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Ohno S, Manabe N, Yamaguchi T, Uzawa J, Yamaguchi Y. Ribitol in Solution Is an Equilibrium of Asymmetric Conformations. Molecules 2021; 26:molecules26185471. [PMID: 34576942 PMCID: PMC8468352 DOI: 10.3390/molecules26185471] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 09/06/2021] [Accepted: 09/06/2021] [Indexed: 11/18/2022] Open
Abstract
Ribitol (C5H12O5), an acyclic sugar alcohol, is present on mammalian α-dystroglycan as a component of O-mannose glycan. In this study, we examine the conformation and dynamics of ribitol by database analysis, experiments, and computational methods. Database analysis reveals that the anti-conformation (180°) is populated at the C3–C4 dihedral angle, while the gauche conformation (±60°) is seen at the C2–C3 dihedral angle. Such conformational asymmetry was born out in a solid-state 13C-NMR spectrum of crystalline ribitol, where C1 and C5 signals are unequal. On the other hand, solution 13C-NMR has identical chemical shifts for C1 and C5. NMR 3J coupling constants and OH exchange rates suggest that ribitol is an equilibrium of conformations, under the influence of hydrogen bonds and/or steric hinderance. Molecular dynamics (MD) simulations allowed us to discuss such a chemically symmetric molecule, pinpointing the presence of asymmetric conformations evidenced by the presence of correlations between C2–C3 and C3–C4 dihedral angles. These findings provide a basis for understanding the dynamic structure of ribitol and the function of ribitol-binding enzymes.
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Affiliation(s)
- Shiho Ohno
- Division of Structural Glycobiology, Institute of Molecular Biomembrane and Glycobiology, Tohoku Medical and Pharmaceutical University, 4-4-1 Komatsushima, Aoba-ku, Sendai 981-8558, Miyagi, Japan; (S.O.); (N.M.)
| | - Noriyoshi Manabe
- Division of Structural Glycobiology, Institute of Molecular Biomembrane and Glycobiology, Tohoku Medical and Pharmaceutical University, 4-4-1 Komatsushima, Aoba-ku, Sendai 981-8558, Miyagi, Japan; (S.O.); (N.M.)
| | - Takumi Yamaguchi
- School of Materials Science, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi 923-1292, Ishikawa, Japan;
| | - Jun Uzawa
- Structural Glycobiology Team, RIKEN (The Institute of Physical and Chemical Research), 2-1 Hirosawa, Wako 351-0198, Saitama, Japan;
| | - Yoshiki Yamaguchi
- Division of Structural Glycobiology, Institute of Molecular Biomembrane and Glycobiology, Tohoku Medical and Pharmaceutical University, 4-4-1 Komatsushima, Aoba-ku, Sendai 981-8558, Miyagi, Japan; (S.O.); (N.M.)
- Structural Glycobiology Team, RIKEN (The Institute of Physical and Chemical Research), 2-1 Hirosawa, Wako 351-0198, Saitama, Japan;
- Correspondence: ; Tel.: +81-22-727-0208
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Glibstrup E, Pedersen CM. Synthesis of α-D-Gal pN 3-(1-3)-D-Gal pN 3: α- and 3- O-selectivity using 3,4-diol acceptors. Beilstein J Org Chem 2018; 14:2805-2811. [PMID: 30498530 PMCID: PMC6244312 DOI: 10.3762/bjoc.14.258] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Accepted: 10/30/2018] [Indexed: 12/22/2022] Open
Abstract
The motif α-D-GalpNAc-(1-3)-D-GalpNAc is very common in Nature and hence its synthesis highly relevant. The synthesis of its azido precursor has been studied and optimized in terms of steps, yields and selectivity. It has been found that glycosylation of the 3,4-diol acceptor is an advantage over the use of a 4-O-protected acceptor and that both regio- and anomeric selectivity is enhanced by bulky 6-O-protective groups. The acceptors and donors are made from common building blocks, limiting protective manipulations, and in this context, unavoidable side reactions.
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Affiliation(s)
- Emil Glibstrup
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen O, Denmark
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Early innate immunity to bacterial infection in the lung is regulated systemically by the commensal microbiota via nod-like receptor ligands. Infect Immun 2014; 82:4596-606. [PMID: 25135683 DOI: 10.1128/iai.02212-14] [Citation(s) in RCA: 131] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The commensal microbiota is a major regulator of the immune system. The majority of commensal bacteria inhabit the gastrointestinal tract and are known to regulate local mucosal defenses against intestinal pathogens. There is growing appreciation that the commensal microbiota also regulates immune responses at extraintestinal sites. Currently, however, it is unclear how this influences host defenses against bacterial infection outside the intestine. Microbiota depletion caused significant defects in the early innate response to lung infection by the major human pathogen Klebsiella pneumoniae. After microbiota depletion, early clearance of K. pneumoniae was impaired, and this could be rescued by administration of bacterial Nod-like receptor (NLR) ligands (the NOD1 ligand MurNAcTri(DAP) and NOD2 ligand muramyl dipeptide [MDP]) but not bacterial Toll-like receptor (TLR) ligands. Importantly, NLR ligands from the gastrointestinal, but not upper respiratory, tract rescued host defenses in the lung. Defects in early innate immunity were found to be due to reduced reactive oxygen species-mediated killing of bacteria by alveolar macrophages. These data show that bacterial signals from the intestine have a profound influence on establishing the levels of antibacterial defenses in distal tissues.
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Beisswenger C, Coyne CB, Shchepetov M, Weiser JN. Role of p38 MAP kinase and transforming growth factor-beta signaling in transepithelial migration of invasive bacterial pathogens. J Biol Chem 2007; 282:28700-28708. [PMID: 17650505 DOI: 10.1074/jbc.m703576200] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Streptococcus pneumoniae and Haemophilus influenzae are human pathogens that often asymptomatically colonize the mucosal surface of the upper respiratory tract, but also occasionally cause invasive disease. The ability of these species to traverse the epithelium of the airway mucosa was modeled in vitro using polarized respiratory epithelial cells in culture. Migration across the epithelial barrier was preceded by loss of transepithelial resistance. Membrane products of S. pneumoniae that included lipoteichoic acid induced disruption of the epithelial barrier in a Toll-like receptor 2-dependent manner. This result correlates with a recent genetic study that associates increased TLR2 signaling with increased rates of invasive pneumococcal disease in humans. Loss of transepithelial resistance by the TLR2 ligand correlated with activation of p38 MAP kinase and transforming growth factor (TGF)-beta signaling. Activation of p38 MAPK and TGF-beta signaling in epithelial cells upon nasal infection with S. pneumoniae was also demonstrated in vivo. Inhibition of either p38 MAPK or TGF-beta signaling was sufficient to inhibit the migration of S. pneumoniae or H. influenzae. Our data shows that diverse bacteria utilize common mechanisms, including MAPK and TGF-beta signaling pathways to disrupt epithelial barriers and promote invasion.
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Affiliation(s)
- Christoph Beisswenger
- Department of Microbiology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104
| | - Carolyn B Coyne
- Department of Pediatrics, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104
| | - Mikhail Shchepetov
- Department of Microbiology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104
| | - Jeffrey N Weiser
- Department of Microbiology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104; Department of Pediatrics, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104.
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Draing C, Pfitzenmaier M, Zummo S, Mancuso G, Geyer A, Hartung T, von Aulock S. Comparison of lipoteichoic acid from different serotypes of Streptococcus pneumoniae. J Biol Chem 2006; 281:33849-59. [PMID: 16943191 DOI: 10.1074/jbc.m602676200] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Pneumococcal lipoteichoic acid (LTA) is known to have a completely different chemical structure compared with that of Staphylococcus aureus: the polyglycerophosphate in the backbone is replaced in the pneumococcal LTA by a pentamer repeating unit consisting of one ribitol and a tetrasaccharide carrying the unusual substituents phosphocholine and N-acetyl-D-galactosamine. Neither D-alanine nor N-acetyl-D-glucosamine, which play central roles in the biological activity of the staphylococcal LTA, has been reported. The extraction using butanol is more gentle compared with the previously reported chloroform-methanol extraction and results in a higher yield of LTA. We characterized the LTA of two different strains of Streptococcus pneumoniae:R6 (serotype 2) and Fp23 (serotype 4). NMR analysis confirmed the structure of LTA from R6 but showed that its ribitol carries an N-acetyl-D-galactosamine substituent. The NMR data for the LTA from Fp23 indicate that this LTA additionally contains ribitol-bound D-alanine. Dose-response curves of the two pneumococcal LTAs in human whole blood revealed that LTA from Fp23 was significantly more potent than LTA from R6 with regard to the induction of all cytokines measured (tumor necrosis factor, interleukin-1 (IL-1), IL-8, IL-10, granulocyte colony-stimulating factor, and interferon gamma). However, other characteristics, such as lack of inhibition by endotoxin-specific LAL-F, Toll-like receptor 2 and not 4 dependence, and lack of stimulation of neutrophilic granulocytes, were shared by both LTAs. This is the first report of a difference in the structure of LTA between two pneumococcal serotypes resulting in different immunostimulatory potencies.
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Affiliation(s)
- Christian Draing
- Department of Biochemical Pharmacology, University of Konstanz, P. O. Box M668, 78457 Konstanz, Germany
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Hermann C, Spreitzer I, Schröder NWJ, Morath S, Lehner MD, Fischer W, Schütt C, Schumann RR, Hartung T. Cytokine induction by purified lipoteichoic acids from various bacterial species--role of LBP, sCD14, CD14 and failure to induce IL-12 and subsequent IFN-gamma release. Eur J Immunol 2002; 32:541-51. [PMID: 11828371 DOI: 10.1002/1521-4141(200202)32:2<541::aid-immu541>3.0.co;2-p] [Citation(s) in RCA: 97] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We have recently shown that highly purified lipoteichoic acid (LTA) represents a major immunostimulatory principle of Staphylococcus aureus. In order to test whether this translates to other bacterial species, we extracted and purified LTA from 12 laboratory-grown species. All LTA induced the release of TNF-alpha, IL-1beta, IL-6 and IL-10 in human whole blood. Soluble CD14 (sCD14) inhibited monokine induction by LTA but failed to confer LTA responsiveness for IL-6 and IL-8 release of human umbilical vein endothelial cells (HUVEC). In a competitive LPS-binding protein (LBP) binding assay, the IC(50) of the tested LTA preparations was up to 3,230-fold higher than for LPS. LBP enhanced TNF-alpha release of human peripheral blood mononuclear cells (PBMC) upon LPS but not LTA stimulation. These data demonstrate a differential role for the serum proteins LBP and sCD14 in the recognition of LPS and LTA. Different efficacies of various anti-CD14 antibodies against LPS vs. LTA-induced cytokine release suggest that the recognition sites of CD14 for LPS and LTA are distinct with a partial overlap. While the maximal achievable monokine release in response to LTA was comparable to LPS, all LTA induced significantly less IL-12 and IFN-gamma. IL-12 substitution increased LTA-inducible IFN-gamma release up to 180-fold, suggesting a critical role of poor LTA-inducible IL-12 for IFN-gamma formation. Pretreatment with IFN-gamma rendered galactosamine-sensitized mice sensitive to challenge with LTA. In conclusion, LTA compared to LPS, are weak inducers of IL-12 and subsequent IFN-gamma formation which might explain their lower toxicity in vivo.
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Affiliation(s)
- Corinna Hermann
- Biochemical Pharmacology, University of Konstanz, D-78457 Konstanz, Germany
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Hermann C, Spreitzer I, Schröder NWJ, Morath S, Lehner MD, Fischer W, Schütt C, Schumann RR, Hartung T. Cytokine induction by purified lipoteichoic acids from various bacterial species - Role of LBP, sCD14, CD14 and failure to induce IL-12 and subsequent IFN-γ release. Eur J Immunol 2002. [DOI: 10.1002/1521-4141(200202)32:2%3c541::aid-immu541%3e3.0.co;2-p] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Affiliation(s)
- W Fischer
- Institute of Biochemistry, Faculty of Medicine, University Erlangen-Nürnberg, Germany
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Xu Q, Mohan S, Bush CA. A flexible model for the cell wall polysaccharide of Streptococcus mitis J22 determined by three-dimensional 13C edited nuclear overhauser effect spectroscopy and 13C-1H long-range coupling constants combined with molecular modeling. Biopolymers 1998. [DOI: 10.1002/(sici)1097-0282(199603)38:3<339::aid-bip7>3.0.co;2-v] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Klein RA, Jónsdóttir SÓ, Egge H. Aspects of conformational mobility in charged oligosaccharides. ACTA ACUST UNITED AC 1997. [DOI: 10.1016/s0166-1280(97)00003-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Fischer W, Markwitz S, Labischinski H. Small-angle X-ray scattering analysis of pneumococcal lipoteichoic acid phase structure. EUROPEAN JOURNAL OF BIOCHEMISTRY 1997; 244:913-7. [PMID: 9108265 DOI: 10.1111/j.1432-1033.1997.00913.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
X-Ray-scattering analysis was performed on micelles of lipoteichoic acid from Streptococcus pneumoniae. This lipoteichoic acid differs from poly(glycerophosphate) and poly(glycosylglycerophosphate) lipoteichoic acids by a unique positively charged diacylglyceroglycolipid anchor and a complex structure of the hydrophilic chain which is composed of zwitterionic tetrasaccharide ribitol phosphate repeats each carrying two zwitterionic phosphocholine substituents. The size distribution of the lipoteichoic acid micelles was sufficiently homogenous to determine their size and some related molecular parameters by small-angle scattering analysis. Nearly independent on the ionic strength of the aqueous dispersion, an average micelle contained about 150 lipoteichoic acid molecules arranged in a spherical assembly with a diameter of about 23 nm, whereby the hydrophilic region occupied an outer shell of about 8.5 nm thickness. Taken this as the average chain length of LTA in the micelle and 7.2 repeats per chain, each repeat contributed about 1.2 nm to the thickness of the hydrophilic shell as compared to 2.4 nm for a fully extended chain conformation and 1.1 nm estimated for a more helical arrangement [Klein, R. A., Hartmann, R., Egge, H., Behr, T. & Fischer, W. (1994) Carbohydr. Res. 256, 189-222]. A comparison with the micelle of poly(glycerophosphate) lipoteichoic acid of Staphylococcus aureus suggests that the supramolecular structure is largely independent of the structure of the hydrophilic chain and solely dictated by the small cross-sectional area of the diacylglycerol moiety common to all lipoteichoic acids and lipoglycans of gram-positive bacteria.
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Affiliation(s)
- W Fischer
- Institut für Biochemie, Friedrich-Alexander Universität, Erlangen, Germany
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Mulloy B. High-field NMR as a technique for the determination of polysaccharide structures. Mol Biotechnol 1996; 6:241-65. [PMID: 9067973 DOI: 10.1007/bf02761706] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
NMR spectroscopy has played a developing role in the study of polysaccharide structures for over 30 years. Many new bacterial polysaccharide repeat unit structures have recently been published as a result of the application of modern NMR techniques. NMR can also be used to elucidate the structures of both regular and heterogeneous polysaccharides from fungal and plant sources, as well as complex glycosaminoglycans of animal origin. In addition to covalent structure, conformation and dynamics of polysaccharides are susceptible to NMR analysis, both in solution and in the solid state. Improvements in NMR technology with potential applications to polysaccharide studies hold promise for the future.
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Affiliation(s)
- B Mulloy
- Laboratory for Molecular Structure, National Institute for Biological Standards and Control, Hertfordshire, UK
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Greenberg JW, Fischer W, Joiner KA. Influence of lipoteichoic acid structure on recognition by the macrophage scavenger receptor. Infect Immun 1996; 64:3318-25. [PMID: 8757870 PMCID: PMC174224 DOI: 10.1128/iai.64.8.3318-3325.1996] [Citation(s) in RCA: 98] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Lipoteichoic acids (LTAs) belong to the immunostimulatory class of molecules of gram-positive bacteria (GPB). Previous investigations showed that the macrophage scavenger receptor (SR), a glycosylated trimeric transmembrane protein, binds directly to many GPB, possibly via LTA. SR binding to other ligands is dependent upon the spatial characteristics of the repeating negative charge of the ligand. We therefore investigated SR recognition of LTA species with various charge densities and distributions by determining the capacity of these LTAs to compete with the binding of metabolically labeled SR to beads coated with the known SR ligand polyguanylic acid. Staphylococcus aureus LTA, a classical LTA type (unbranched 1,3-linked polyglycerophosphate chain covalently bound to a membrane diacylglyceroglycolipid), had a 50% inhibitory concentration (IC50) for inhibition of SR binding of 0.84 microg/ml. When the S. aureus LTA was rendered more negatively charged by removal of ester-linked alanine from the polyglycerophosphate backbone, the IC50 dropped to 0.23 microg/ml. Other polyglycerophosphate LTAs from Enterococcus faecalis, Enterococcus faecium, Enterococcus hirae, Listeria monocytogenes, Listeria welshimeri, and Streptococcus sanguis showed IC50S of 0.5 to 2.1 microg/ml, supporting the role of negative charge in binding to SR. Accordingly, the zwitterionic LTA of Streptococcus pneumoniae and Clostridium innocuum LTA substituted with positively charged sugar residues had no binding capacity. Monoglycerophosphate branches, but not succinyl ester, affected binding of lipoglycans. The data presented above parallel the previous findings for whole organisms and support the role of surface-associated LTA as a major ligand of GPB for binding to SR. Whether binding of LTA and whole GPB to macrophages initiates uptake and degradation or results in signal transduction remains to be determined.
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Affiliation(s)
- J W Greenberg
- Infectious Disease Section, Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut 06520-8022, USA
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Xu Q, Mohan S, Bush CA. A flexible model for the cell wall polysaccharide of Streptococcus mitis J22 determined by three-dimensional 13C edited nuclear overhauser effect spectroscopy and 13C-1H long-range coupling constants combined with molecular modeling. Biopolymers 1996; 38:339-53. [PMID: 8906970 DOI: 10.1002/(sici)1097-0282(199603)38:3%3c339::aid-bip7%3e3.0.co;2-v] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
We report on the conformation of a tetrasaccharide fragment in the repeating subunit of the cell wall polysaccharide of Streptococcus mitis J22, a receptor for the lectin of Actinomyces viscosus T14V in a bacterial coaggregation that is important in the ecological interactions of oral bacteria. Although there is considerable overlap of the 1H-nmr signals, some cross peaks can be extracted from conventional two-dimensional nuclear Overhauser effect spectroscopy (NOESY) data on the polysaccharide. These data cannot be fit to a single conformation of the tetrasaccharide fragment. Therefore we have prepared a polysaccharide sample fully enriched in 13C from which we have determined accurate NOESY cross-peak volumes in a three-dimensional heteronuclear-resolved spectrum that allows accurate determination of many more NOESY cross peaks than does conventional two-dimensional spectroscopy. We have also used the 13C enriched polysaccharide to measure accurate values of long-range 13C-1H coupling constants that can be correlated with glycosidic dihedral angles. Molecular modeling calculations on the polysaccharide fragment, including molecular dynamics simulations, identify multiple low-energy conformations. This result is to be contrasted with previous calculations on blood group oligosaccharides in our laboratory using similar methods that showed relatively rigid conformations with little flexibility of the glycosidic linkages. The present NOESY and 3JCH data can be reconciled with a model for the antigenic tetrasaccharide in which three distinct conformations are in fast exchange. We propose that some carbohydrate epitopes such as those of the blood group oligosaccharides are relatively rigid while others such as the tetrasaccharide fragment in these studies exhibit much greater flexibility.
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Affiliation(s)
- Q Xu
- Department of Chemistry and Biochemistry, University of Maryland, Baltimore 21228, USA
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Klein RA, Hartmann R, Egge H, Behr T, Fischer W. The aqueous solution structure of a lipoteichoic acid from Streptococcus pneumoniae strain R6 containing 2,4-diamino-2,4,6-trideoxy-galactose: evidence for conformational mobility of the galactopyranose ring. Carbohydr Res 1996; 281:79-98. [PMID: 8839178 DOI: 10.1016/0008-6215(95)00336-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The 2D-NOESY spectra for the per-N-acetylated and the native lipoteichoic acid (LTA) oligomer from Streptococcus pneumoniae strain R6 clearly indicate a difference in conformation of the 2,4,6-trideoxy-galactopyranose ring. Whereas the 2,4-N-acetylated Gal24N adopts the usual 4C1 chair conformation, the native 2-N-acetyl-4-amino Gal24N exhibits conformational mobility with comparable populations in the 4C1 chair and 5S1 skew conformations, as determined using MD simulation for the partial trisaccharide Me-beta-D-Glc6P-(1-->3)-alpha-D-Gal24N-[6-PC]-(1-->4)-alpha- D-galNAc and from the intra-ring NOE effects. 31P-NMR spectra point to a strong electrostatic or hydrogen-bonding interaction between the free 4-NH2 group on the Gal24N and the negatively charged diester phosphate group between adjacent pentasaccharide repeating-units [Ribitol-(5-->6)-beta-D-Glc6P]. Molecular modelling and MD simulation experiments confirmed that such an interaction was feasible with the Gal24N galactopyranose ring in the inverted B1.4 or skew 5S1 conformation.
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Affiliation(s)
- R A Klein
- Institut für Physiologische Chemie der Universität Bonn, Germany
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16
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Abstract
Oligosaccharides represent a particularly challenging class of molecules for conformational analysis. Recent advances in experimental and theoretical methods have begun to yield further insight into their conformational behavior; however, general rules governing their conformational preferences have not yet emerged. X-ray and NMR techniques may provide vital insights into protein-bound oligosaccharide conformations, but these do not necessarily represent highly populated solution conformations. Moreover, an oligosaccharide's inherent flexibility and lack of strong intermolecular interactions places extreme demands on theoretical methods.
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Affiliation(s)
- R J Woods
- Complex Carbohydrate Research Center, University of Georgia, Athens 30602-4712, USA
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