1
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Asif M, Nocilla KA, Ngo L, Shah M, Smadi Y, Hafeez Z, Parnes M, Manson A, Glushka JN, Leach FE, Edison AS. Role of UDP-Glycosyltransferase ( ugt) Genes in Detoxification and Glycosylation of 1-Hydroxyphenazine (1-HP) in Caenorhabditis elegans. Chem Res Toxicol 2024; 37:590-599. [PMID: 38488606 PMCID: PMC11022241 DOI: 10.1021/acs.chemrestox.3c00410] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 02/26/2024] [Accepted: 02/27/2024] [Indexed: 04/16/2024]
Abstract
Caenorhabditis elegans is a useful model organism to study the xenobiotic detoxification pathways of various natural and synthetic toxins, but the mechanisms of phase II detoxification are understudied. 1-Hydroxyphenazine (1-HP), a toxin produced by the bacterium Pseudomonas aeruginosa, kills C. elegans. We previously showed that C. elegans detoxifies 1-HP by adding one, two, or three glucose molecules in N2 worms. Our current study evaluates the roles that some UDP-glycosyltransferase (ugt) genes play in 1-HP detoxification. We show that ugt-23 and ugt-49 knockout mutants are more sensitive to 1-HP than reference strains N2 or PD1074. Our data also show that ugt-23 knockout mutants produce reduced amounts of the trisaccharide sugars, while the ugt-49 knockout mutants produce reduced amounts of all 1-HP derivatives except for the glucopyranosyl product compared to the reference strains. We characterized the structure of the trisaccharide sugar phenazines made by C. elegans and showed that one of the sugar modifications contains an N-acetylglucosamine (GlcNAc) in place of glucose. This implies broad specificity regarding UGT function and the role of genes other than ogt-1 in adding GlcNAc, at least in small-molecule detoxification.
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Affiliation(s)
- Muhammad
Zaka Asif
- Department
of Biochemistry & Molecular Biology, University of Georgia, Athens, Georgia 30602, United States
- Complex
Carbohydrate Research Center, University
of Georgia, Athens, Georgia 30602, United States
| | - Kelsey A. Nocilla
- Complex
Carbohydrate Research Center, University
of Georgia, Athens, Georgia 30602, United States
| | - Li Ngo
- Complex
Carbohydrate Research Center, University
of Georgia, Athens, Georgia 30602, United States
| | - Man Shah
- Complex
Carbohydrate Research Center, University
of Georgia, Athens, Georgia 30602, United States
| | - Yosef Smadi
- Complex
Carbohydrate Research Center, University
of Georgia, Athens, Georgia 30602, United States
| | - Zaki Hafeez
- Complex
Carbohydrate Research Center, University
of Georgia, Athens, Georgia 30602, United States
| | - Michael Parnes
- Complex
Carbohydrate Research Center, University
of Georgia, Athens, Georgia 30602, United States
| | - Allie Manson
- Complex
Carbohydrate Research Center, University
of Georgia, Athens, Georgia 30602, United States
| | - John N. Glushka
- Complex
Carbohydrate Research Center, University
of Georgia, Athens, Georgia 30602, United States
| | - Franklin E. Leach
- Complex
Carbohydrate Research Center, University
of Georgia, Athens, Georgia 30602, United States
- Department
of Chemistry, University of Georgia, Athens, Georgia 30602, United States
| | - Arthur S. Edison
- Department
of Biochemistry & Molecular Biology, University of Georgia, Athens, Georgia 30602, United States
- Complex
Carbohydrate Research Center, University
of Georgia, Athens, Georgia 30602, United States
- Institute
of Bioinformatics, University of Georgia, Athens, Georgia 30602, United States
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2
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Wang Y, Tran PM, Lahm ME, Xie Y, Wei P, Adams ER, Glushka JN, Ren Z, Popik VV, Schaefer HF, Robinson GH. Activation of Ammonia by a Carbene-Stabilized Dithiolene Zwitterion. J Am Chem Soc 2022; 144:16325-16331. [PMID: 36037279 DOI: 10.1021/jacs.2c07920] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
A carbene-stabilized dithiolene zwitterion (3) activates ammonia, affording 4• and 5, through both single-electron transfer (SET) and hydrogen atom transfer (HAT). Reaction products were characterized spectroscopically and by single-crystal X-ray diffraction. The mechanism of the formation of 4• and 5 was probed by experimental and computational methods. This discovery is the first example of metal-free ammonia activation via HAT.
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Affiliation(s)
- Yuzhong Wang
- Department of Chemistry, Center for Computational Chemistry, and Complex Carbohydrate Research Center, The University of Georgia, Athens, Georgia 30602-2556, United States
| | - Phuong M Tran
- Department of Chemistry, Center for Computational Chemistry, and Complex Carbohydrate Research Center, The University of Georgia, Athens, Georgia 30602-2556, United States
| | - Mitchell E Lahm
- Department of Chemistry, Center for Computational Chemistry, and Complex Carbohydrate Research Center, The University of Georgia, Athens, Georgia 30602-2556, United States
| | - Yaoming Xie
- Department of Chemistry, Center for Computational Chemistry, and Complex Carbohydrate Research Center, The University of Georgia, Athens, Georgia 30602-2556, United States
| | - Pingrong Wei
- Department of Chemistry, Center for Computational Chemistry, and Complex Carbohydrate Research Center, The University of Georgia, Athens, Georgia 30602-2556, United States
| | - Earle R Adams
- Department of Chemistry, Center for Computational Chemistry, and Complex Carbohydrate Research Center, The University of Georgia, Athens, Georgia 30602-2556, United States
| | - John N Glushka
- Department of Chemistry, Center for Computational Chemistry, and Complex Carbohydrate Research Center, The University of Georgia, Athens, Georgia 30602-2556, United States
| | - Zichun Ren
- Department of Chemistry, Center for Computational Chemistry, and Complex Carbohydrate Research Center, The University of Georgia, Athens, Georgia 30602-2556, United States
| | - Vladimir V Popik
- Department of Chemistry, Center for Computational Chemistry, and Complex Carbohydrate Research Center, The University of Georgia, Athens, Georgia 30602-2556, United States
| | - Henry F Schaefer
- Department of Chemistry, Center for Computational Chemistry, and Complex Carbohydrate Research Center, The University of Georgia, Athens, Georgia 30602-2556, United States
| | - Gregory H Robinson
- Department of Chemistry, Center for Computational Chemistry, and Complex Carbohydrate Research Center, The University of Georgia, Athens, Georgia 30602-2556, United States
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3
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Wang Y, Tran PM, Xie Y, Wei P, Glushka JN, Schaefer HF, Robinson GH. Carbene‐Stabilized Dithiolene (L
0
) Zwitterions. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202108498] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Yuzhong Wang
- Department of Chemistry, Center for Computational Chemistry, and Complex Carbohydrate Research Center The University of Georgia Athens GA 30602-2556 USA
| | - Phuong M. Tran
- Department of Chemistry, Center for Computational Chemistry, and Complex Carbohydrate Research Center The University of Georgia Athens GA 30602-2556 USA
| | - Yaoming Xie
- Department of Chemistry, Center for Computational Chemistry, and Complex Carbohydrate Research Center The University of Georgia Athens GA 30602-2556 USA
| | - Pingrong Wei
- Department of Chemistry, Center for Computational Chemistry, and Complex Carbohydrate Research Center The University of Georgia Athens GA 30602-2556 USA
| | - John N. Glushka
- Department of Chemistry, Center for Computational Chemistry, and Complex Carbohydrate Research Center The University of Georgia Athens GA 30602-2556 USA
| | - Henry F. Schaefer
- Department of Chemistry, Center for Computational Chemistry, and Complex Carbohydrate Research Center The University of Georgia Athens GA 30602-2556 USA
| | - Gregory H. Robinson
- Department of Chemistry, Center for Computational Chemistry, and Complex Carbohydrate Research Center The University of Georgia Athens GA 30602-2556 USA
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4
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Wang Y, Tran PM, Xie Y, Wei P, Glushka JN, Schaefer HF, Robinson GH. Carbene-Stabilized Dithiolene (L 0 ) Zwitterions. Angew Chem Int Ed Engl 2021; 60:22706-22710. [PMID: 34314562 DOI: 10.1002/anie.202108498] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 07/23/2021] [Indexed: 11/06/2022]
Abstract
A series of reactions between Lewis bases and an imidazole-based dithione dimer (1) has been investigated. Both cyclic(alkyl)(amino)carbene (CAAC) (2) and N-heterocyclic carbene (NHC) (4), in addition to N-heterocyclic silylene (NHSi) (6), demonstrate the capability to cleave the sulphur-sulphur bonds in 1, giving carbene-stabilized dithiolene (L0 ) zwitterions (3 and 5) and a spirocyclic silicon-dithiolene compound (7), respectively. The bonding nature of 3, 5, and 7 are probed by both experimental and theoretical methods.
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Affiliation(s)
- Yuzhong Wang
- Department of Chemistry, Center for Computational Chemistry, and Complex Carbohydrate Research Center, The University of Georgia, Athens, GA, 30602-2556, USA
| | - Phuong M Tran
- Department of Chemistry, Center for Computational Chemistry, and Complex Carbohydrate Research Center, The University of Georgia, Athens, GA, 30602-2556, USA
| | - Yaoming Xie
- Department of Chemistry, Center for Computational Chemistry, and Complex Carbohydrate Research Center, The University of Georgia, Athens, GA, 30602-2556, USA
| | - Pingrong Wei
- Department of Chemistry, Center for Computational Chemistry, and Complex Carbohydrate Research Center, The University of Georgia, Athens, GA, 30602-2556, USA
| | - John N Glushka
- Department of Chemistry, Center for Computational Chemistry, and Complex Carbohydrate Research Center, The University of Georgia, Athens, GA, 30602-2556, USA
| | - Henry F Schaefer
- Department of Chemistry, Center for Computational Chemistry, and Complex Carbohydrate Research Center, The University of Georgia, Athens, GA, 30602-2556, USA
| | - Gregory H Robinson
- Department of Chemistry, Center for Computational Chemistry, and Complex Carbohydrate Research Center, The University of Georgia, Athens, GA, 30602-2556, USA
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5
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Kuprov I, Morris LC, Glushka JN, Prestegard JH. Using molecular dynamics trajectories to predict nuclear spin relaxation behaviour in large spin systems. J Magn Reson 2021; 323:106891. [PMID: 33445107 PMCID: PMC7873838 DOI: 10.1016/j.jmr.2020.106891] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 12/07/2020] [Accepted: 12/08/2020] [Indexed: 05/09/2023]
Abstract
Molecular dynamics (MD) trajectories provide useful insights into molecular structure and dynamics. However, questions persist about the quantitative accuracy of those insights. Experimental NMR spin relaxation rates can be used as tests, but only if relaxation superoperators can be efficiently computed from MD trajectories - no mean feat for the quantum Liouville space formalism where matrix dimensions quadruple with each added spin 1/2. Here we report a module for the Spinach software framework that computes Bloch-Redfield-Wangsness relaxation superoperators (including non-secular terms and cross-correlations) from MD trajectories. Predicted initial slopes of nuclear Overhauser effects for sucrose trajectories using advanced water models and a force field optimised for glycans are within 25% of experimental values.
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Affiliation(s)
- Ilya Kuprov
- School of Chemistry, University of Southampton, Southampton, UK
| | - Laura C Morris
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, United States
| | - John N Glushka
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, United States
| | - James H Prestegard
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, United States.
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6
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Mandalasi M, Kim HW, Thieker D, Sheikh MO, Gas-Pascual E, Rahman K, Zhao P, Daniel NG, van der Wel H, Ichikawa HT, Glushka JN, Wells L, Woods RJ, Wood ZA, West CM. A terminal α3-galactose modification regulates an E3 ubiquitin ligase subunit in Toxoplasma gondii. J Biol Chem 2020; 295:9223-9243. [PMID: 32414843 PMCID: PMC7335778 DOI: 10.1074/jbc.ra120.013792] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2020] [Revised: 05/14/2020] [Indexed: 12/29/2022] Open
Abstract
Skp1, a subunit of E3 Skp1/Cullin-1/F-box protein ubiquitin ligases, is modified by a prolyl hydroxylase that mediates O2 regulation of the social amoeba Dictyostelium and the parasite Toxoplasma gondii The full effect of hydroxylation requires modification of the hydroxyproline by a pentasaccharide that, in Dictyostelium, influences Skp1 structure to favor assembly of Skp1/F-box protein subcomplexes. In Toxoplasma, the presence of a contrasting penultimate sugar assembled by a different glycosyltransferase enables testing of the conformational control model. To define the final sugar and its linkage, here we identified the glycosyltransferase that completes the glycan and found that it is closely related to glycogenin, an enzyme that may prime glycogen synthesis in yeast and animals. However, the Toxoplasma enzyme catalyzes formation of a Galα1,3Glcα linkage rather than the Glcα1,4Glcα linkage formed by glycogenin. Kinetic and crystallographic experiments showed that the glycosyltransferase Gat1 is specific for Skp1 in Toxoplasma and also in another protist, the crop pathogen Pythium ultimum The fifth sugar is important for glycan function as indicated by the slow-growth phenotype of gat1Δ parasites. Computational analyses indicated that, despite the sequence difference, the Toxoplasma glycan still assumes an ordered conformation that controls Skp1 structure and revealed the importance of nonpolar packing interactions of the fifth sugar. The substitution of glycosyltransferases in Toxoplasma and Pythium by an unrelated bifunctional enzyme that assembles a distinct but structurally compatible glycan in Dictyostelium is a remarkable case of convergent evolution, which emphasizes the importance of the terminal α-galactose and establishes the phylogenetic breadth of Skp1 glycoregulation.
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Affiliation(s)
- Msano Mandalasi
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA; Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia, USA
| | - Hyun W Kim
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA
| | - David Thieker
- Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia, USA
| | - M Osman Sheikh
- Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia, USA
| | - Elisabet Gas-Pascual
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA; Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia, USA
| | - Kazi Rahman
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA
| | - Peng Zhao
- Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia, USA
| | - Nitin G Daniel
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA
| | - Hanke van der Wel
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA
| | - H Travis Ichikawa
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA
| | - John N Glushka
- Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia, USA
| | - Lance Wells
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA; Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia, USA
| | - Robert J Woods
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA; Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia, USA
| | - Zachary A Wood
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA
| | - Christopher M West
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA; Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, Georgia, USA; Complex Carbohydrate Research Center, University of Georgia, Athens, Georgia, USA.
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7
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Sheikh MO, Venzke D, Anderson ME, Yoshida-Moriguchi T, Glushka JN, Nairn AV, Galizzi M, Moremen KW, Campbell KP, Wells L. HNK-1 sulfotransferase modulates α-dystroglycan glycosylation by 3-O-sulfation of glucuronic acid on matriglycan. Glycobiology 2020; 30:817-829. [PMID: 32149355 DOI: 10.1093/glycob/cwaa024] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2019] [Revised: 02/26/2020] [Accepted: 02/26/2020] [Indexed: 12/18/2022] Open
Abstract
Mutations in multiple genes required for proper O-mannosylation of α-dystroglycan are causal for congenital/limb-girdle muscular dystrophies and abnormal brain development in mammals. Previously, we and others further elucidated the functional O-mannose glycan structure that is terminated by matriglycan, [(-GlcA-β3-Xyl-α3-)n]. This repeating disaccharide serves as a receptor for proteins in the extracellular matrix. Here, we demonstrate in vitro that HNK-1 sulfotransferase (HNK-1ST/carbohydrate sulfotransferase) sulfates terminal glucuronyl residues of matriglycan at the 3-hydroxyl and prevents further matriglycan polymerization by the LARGE1 glycosyltransferase. While α-dystroglycan isolated from mouse heart and kidney is susceptible to exoglycosidase digestion of matriglycan, the functional, lower molecular weight α-dystroglycan detected in brain, where HNK-1ST expression is elevated, is resistant. Removal of the sulfate cap by a sulfatase facilitated dual-glycosidase digestion. Our data strongly support a tissue specific mechanism in which HNK-1ST regulates polymer length by competing with LARGE for the 3-position on the nonreducing GlcA of matriglycan.
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Affiliation(s)
- M Osman Sheikh
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, USA
| | - David Venzke
- Department of Molecular Physiology and Biophysics, Department of Neurology, Howard Hughes Medical Institute, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, IA 52242, USA
| | - Mary E Anderson
- Department of Molecular Physiology and Biophysics, Department of Neurology, Howard Hughes Medical Institute, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, IA 52242, USA
| | - Takako Yoshida-Moriguchi
- Department of Molecular Physiology and Biophysics, Department of Neurology, Howard Hughes Medical Institute, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, IA 52242, USA
| | - John N Glushka
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, USA
| | - Alison V Nairn
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, USA
| | - Melina Galizzi
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, USA
| | - Kelley W Moremen
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, USA.,Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
| | - Kevin P Campbell
- Department of Molecular Physiology and Biophysics, Department of Neurology, Howard Hughes Medical Institute, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, IA 52242, USA
| | - Lance Wells
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, USA.,Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
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8
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Sheikh MO, Gas-Pascual E, Glushka JN, Bustamante JM, Wells L, West CM. Trypanosoma cruzi 13C-labeled O-Glycan standards for mass spectrometry. Glycobiology 2019; 29:280-284. [PMID: 30649355 DOI: 10.1093/glycob/cwy111] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Revised: 11/20/2018] [Accepted: 12/15/2018] [Indexed: 01/26/2023] Open
Abstract
Trypanosoma cruzi is a protozoan parasite that causes Chagas disease, a debilitating condition that affects over 10 million humans in the American continents. In addition to its traditional mode of human entry via the "kissing bug" in endemic areas, the infection can also be spread in non-endemic countries through blood transfusion, organ transplantation, eating food contaminated with the parasites, and from mother to fetus. Previous NMR-based studies established that the parasite expresses a variety of strain-specific and developmentally-regulated O-glycans that may contribute to virulence. In this report, we describe five synthetic O-glycan analytical standards and show their potential to enable a more facile analysis of native O-glycan isomers based on mass spectrometry.
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Affiliation(s)
- M Osman Sheikh
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, USA.,Complex Carbohydrate Research Center, University of Georgia, Athens, GA, USA
| | - Elisabet Gas-Pascual
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, USA.,Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA, USA
| | - John N Glushka
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA, USA
| | - Juan M Bustamante
- Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA, USA
| | - Lance Wells
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, USA.,Complex Carbohydrate Research Center, University of Georgia, Athens, GA, USA
| | - Christopher M West
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, USA.,Complex Carbohydrate Research Center, University of Georgia, Athens, GA, USA.,Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA, USA
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9
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Amon R, Grant OC, Leviatan Ben-Arye S, Makeneni S, Nivedha AK, Marshanski T, Norn C, Yu H, Glushka JN, Fleishman SJ, Chen X, Woods RJ, Padler-Karavani V. A combined computational-experimental approach to define the structural origin of antibody recognition of sialyl-Tn, a tumor-associated carbohydrate antigen. Sci Rep 2018; 8:10786. [PMID: 30018351 PMCID: PMC6050261 DOI: 10.1038/s41598-018-29209-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Accepted: 07/06/2018] [Indexed: 12/16/2022] Open
Abstract
Anti-carbohydrate monoclonal antibodies (mAbs) hold great promise as cancer therapeutics and diagnostics. However, their specificity can be mixed, and detailed characterization is problematic, because antibody-glycan complexes are challenging to crystallize. Here, we developed a generalizable approach employing high-throughput techniques for characterizing the structure and specificity of such mAbs, and applied it to the mAb TKH2 developed against the tumor-associated carbohydrate antigen sialyl-Tn (STn). The mAb specificity was defined by apparent KD values determined by quantitative glycan microarray screening. Key residues in the antibody combining site were identified by site-directed mutagenesis, and the glycan-antigen contact surface was defined using saturation transfer difference NMR (STD-NMR). These features were then employed as metrics for selecting the optimal 3D-model of the antibody-glycan complex, out of thousands plausible options generated by automated docking and molecular dynamics simulation. STn-specificity was further validated by computationally screening of the selected antibody 3D-model against the human sialyl-Tn-glycome. This computational-experimental approach would allow rational design of potent antibodies targeting carbohydrates.
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Affiliation(s)
- Ron Amon
- Department of Cell Research and Immunology, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, 69978, Israel
| | - Oliver C Grant
- Complex Carbohydrate Research Center, University of Georgia, Athens, 30606, GA, USA
| | - Shani Leviatan Ben-Arye
- Department of Cell Research and Immunology, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, 69978, Israel
| | - Spandana Makeneni
- Complex Carbohydrate Research Center, University of Georgia, Athens, 30606, GA, USA
| | - Anita K Nivedha
- Complex Carbohydrate Research Center, University of Georgia, Athens, 30606, GA, USA
| | - Tal Marshanski
- Department of Cell Research and Immunology, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, 69978, Israel
| | - Christoffer Norn
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Hai Yu
- Department of Chemistry, University of California-Davis, Davis, CA, USA
| | - John N Glushka
- Complex Carbohydrate Research Center, University of Georgia, Athens, 30606, GA, USA
| | - Sarel J Fleishman
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Xi Chen
- Department of Chemistry, University of California-Davis, Davis, CA, USA
| | - Robert J Woods
- Complex Carbohydrate Research Center, University of Georgia, Athens, 30606, GA, USA.
| | - Vered Padler-Karavani
- Department of Cell Research and Immunology, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, 69978, Israel.
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10
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Sheikh MO, Thieker D, Chalmers G, Schafer CM, Ishihara M, Azadi P, Woods RJ, Glushka JN, Bendiak B, Prestegard JH, West CM. O 2 sensing-associated glycosylation exposes the F-box-combining site of the Dictyostelium Skp1 subunit in E3 ubiquitin ligases. J Biol Chem 2017; 292:18897-18915. [PMID: 28928219 PMCID: PMC5704474 DOI: 10.1074/jbc.m117.809160] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 09/12/2017] [Indexed: 11/06/2022] Open
Abstract
Skp1 is a conserved protein linking cullin-1 to F-box proteins in SCF (Skp1/Cullin-1/F-box protein) E3 ubiquitin ligases, which modify protein substrates with polyubiquitin chains that typically target them for 26S proteasome-mediated degradation. In Dictyostelium (a social amoeba), Toxoplasma gondii (the agent for human toxoplasmosis), and other protists, Skp1 is regulated by a unique pentasaccharide attached to hydroxylated Pro-143 within its C-terminal F-box-binding domain. Prolyl hydroxylation of Skp1 contributes to O2-dependent Dictyostelium development, but full glycosylation at that position is required for optimal O2 sensing. Previous studies have shown that the glycan promotes organization of the F-box-binding region in Skp1 and aids in Skp1's association with F-box proteins. Here, NMR and MS approaches were used to determine the glycan structure, and then a combination of NMR and molecular dynamics simulations were employed to characterize the impact of the glycan on the conformation and motions of the intrinsically flexible F-box-binding domain of Skp1. Molecular dynamics trajectories of glycosylated Skp1 whose calculated monosaccharide relaxation kinetics and rotational correlation times agreed with the NMR data indicated that the glycan interacts with the loop connecting two α-helices of the F-box-combining site. In these trajectories, the helices separated from one another to create a more accessible and dynamic F-box interface. These results offer an unprecedented view of how a glycan modification influences a disordered region of a full-length protein. The increased sampling of an open Skp1 conformation can explain how glycosylation enhances interactions with F-box proteins in cells.
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Affiliation(s)
- M Osman Sheikh
- From the Department of Biochemistry and Molecular Biology
- the Complex Carbohydrate Research Center, and
- the Department of Biochemistry and Molecular Biology, Oklahoma Center for Medical Glycobiology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104, and
| | | | - Gordon Chalmers
- the Complex Carbohydrate Research Center, and
- the Department of Computer Science, University of Georgia, Athens, Georgia 30602
| | - Christopher M Schafer
- the Department of Biochemistry and Molecular Biology, Oklahoma Center for Medical Glycobiology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104, and
| | | | | | - Robert J Woods
- From the Department of Biochemistry and Molecular Biology
- the Complex Carbohydrate Research Center, and
| | | | - Brad Bendiak
- the Department of Cell and Developmental Biology, School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045
| | - James H Prestegard
- From the Department of Biochemistry and Molecular Biology
- the Complex Carbohydrate Research Center, and
| | - Christopher M West
- From the Department of Biochemistry and Molecular Biology,
- the Department of Biochemistry and Molecular Biology, Oklahoma Center for Medical Glycobiology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104, and
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11
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Cliff TS, Wu T, Boward BR, Yin A, Yin H, Glushka JN, Prestegaard JH, Dalton S. MYC Controls Human Pluripotent Stem Cell Fate Decisions through Regulation of Metabolic Flux. Cell Stem Cell 2017; 21:502-516.e9. [PMID: 28965765 DOI: 10.1016/j.stem.2017.08.018] [Citation(s) in RCA: 97] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Revised: 07/27/2017] [Accepted: 08/27/2017] [Indexed: 01/07/2023]
Abstract
As human pluripotent stem cells (hPSCs) exit pluripotency, they are thought to switch from a glycolytic mode of energy generation to one more dependent on oxidative phosphorylation. Here we show that, although metabolic switching occurs during early mesoderm and endoderm differentiation, high glycolytic flux is maintained and, in fact, essential during early ectoderm specification. The elevated glycolysis observed in hPSCs requires elevated MYC/MYCN activity. Metabolic switching during endodermal and mesodermal differentiation coincides with a reduction in MYC/MYCN and can be reversed by ectopically restoring MYC activity. During early ectodermal differentiation, sustained MYCN activity maintains the transcription of "switch" genes that are rate-limiting for metabolic activity and lineage commitment. Our work, therefore, shows that metabolic switching is lineage-specific and not a required step for exit of pluripotency in hPSCs and identifies MYC and MYCN as developmental regulators that couple metabolism to pluripotency and cell fate determination.
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Affiliation(s)
- Timothy S Cliff
- Department of Biochemistry and Molecular Biology, University of Georgia, 500 D.W. Brooks Drive, Athens, GA 30602, USA; Center for Molecular Medicine, University of Georgia, 500 D.W. Brooks Drive, Athens, GA 30602, USA
| | - Tianming Wu
- Department of Biochemistry and Molecular Biology, University of Georgia, 500 D.W. Brooks Drive, Athens, GA 30602, USA; Center for Molecular Medicine, University of Georgia, 500 D.W. Brooks Drive, Athens, GA 30602, USA
| | - Benjamin R Boward
- Department of Biochemistry and Molecular Biology, University of Georgia, 500 D.W. Brooks Drive, Athens, GA 30602, USA; Center for Molecular Medicine, University of Georgia, 500 D.W. Brooks Drive, Athens, GA 30602, USA
| | - Amelia Yin
- Department of Biochemistry and Molecular Biology, University of Georgia, 500 D.W. Brooks Drive, Athens, GA 30602, USA; Center for Molecular Medicine, University of Georgia, 500 D.W. Brooks Drive, Athens, GA 30602, USA
| | - Hang Yin
- Department of Biochemistry and Molecular Biology, University of Georgia, 500 D.W. Brooks Drive, Athens, GA 30602, USA; Center for Molecular Medicine, University of Georgia, 500 D.W. Brooks Drive, Athens, GA 30602, USA
| | - John N Glushka
- Department of Biochemistry and Molecular Biology, University of Georgia, 500 D.W. Brooks Drive, Athens, GA 30602, USA; Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Road, Athens, GA 30602, USA
| | - James H Prestegaard
- Department of Biochemistry and Molecular Biology, University of Georgia, 500 D.W. Brooks Drive, Athens, GA 30602, USA; Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Road, Athens, GA 30602, USA
| | - Stephen Dalton
- Department of Biochemistry and Molecular Biology, University of Georgia, 500 D.W. Brooks Drive, Athens, GA 30602, USA; Center for Molecular Medicine, University of Georgia, 500 D.W. Brooks Drive, Athens, GA 30602, USA.
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12
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Rahman K, Mandalasi M, Zhao P, Sheikh MO, Taujale R, Kim HW, van der Wel H, Matta K, Kannan N, Glushka JN, Wells L, West CM. Characterization of a cytoplasmic glucosyltransferase that extends the core trisaccharide of the Toxoplasma Skp1 E3 ubiquitin ligase subunit. J Biol Chem 2017; 292:18644-18659. [PMID: 28928220 DOI: 10.1074/jbc.m117.809301] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Revised: 09/12/2017] [Indexed: 01/06/2023] Open
Abstract
Skp1 is a subunit of the SCF (Skp1/Cullin 1/F-box protein) class of E3 ubiquitin ligases that are important for eukaryotic protein degradation. Unlike its animal counterparts, Skp1 from Toxoplasma gondii is hydroxylated by an O2-dependent prolyl-4-hydroxylase (PhyA), and the resulting hydroxyproline can subsequently be modified by a five-sugar chain. A similar modification is found in the social amoeba Dictyostelium, where it regulates SCF assembly and O2-dependent development. Homologous glycosyltransferases assemble a similar core trisaccharide in both organisms, and a bifunctional α-galactosyltransferase from CAZy family GT77 mediates the addition of the final two sugars in Dictyostelium, generating Galα1, 3Galα1,3Fucα1,2Galβ1,3GlcNAcα1-. Here, we found that Toxoplasma utilizes a cytoplasmic glycosyltransferase from an ancient clade of CAZy family GT32 to catalyze transfer of the fourth sugar. Catalytically active Glt1 was required for the addition of the terminal disaccharide in cells, and cytosolic extracts catalyzed transfer of [3H]glucose from UDP-[3H]glucose to the trisaccharide form of Skp1 in a glt1-dependent fashion. Recombinant Glt1 catalyzed the same reaction, confirming that it directly mediates Skp1 glucosylation, and NMR demonstrated formation of a Glcα1,3Fuc linkage. Recombinant Glt1 strongly preferred the full core trisaccharide attached to Skp1 and labeled only Skp1 in glt1Δ extracts, suggesting specificity for Skp1. glt1-knock-out parasites exhibited a growth defect not rescued by catalytically inactive Glt1, indicating that the glycan acts in concert with the first enzyme in the pathway, PhyA, in cells. A genomic bioinformatics survey suggested that Glt1 belongs to the ancestral Skp1 glycosylation pathway in protists and evolved separately from related Golgi-resident GT32 glycosyltransferases.
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Affiliation(s)
- Kazi Rahman
- From the Department of Biochemistry and Molecular Biology.,the Departments of Microbiology and Immunology and
| | - Msano Mandalasi
- From the Department of Biochemistry and Molecular Biology.,Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104, and
| | - Peng Zhao
- the Complex Carbohydrate Research Center, and
| | | | - Rahil Taujale
- the Complex Carbohydrate Research Center, and.,the Institute of Bioinformatics, University of Georgia, Athens, Georgia 30602
| | - Hyun W Kim
- From the Department of Biochemistry and Molecular Biology
| | | | - Khushi Matta
- the Department of Chemical and Biological Engineering, State University of New York, Buffalo, New York 14260
| | - Natarajan Kannan
- From the Department of Biochemistry and Molecular Biology.,the Institute of Bioinformatics, University of Georgia, Athens, Georgia 30602
| | | | - Lance Wells
- From the Department of Biochemistry and Molecular Biology.,the Complex Carbohydrate Research Center, and
| | - Christopher M West
- From the Department of Biochemistry and Molecular Biology, .,Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104, and
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13
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Chalmers G, Glushka JN, Foley BL, Woods RJ, Prestegard JH. Direct NOE simulation from long MD trajectories. J Magn Reson 2016; 265:1-9. [PMID: 26826977 PMCID: PMC4818662 DOI: 10.1016/j.jmr.2016.01.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Revised: 01/10/2016] [Accepted: 01/12/2016] [Indexed: 05/08/2023]
Abstract
A software package, MD2NOE, is presented which calculates Nuclear Overhauser Effect (NOE) build-up curves directly from molecular dynamics (MD) trajectories. It differs from traditional approaches in that it calculates correlation functions directly from the trajectory instead of extracting inverse sixth power distance terms as an intermediate step in calculating NOEs. This is particularly important for molecules that sample conformational states on a timescale similar to molecular reorientation. The package is tested on sucrose and results are shown to differ in small but significant ways from those calculated using an inverse sixth power assumption. Results are also compared to experiment and found to be in reasonable agreement despite an expected underestimation of water viscosity by the water model selected.
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Affiliation(s)
- G Chalmers
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, United States
| | - J N Glushka
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, United States
| | - B L Foley
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, United States
| | - R J Woods
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, United States
| | - J H Prestegard
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, United States.
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14
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Abstract
The growing importance of biologics and biosimilars as therapeutic and diagnostic agents is giving rise to new demands for analytical methodology that can quickly and accurately assess the chemical and physical state of protein-based products. A particular challenge exists in physical characterization where the proper fold and extent of disorder of a protein is a major concern. The ability of NMR to reflect structural and dynamic properties of proteins is well recognized, but sensitivity limitations and high levels of interference from excipients in typical biologic formulations have prevented widespread applications to quality assessment. Here we demonstrate applicability of a simple one-dimensional proton NMR method that exploits enhanced spin diffusion among protons in well-structured areas of a protein. We show that it is possible to reduce excipient signals and allow focus on structural characteristics of the protein. Additional decomposition of the resulting spectra based on rotating frame spin relaxation allows separate examination of components from aggregates and disordered regions. Application to a comparison of two different monoclonal antibodies and to detection of partial pH denaturation of a monoclonal antibody illustrates the procedure.
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Affiliation(s)
- Joshua Franks
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602
| | - John N. Glushka
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602
| | - Michael T. Jones
- Analytical Research and Development, Biotherapeutics Pharmaceutical Sciences, Pfizer Inc, St. Louis MO
| | - David H. Live
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602
| | - Qin Zou
- Analytical Research and Development, Biotherapeutics Pharmaceutical Sciences, Pfizer Inc, St. Louis MO
| | - James H. Prestegard
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602
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15
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Queiroz INL, Wang X, Glushka JN, Santos GRC, Valente AP, Prestegard JH, Woods RJ, Mourão PAS, Pomin VH. Impact of sulfation pattern on the conformation and dynamics of sulfated fucan oligosaccharides as revealed by NMR and MD. Glycobiology 2014; 25:535-47. [PMID: 25527427 DOI: 10.1093/glycob/cwu184] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Sulfated fucans from sea urchin egg jelly express well-defined chemical structures that vary with species. This species specificity regulates the sperm acrosome reaction, a critical step to assure intra-specific fertilization. In addition, these polysaccharides are involved in other biological activities such as anticoagulation. Although sulfation patterns are relevant to the levels of response in both activities, conformation and dynamics of these glycans are also contributing factors. However, data about these features of sulfated fucans are very rare. To address this, we have employed nuclear magnetic resonance experiments combined with molecular dynamics on structurally defined oligosaccharides derived from two sulfated fucans. The results have indicated that the oligosaccharides are flexible in solution. Ring conformation of their composing units displays just the (1)C4 chair configuration. In a particular octasaccharide, composed of two tetrasaccharide sequences, inter-residual hydrogen bonds play a role to decrease dynamics in these repeating units. Conversely, the linking disaccharide [-3)-α-L-Fucp-2(OSO3(-))-(1-3)-α-L-Fucp-4(OCO3(-))-(1-] located right between the two tetrasaccharide units has amplified motions suggested to be promoted by electrostatic repulsion of sulfates on opposite sides of the central glycosidic bond. This conjunction of information about conformation and dynamics of sulfated fucan oligosaccharides provides new insights to explain how these glycans behave free in solution and influenced by sulfation patterns. It may also serve for future studies concerning structure-function relationship of sulfated fucans, especially those involving sea urchin fertilization and anticoagulation.
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Affiliation(s)
- Ismael N L Queiroz
- Programa de Glicobiologia, Instituto de Bioquímica Médica Leopoldo de Meis, and Hospital Universitário Clementino Fraga Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ 21941-913, Brazil
| | - Xiaocong Wang
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, USA
| | - John N Glushka
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, USA
| | - Gustavo R C Santos
- Programa de Glicobiologia, Instituto de Bioquímica Médica Leopoldo de Meis, and Hospital Universitário Clementino Fraga Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ 21941-913, Brazil
| | - Ana P Valente
- Centro Nacional de Ressonância Nuclear Magnética de Macromoléculas, Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ 21941-902, Brasil
| | - James H Prestegard
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, USA
| | - Robert J Woods
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, USA
| | - Paulo A S Mourão
- Programa de Glicobiologia, Instituto de Bioquímica Médica Leopoldo de Meis, and Hospital Universitário Clementino Fraga Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ 21941-913, Brazil
| | - Vitor H Pomin
- Programa de Glicobiologia, Instituto de Bioquímica Médica Leopoldo de Meis, and Hospital Universitário Clementino Fraga Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ 21941-913, Brazil
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16
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Abstract
The surfaces of mammalian cells are coated with complex carbohydrates, many terminated with a negatively charged N-acetylneuraminic acid residue. This motif is specifically targeted by pathogens, including influenza viruses and many pathogenic bacteria, to gain entry into the cell. A necessary step in the influenza virus life cycle is the release of viral particles from the cell surface; this is achieved by cleaving N-acetylneuraminic acid from cell surface glycans with a virally-produced neuraminidase. Here we present a laboratory exercise to model this process using a glycoprotein as a glycan carrier and using real time nuclear magnetic resonance (NMR) spectroscopy to monitor N-acetylneuraminic acid release as catalyzed by neuraminidase. A time-resolved two dimensional data processing technique, statistical total correlation spectroscopy (STOCSY), enhances the resolution of the complicated 1D glycoprotein spectrum and isolates characteristic peaks corresponding to substrates and products. This exercise is relatively straightforward and leads students through a wide range of biologically and chemically relevant procedures, including use of NMR spectroscopy, enzymology and data processing techniques.
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17
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Glushka JN, Terrell M, York WS, O'Neill MA, Gucwa A, Darvill AG, Albersheim P, Prestegard JH. Primary structure of the 2-O-methyl-alpha-L-fucose-containing side chain of the pectic polysaccharide, rhamnogalacturonan II. Carbohydr Res 2003; 338:341-52. [PMID: 12559732 DOI: 10.1016/s0008-6215(02)00461-5] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
A 2-O-methylfucosyl-containing heptasaccharide was released from red wine rhamnogalacturonan II (RG-II) by acid hydrolysis of the glycosidic linkage of the aceryl acid residue (AceA) and purified to homogeneity by size-exclusion and high-performance anion-exchange chromatographies. The primary structure of the heptasaccharide was determined by glycosyl-residue and glycosyl-linkage composition analyses, ESIMS, and by 1H and 13C NMR spectroscopy. The NMR data indicated that the pyranose ring of the 2,3-linked L-arabinosyl residue is conformationally flexible. The L-Arap residue was confirmed to be alpha-linked by NMR analysis of a tetraglycosyl-glycerol fragment, [alpha-L-Arap-(1-->4)-beta-D-Galp-(1-->2)-alpha-L-AcefA-(1-->3)-beta-L-Rhap-(1-->3)-Gro], generated by Smith degradation of RG-II. Our data together with the results of a previous study,(1) establish that the 2-O-Me Fuc-containing nonasaccharide side chain of wine RG-II has the structure (Api [triple bond] apiose): [see structure]. Data are presented to show that in Arabidopsis RG-II the predominant 2-O-MeFuc-containing side chain is a mono-O-acetylated heptasaccharide that lacks the non-reducing terminal beta-L-Araf and the alpha-L-Rhap residue attached to the O-3 of Arap, both of which are present on the wine nonasaccharide.
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Affiliation(s)
- John N Glushka
- Complex Carbohydrate Research Center, Department of Chemistry, The University of Georgia, 220 Riverbend Road, Athens, GA 30602-4712, USA
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18
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Yang YL, Glushka JN, Whitman WB. Intracellular pyruvate flux in the methane-producing archaeon Methanococcus maripaludis. Arch Microbiol 2002; 178:493-8. [PMID: 12420171 DOI: 10.1007/s00203-002-0480-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2002] [Revised: 08/16/2002] [Accepted: 08/19/2002] [Indexed: 11/29/2022]
Abstract
During growth of the methanogenic archaeon Methanococcus maripaludis on alanine as the sole nitrogen source under H(2)/CO(2), alanine was incorporated into amino acids derived from pyruvate including leucine, isoleucine, and valine. Thus, growth with alanine was an efficient means of labeling intracellular pools of pyruvate in this lithotroph. Cells were grown with 18% [U-(13)C]alanine, and the distribution of the isotope in the branched-chain amino acids was determined by (13)C-NMR. Carbons derived from pyruvate contained 14.5% (13)C, indicating that most of the cellular pyruvate was obtained from alanine. In contrast, carbons derived from acetyl-CoA contained only 3-5% (13)C, indicating that only small amounts of acetyl-CoA were formed from pyruvate. Thus, autotrophic acetyl-CoA biosynthesis continued even in the presence of an organic carbon source. Moreover, the labeling of acetyl-CoA was lower than would be predicted if pyruvate was a C-1 donor for acetyl-CoA biosynthesis. Carbon derived from the C-1 of acetyl-CoA contained less (13)C than carbon derived from the C-2 of acetyl-CoA, and this difference was attributed to the acetyl-CoA:CO(2) exchange activity of acetyl-CoA synthase. No enrichment was detected for the C-1 of valine, which was derived from the C-1 of pyruvate. This result was attributed to the pyruvate:CO(2) exchange activity of pyruvate oxidoreductase and may have important implications for isotope tracer studies utilizing pyruvate. Lastly, these results demonstrate that the breakdown of pyruvate by methanococci is very limited even under conditions where it is the sole nitrogen and major carbon source.
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Affiliation(s)
- Yu-Ling Yang
- Department of Microbiology, University of Georgia, Athens, GA 30602-2605, USA
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19
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Schultze M, Quiclet-Sire B, Kondorosi E, Virelizer H, Glushka JN, Endre G, Géro SD, Kondorosi A. Rhizobium meliloti produces a family of sulfated lipooligosaccharides exhibiting different degrees of plant host specificity. Proc Natl Acad Sci U S A 1992; 89:192-6. [PMID: 1729688 PMCID: PMC48202 DOI: 10.1073/pnas.89.1.192] [Citation(s) in RCA: 191] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
We have shown that a Rhizobium meliloti strain overexpressing nodulation genes excreted high amounts of a family of N-acylated and 6-O-sulfated N-acetyl-beta-1,4-D-glucosamine penta-, tetra-, and trisaccharide Nod factors. Either a C(16:2) or a C(16:3) acyl chain is attached to the nonreducing end subunit, whereas the sulfate group is bound to the reducing glucosamine. One of the tetrasaccharides is identical to the previously described NodRm-1 factor. The two pentasaccharides as well as NodRm-1 were purified and tested for biological activity. In the root hair deformation assay the pentasaccharides show similar activities on the host plants Medicago sativa and Melilotus albus and on the non-host plant Vicia sativa at a dilution of up to 0.01-0.001 microM, in contrast to NodRm-1, which displays a much higher specific activity for Medicago and Melilotus than for Vicia. The active concentration range of the pentasaccharides is more narrow on Medicago than on Melilotus and Vicia. In addition to root hair deformation, the different Nod factors were shown to induce nodule formation on M. sativa. We suggest that the production of a series of active signal molecules with different degrees of specificity might be important in controlling the symbiosis of R. meliloti with several different host plants or under different environmental conditions.
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Affiliation(s)
- M Schultze
- Institut des Sciences Végétales, Centre National de la Recherche Scientifique, Gif-sur-Yvette, France
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20
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Abstract
Maltose has been converted into 4-O-(2-amino-2-deoxy-alpha-D-glucopyranosyl)-L-idopyranuronic acid, 4-O-(2-amino-2-deoxy-alpha-D-glucopyranosyl)-D-glucopyranose, and 4-O-alpha-D-glucopyranosyl-L-idopyranose, the first two disaccharides being related structurally to biose sequences in heparin and heparan sulfate. Used as the starting material was a major product of the kinetic acetonation of maltose, namely, 2,3:5,6-di-O-isopropylidene-4-O-(4,6-O-isopropylidene-alpha-D-glucopyran osyl)-aldehydo-D-glucose dimethyl acetal. It was subjected to a sequence of transformation that included the introduction of a 2'-amino-2'-deoxy function into the glucosyl group, the inversion of C-5 in the glucose residue to give the L-ido configuration, oxidation at position 6, and cyclisation of the acyclic dimethyl acetal to give the desired pyranuronic acid. In the formation of the latter, the 5-O-levulinoyl substituent was found to be less prone to acyl migration to O-6 than more conventional ester groups. The relative acid labilities of the O-isopropylidene and dimethyl acetal groups are compared, and conformations of the acyclic residues of some disaccharide derivatives are discussed.
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Affiliation(s)
- J N Glushka
- Department of Chemistry, McGill University, Montreal, Quebec, Canada
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21
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Rej RN, Glushka JN, Chew W, Perlin AS. Chromic acid oxidation in the synthesis of uronic acids. Use of the O-levulinoyl group to minimize acyl migration. Carbohydr Res 1989. [DOI: 10.1016/0008-6215(89)84092-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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22
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Glushka JN, Gupta DN, Perlin AS. The conversion of maltose into disaccharides having 2-amino-2-deoxy-α-d-glucose and l-idose as constituent sugars, for the synthesis of model compounds related to heparin. Carbohydr Res 1983. [DOI: 10.1016/0008-6215(83)88371-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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