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2008] [Accepted: 04/16/2008] [Indexed: 11/28/2022]
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13
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Morris GA, Ang S, Hill SE, Lewis S, Schäfer B, Nobbmann U, Harding SE. Molar mass and solution conformation of branched α(1→4), α(1→6) Glucans. Part I: Glycogens in water. Carbohydr Polym 2008. [DOI: 10.1016/j.carbpol.2007.05.029] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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