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Song J, Tu G, Liu Y, Liu S, Zhang Y, Yang W, Pang X, Chen X, Liang H, Zhang J, Ma B. Hydroxyl groups introducing NMR strategy for structural elucidation of a heptasaccharide isolated from Trillium tschonoskii. Carbohydr Res 2024; 549:109359. [PMID: 39709710 DOI: 10.1016/j.carres.2024.109359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2024] [Revised: 11/26/2024] [Accepted: 12/16/2024] [Indexed: 12/24/2024]
Abstract
A heptasaccharide was isolated from an active fraction of Trillium tschonoskii using HILIC and high-temperature PGC chromatography methods. UHPLC-Q/TOF-MS analysis gave this oligosaccharide a degree of polymerization (DP) of 7 and MS/MS showed that it has a six-carbon aldehyde glucan structure with the possible chain 1 → 4 connected. The structure was determined by series 1D and 2D NMR in two solvents D2O and DMSO‑d6. Using 1H resonances of the -OH groups as the starting point and HSQC-TOCSY on the covalent structure definition for structural elucidation allowed this heptasaccharide to be uncovered. This heptasaccharide was elucidated as maltoheptaose via complete assignment of 1H and 13C with jigsaw H-C-OH pieces produced by HSQC-TOCSY at increasing mixing time. The significance of identifying maltoheptaose in Trillium tschonoskii indicates the high potential of -OH introducing strategy for other oligosaccharides' structural determination with relatively higher DP.
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Affiliation(s)
- Juan Song
- Beijing Institute of Radiation Medicine, Beijing, 100850, China
| | - Guangzhong Tu
- Beijing Institute of Microchemistry, Beijing, 100091, China
| | - Yue Liu
- Beijing Institute of Radiation Medicine, Beijing, 100850, China
| | - Si Liu
- Beijing Institute of Radiation Medicine, Beijing, 100850, China; Shandong University of Traditional Chinese Medicine, Jinan, 250355, China
| | - Yuting Zhang
- Beijing Institute of Radiation Medicine, Beijing, 100850, China
| | - Wenxi Yang
- Beijing Institute of Radiation Medicine, Beijing, 100850, China
| | - Xu Pang
- Beijing Institute of Radiation Medicine, Beijing, 100850, China
| | - Xiaojuan Chen
- Beijing Institute of Radiation Medicine, Beijing, 100850, China
| | - Haizhen Liang
- Beijing Institute of Radiation Medicine, Beijing, 100850, China
| | - Jie Zhang
- Beijing Institute of Radiation Medicine, Beijing, 100850, China
| | - Baiping Ma
- Beijing Institute of Radiation Medicine, Beijing, 100850, China; Shandong University of Traditional Chinese Medicine, Jinan, 250355, China.
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2
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Charisiadis P, Venianakis T, Papaemmanouil CD, Primikyri A, Tzakos AG, Siskos MG, Gerothanassis IP. On the Use of Strong Proton Donors as a Tool for Overcoming Line Broadening in NMR: A Comment. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2024. [PMID: 39632552 DOI: 10.1002/mrc.5499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2024] [Revised: 11/16/2024] [Accepted: 11/19/2024] [Indexed: 12/07/2024]
Abstract
Overcoming line broadening of labile protons and achieving high-resolution NMR spectra is crucial for the structural and conformational analysis of organic molecules. Recently, Ma et al. (Magn. Reson. Chem. 2024, 62, 198-207) demonstrated the effectiveness of 2,2,2-trifluoroacetic acid (TFA) in sharpening NMR signals for nitrogen-containing compounds which exhibit prototropic tautomerization or conformational isomerism using high molar ratio of [acids]/[solute] ~ 5 to 200. In this commentary, we provide an overview of earlier publications and highlight the extensive applications of TFA in enhancing NMR resolution across a variety of organic functional groups, with the use of very small ratios of [acids]/[solute] ~ 10-3 to 10-2. The prospects for the unequivocal structure analysis using labile protons as the starting point will be analyzed.
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Affiliation(s)
- Pantelis Charisiadis
- Section of Organic Chemistry and Biochemistry, Department of Chemistry, University of Ioannina, Ioannina, Greece
| | - Themistoklis Venianakis
- Section of Organic Chemistry and Biochemistry, Department of Chemistry, University of Ioannina, Ioannina, Greece
| | - Christina D Papaemmanouil
- Section of Organic Chemistry and Biochemistry, Department of Chemistry, University of Ioannina, Ioannina, Greece
| | - Alexandra Primikyri
- Section of Organic Chemistry and Biochemistry, Department of Chemistry, University of Ioannina, Ioannina, Greece
| | - Andreas G Tzakos
- Section of Organic Chemistry and Biochemistry, Department of Chemistry, University of Ioannina, Ioannina, Greece
| | - Michael G Siskos
- Section of Organic Chemistry and Biochemistry, Department of Chemistry, University of Ioannina, Ioannina, Greece
| | - Ioannis P Gerothanassis
- Section of Organic Chemistry and Biochemistry, Department of Chemistry, University of Ioannina, Ioannina, Greece
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3
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Rane DV, García-Calvo L, Kristiansen KA, Bruheim P. Zic-HILIC MS/MS Method for NADomics Provides Novel Insights into Redox Homeostasis in Escherichia coli BL21 Under Microaerobic and Anaerobic Conditions. Metabolites 2024; 14:607. [PMID: 39590843 PMCID: PMC11596675 DOI: 10.3390/metabo14110607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2024] [Revised: 10/25/2024] [Accepted: 11/05/2024] [Indexed: 11/28/2024] Open
Abstract
Background: Nicotinamide adenine dinucleotide (NAD+), its precursors, and its derivatives (collectively NADome) play a crucial role in cellular processes and maintain redox homeostasis. Understanding the dynamics of these metabolic pools and redox reactions can provide valuable insights into metabolic functions, especially cellular regulation and stress response mechanisms. The accurate quantification of these metabolites is challenging due to the interconversion between the redox forms. Methods: Our laboratory previously developed a zwitterionic hydrophilic interaction liquid chromatography (zic-HILIC)-tandem mass spectrometry method for the quantification of five essential pyridine nucleotides, including NAD+ derivatives and it's reduced forms, with 13C isotope dilution and matrix-matched calibration. In this study, we have improved the performance of the chromatographic method and expanded its scope to twelve analytes for a comprehensive view of NAD+ biosynthesis and utilization. The analytical method was validated and applied to investigate Escherichia coli BL21 under varying oxygen supplies including aerobic, microaerobic, and anaerobic conditions. Conclusions: The intracellular absolute metabolite concentrations ranged over four orders of magnitude with NAD+ as the highest abundant, while its precursors were much less abundant. The composition of the NADome at oxygen-limited conditions aligned more with that in the anaerobic conditions rather than in the aerobic phase. Overall, the NADome was quite homeostatic and E. coli rapidly, but in a minor way, adapted the metabolic activity to the challenging shift in the growth conditions and achieved redox balance. Our findings demonstrate that the zic-HILIC-MS/MS method is sensitive, accurate, robust, and high-throughput, providing valuable insights into NAD+ metabolism and the potential significance of these metabolites in various biological contexts.
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Affiliation(s)
| | | | | | - Per Bruheim
- Department of Biotechnology and Food Science, NTNU Norwegian University of Science and Technology, N-7491 Trondheim, Norway; (D.V.R.); (K.A.K.)
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Franz AH, Bromley KS, Aung ET, Do SQL, Rosenblatt HM, Watson AJ. NMR Coupling Constants, Karplus Equations, and Adjusted MD Statistics: Detecting Diagnostic Torsion Angles for the Solution Geometry of 6-[α-d-Mannopyranosyl]-d-Mannopyranose (Mannobiose). MAGNETIC RESONANCE IN CHEMISTRY : MRC 2024. [PMID: 39415469 DOI: 10.1002/mrc.5483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2024] [Revised: 09/21/2024] [Accepted: 09/23/2024] [Indexed: 10/18/2024]
Abstract
The quantitative solution conformations of 2-(hydroxymethyl)-tetrahydropyran, α-methyl-d-mannopyranoside, and 6-[α-d-mannopyranosyl]-d-mannopyranose (mannobiose) are described. Parametrized Karplus equations for redundant spin pairs across the terminal ω-torsion and the glycosidic ω-torsion for mannobiose are developed, including ω/θ-hypersurfaces for the terminal hydroxymethylene group. Experimental NMR data, algorithmic spectral simulation (clustered Hamiltonian method), molecular dynamics (MD) simulations (GLYCAM06), energy minimizations by DFT, and adjusted torsion angle populations weighted over the Karplus-type equations are used. We demonstrate that spectral simulation is a powerful tool in the refinement of initial J values obtained from static GAIO DFT calculations. We also show that only as few as one of multiple redundant torsions can be diagnostic for conformational analysis of the disaccharide.
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Affiliation(s)
- Andreas H Franz
- Department of Chemistry, University of the Pacific, Stockton, California, USA
| | - Kendall S Bromley
- Department of Chemistry, University of the Pacific, Stockton, California, USA
| | - Ei T Aung
- Department of Chemistry, University of the Pacific, Stockton, California, USA
| | - Stephen Q L Do
- Department of Chemistry, University of the Pacific, Stockton, California, USA
| | - Hana M Rosenblatt
- Department of Chemistry, University of the Pacific, Stockton, California, USA
| | - Amelia J Watson
- Department of Chemistry, University of the Pacific, Stockton, California, USA
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5
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Tse TJ, Chicilo F, Wiens DJ, Shen J, Anleu Alegria J, Kim YJ, Hong JY, Kim JK, Shin EC, Reaney MJT, Shim YY. Production of α-Glycerylphosphorylcholine in Fermented Roots, Tubers, and Fruits. Foods 2024; 13:3085. [PMID: 39410120 PMCID: PMC11475080 DOI: 10.3390/foods13193085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2024] [Revised: 09/22/2024] [Accepted: 09/24/2024] [Indexed: 10/20/2024] Open
Abstract
Vegetables and fruits, high in starch and sugars, are promising substrates for bioethanol production, but can also yield valuable nootropic compounds, such as α-glycerylphosphorylcholine (α-GPC). This compound is a known cognitive enhancer that works by increasing the release of acetylcholine, a neurotransmitter essential for learning and memory. In this study, select root and tuber crops, as well as fruits, were subjected to Saccharomyces cerevisiae fermentation to observe the co-production of ethanol and α-GPC. The ethanol yields from these substrates were comparable to those from wheat (var. AC Andrew), ranging from 30.44 g/L (beet) to 70.04 g/L (lotus root). Aside from ethanol, α-GPC was also produced, with purple top turnip yielding 0.91 g/L, the second highest concentration after wheat (used as a reference), which produced 1.25 g/L. Although α-GPC yields in the tested substrates were lower than those from cereal grains (e.g., wheat and barley), a noteworthy observation was the production of methanol in many of these substrates. Methanol was detected in all feedstocks except wheat, with concentrations ranging from 0.10 g/L (cassava) to 1.69 g/L (purple top turnip). A linear regression analysis revealed a strong correlation between methanol and α-GPC content (R2 = 0.876; slope = 0.52), suggesting a potential link in their biosynthetic pathways. These feedstocks not only proved effective as substrates for bioethanol production, but also showed potential for generating value-added compounds such as α-GPC. This dual-purpose potential presents new market opportunities for producers by leveraging both biofuel and nootropic compound production. Furthermore, the observed relationship between methanol and α-GPC production warrants further investigation to elucidate the metabolic pathways involved.
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Affiliation(s)
- Timothy J. Tse
- Department of Food and Bioproduct Sciences, University of Saskatchewan, 51 Campus Drive, Saskatoon, SK S7N 5A8, Canada; (F.C.); (D.J.W.); (J.S.); (J.A.A.); (M.J.T.R.)
| | - Farley Chicilo
- Department of Food and Bioproduct Sciences, University of Saskatchewan, 51 Campus Drive, Saskatoon, SK S7N 5A8, Canada; (F.C.); (D.J.W.); (J.S.); (J.A.A.); (M.J.T.R.)
| | - Daniel J. Wiens
- Department of Food and Bioproduct Sciences, University of Saskatchewan, 51 Campus Drive, Saskatoon, SK S7N 5A8, Canada; (F.C.); (D.J.W.); (J.S.); (J.A.A.); (M.J.T.R.)
| | - Jianheng Shen
- Department of Food and Bioproduct Sciences, University of Saskatchewan, 51 Campus Drive, Saskatoon, SK S7N 5A8, Canada; (F.C.); (D.J.W.); (J.S.); (J.A.A.); (M.J.T.R.)
| | - Javier Anleu Alegria
- Department of Food and Bioproduct Sciences, University of Saskatchewan, 51 Campus Drive, Saskatoon, SK S7N 5A8, Canada; (F.C.); (D.J.W.); (J.S.); (J.A.A.); (M.J.T.R.)
| | - Young Jun Kim
- Department of Food and Biotechnology, Korea University, 2511 Sejong-ro, Sejong 30019, Republic of Korea; (Y.J.K.); (J.K.K.)
| | - Ji Youn Hong
- Department of Food Regulatory Science, Korea University, 2511 Sejong-ro, Sejong 30019, Republic of Korea;
| | - Jae Kyeom Kim
- Department of Food and Biotechnology, Korea University, 2511 Sejong-ro, Sejong 30019, Republic of Korea; (Y.J.K.); (J.K.K.)
| | - Eui-Cheol Shin
- Department of Food Science, Gyeongsang National University, 501 Jinju-daero, Jinju 52828, Republic of Korea;
| | - Martin J. T. Reaney
- Department of Food and Bioproduct Sciences, University of Saskatchewan, 51 Campus Drive, Saskatoon, SK S7N 5A8, Canada; (F.C.); (D.J.W.); (J.S.); (J.A.A.); (M.J.T.R.)
- Department of Food and Biotechnology, Korea University, 2511 Sejong-ro, Sejong 30019, Republic of Korea; (Y.J.K.); (J.K.K.)
- Prairie Tide Diversified Inc., 102 Melville St., Saskatoon, SK S7J 0R1, Canada
| | - Youn Young Shim
- Department of Food and Bioproduct Sciences, University of Saskatchewan, 51 Campus Drive, Saskatoon, SK S7N 5A8, Canada; (F.C.); (D.J.W.); (J.S.); (J.A.A.); (M.J.T.R.)
- Department of Food and Biotechnology, Korea University, 2511 Sejong-ro, Sejong 30019, Republic of Korea; (Y.J.K.); (J.K.K.)
- Prairie Tide Diversified Inc., 102 Melville St., Saskatoon, SK S7J 0R1, Canada
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Hobsteter AW, Irazoqui AP, Gonzalez A, Picco AS, Rubert AA, Buitrago CG, Lo Fiego MJ, Silbestri GF. Acetylated galactopyranosyl N-heterocyclic monocarbene complexes of Silver(I) as novel anti-proliferative agents in a rhabdomyosarcoma cell line. Bioorg Med Chem 2024; 107:117756. [PMID: 38759255 DOI: 10.1016/j.bmc.2024.117756] [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: 04/15/2024] [Revised: 05/08/2024] [Accepted: 05/10/2024] [Indexed: 05/19/2024]
Abstract
Herein, four silver(I) complexes bearing acetylated d-galactopyranoside-based N-heterocyclic carbene ligands were synthesized and fully characterized by elemental analysis, NMR, and X-ray photoelectron spectroscopy. All complexes were obtained with an anomeric β-configuration and as monocarbene species. In this study, we investigated the biological effects of the silver(I) complexes 2a-d on the human rhabdomyosarcoma cell line, RD. Our results show concentration-dependent effects on cell density, growth inhibition, and activation of key signaling pathways such as Akt 1/2, ERK 1/2, and p38-MAPK, indicating their potential as anticancer agents. Notably, at 35.5 µM, the complexes induced mitochondrial network disruption, as observed with 2b and 2c, whereas with 2a, this disruption was accompanied by nuclear content release. These results provide insight into the utility of carbohydrate incorporated NHC complexes of silver(I) as new agents in cancer therapy.
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Affiliation(s)
- Ariana W Hobsteter
- INQUISUR, Departamento de Química, Universidad Nacional del Sur (UNS-CONICET), 8000 Bahía Blanca, Argentina
| | - Ana P Irazoqui
- INBIOSUR (UNS-CONICET), Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur, 8000 Bahía Blanca, Argentina; Comisión de Investigaciones Científicas de la provincia de Buenos Aires (CIC PBA), Argentina.
| | - Agustina Gonzalez
- INBIOSUR (UNS-CONICET), Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur, 8000 Bahía Blanca, Argentina
| | - Agustín S Picco
- INIFTA, Fac. de Cs. Exactas, Universidad Nacional de La Plata-CONICET, 1900 La Plata, Argentina
| | - Aldo A Rubert
- INIFTA, Fac. de Cs. Exactas, Universidad Nacional de La Plata-CONICET, 1900 La Plata, Argentina
| | - Claudia G Buitrago
- INBIOSUR (UNS-CONICET), Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur, 8000 Bahía Blanca, Argentina
| | - Marcos J Lo Fiego
- INQUISUR, Departamento de Química, Universidad Nacional del Sur (UNS-CONICET), 8000 Bahía Blanca, Argentina.
| | - Gustavo F Silbestri
- INQUISUR, Departamento de Química, Universidad Nacional del Sur (UNS-CONICET), 8000 Bahía Blanca, Argentina
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Zhang S, Cao Z, Fan P, Sun W, Xiao Y, Zhang P, Wang Y, Huang S. Discrimination of Disaccharide Isomers of Different Glycosidic Linkages Using a Modified MspA Nanopore. Angew Chem Int Ed Engl 2024; 63:e202316766. [PMID: 38116834 DOI: 10.1002/anie.202316766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2023] [Revised: 12/17/2023] [Accepted: 12/19/2023] [Indexed: 12/21/2023]
Abstract
Disaccharides are composed of two monosaccharide subunits joined by a glycosidic linkage in an α or β configuration. Different combinations of isomeric monosaccharide subunits and different glycosidic linkages result in different isomeric disaccharide products. Thus, direct discrimination of these disaccharide isomers from a mixture is extremely difficult. In this paper, a hetero-octameric Mycobacterium smegmatis porin A (MspA) nanopore conjugated with a phenylboronic acid (PBA) adapter was applied for disaccharide sensing, with which three most widely known disaccharides in nature, including sucrose, lactose and maltose, were clearly discriminated. Besides, all six isomeric α-D-glucopyranosyl-D-fructoses, differing only in their glycosidic linkages, were also well resolved. Assisted by a custom machine learning algorithm, a 0.99 discrimination accuracy is achieved. Nanopore discrimination of disaccharide isomers with different glycosidic linkages, which has never been previously demonstrated, is inspiring for nanopore saccharide sequencing. This sensing capacity was also applied in direct identification of isomaltulose additives in a commercial sucrose-free yogurt, from which isomaltulose, lactose and L-lactic acid were simultaneously detected.
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Affiliation(s)
- Shanyu Zhang
- State Key Laboratory of Analytical Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China
- Chemistry and Biomedicine Innovation Center (ChemBIC), Nanjing University, Nanjing, 210023, China
| | - Zhenyuan Cao
- State Key Laboratory of Analytical Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China
- Chemistry and Biomedicine Innovation Center (ChemBIC), Nanjing University, Nanjing, 210023, China
| | - Pingping Fan
- State Key Laboratory of Analytical Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China
- Chemistry and Biomedicine Innovation Center (ChemBIC), Nanjing University, Nanjing, 210023, China
| | - Wen Sun
- State Key Laboratory of Analytical Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China
- Chemistry and Biomedicine Innovation Center (ChemBIC), Nanjing University, Nanjing, 210023, China
| | - Yunqi Xiao
- State Key Laboratory of Analytical Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China
- Chemistry and Biomedicine Innovation Center (ChemBIC), Nanjing University, Nanjing, 210023, China
| | - Panke Zhang
- State Key Laboratory of Analytical Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China
| | - Yuqin Wang
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, 210023, China
- Institute for the Environment and Health, Nanjing University Suzhou Campus, Suzhou, 215163, China
| | - Shuo Huang
- State Key Laboratory of Analytical Chemistry for Life Sciences, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, 210023, China
- Chemistry and Biomedicine Innovation Center (ChemBIC), Nanjing University, Nanjing, 210023, China
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8
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Xie X, Huang D, Li Z. Bioproduction of Rare d-Allulose from d-Glucose via Borate-Assisted Isomerization. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2024; 72:3036-3044. [PMID: 38299460 DOI: 10.1021/acs.jafc.3c07100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2024]
Abstract
d-Allulose is a low-calorie functional rare sugar with excellent processing suitability and unique physiological efficacy. d-Allulose is primarily produced from d-fructose through enzymatic epimerization, facing the constraints of a low conversion yield and high production cost. In this study, a double-enzyme cascade system with tetraborate-assisted isomerization was constructed for the efficient production of d-allulose from inexpensive d-glucose. With the introduction of sodium tetraborate (STB), capable of forming complexes with diol-bearing sugars, the conversion yield of d-allulose from d-glucose substantially escalated from the initial 17.37% to 44.97%. Furthermore, d-allulose was found to exhibit the most pronounced binding affinity for STB with an association constant of 1980.51 M-1, notably surpassing that of d-fructose (183.31 M-1) and d-glucose (35.37 M-1). Additionally, the structural analysis of the sugar-STB complexes demonstrated that d-allulose reacted with STB via the cis 2,3-hydroxyl groups in the α-furanose form. Finally, the mechanism underlying STB-assisted isomerization was proposed, emphasizing the preferential formation of an allulose-STB complex that effectively shifts the isomerization equilibrium to the allulose side, thereby resulting in high yield of d-allulose. Such an STB-facilitated isomerization system would also provide a guidance for the cost-effective synthesis of other rare sugars.
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Affiliation(s)
- Xiaofang Xie
- Department of Food Science and Technology, National University of Singapore, 117542, Singapore
- National University of Singapore (Suzhou) Research Institute, 377 Lin Quan Street, Suzhou, Jiangsu 215123, China
| | - Dejian Huang
- Department of Food Science and Technology, National University of Singapore, 117542, Singapore
- National University of Singapore (Suzhou) Research Institute, 377 Lin Quan Street, Suzhou, Jiangsu 215123, China
| | - Zhaofeng Li
- School of Food Science and Technology, Jiangnan University, Wuxi 214122, China
- Yixing Institute of Food and Biotechnology Co., Ltd, Yixing, Jiangsu 214200, China
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9
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Abstract
Glycans, carbohydrate molecules in the realm of biology, are present as biomedically important glycoconjugates and a characteristic aspect is that their structures in many instances are branched. In determining the primary structure of a glycan, the sugar components including the absolute configuration and ring form, anomeric configuration, linkage(s), sequence, and substituents should be elucidated. Solution state NMR spectroscopy offers a unique opportunity to resolve all these aspects at atomic resolution. During the last two decades, advancement of both NMR experiments and spectrometer hardware have made it possible to unravel carbohydrate structure more efficiently. These developments applicable to glycans include, inter alia, NMR experiments that reduce spectral overlap, use selective excitations, record tilted projections of multidimensional spectra, acquire spectra by multiple receivers, utilize polarization by fast-pulsing techniques, concatenate pulse-sequence modules to acquire several spectra in a single measurement, acquire pure shift correlated spectra devoid of scalar couplings, employ stable isotope labeling to efficiently obtain homo- and/or heteronuclear correlations, as well as those that rely on dipolar cross-correlated interactions for sequential information. Refined computer programs for NMR spin simulation and chemical shift prediction aid the structural elucidation of glycans, which are notorious for their limited spectral dispersion. Hardware developments include cryogenically cold probes and dynamic nuclear polarization techniques, both resulting in enhanced sensitivity as well as ultrahigh field NMR spectrometers with a 1H NMR resonance frequency higher than 1 GHz, thus improving resolution of resonances. Taken together, the developments have made and will in the future make it possible to elucidate carbohydrate structure in great detail, thereby forming the basis for understanding of how glycans interact with other molecules.
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Affiliation(s)
- Carolina Fontana
- Departamento
de Química del Litoral, CENUR Litoral Norte, Universidad de la República, Paysandú 60000, Uruguay
| | - Göran Widmalm
- Department
of Organic Chemistry, Arrhenius Laboratory, Stockholm University, S-106 91 Stockholm, Sweden
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10
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Lin P, W-M Fan T, Lane AN. NMR-based isotope editing, chemoselection and isotopomer distribution analysis in stable isotope resolved metabolomics. Methods 2022; 206:8-17. [PMID: 35908585 PMCID: PMC9539636 DOI: 10.1016/j.ymeth.2022.07.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 07/18/2022] [Accepted: 07/25/2022] [Indexed: 11/20/2022] Open
Abstract
NMR is a very powerful tool for identifying and quantifying compounds within complex mixtures without the need for individual standards or chromatographic separation. Stable Isotope Resolved Metabolomics (or SIRM) is an approach to following the fate of individual atoms from precursors through metabolic transformation, producing an atom-resolved metabolic fate map. However, extracts of cells or tissue give rise to very complex NMR spectra. While multidimensional NMR experiments may partially overcome the spectral overlap problem, additional tools may be needed to determine site-specific isotopomer distributions. NMR is especially powerful by virtue of its isotope editing capabilities using NMR active nuclei such as 13C, 15N, 19F and 31P to select molecules containing just these atoms in a complex mixture, and provide direct information about which atoms are present in identified compounds and their relative abundances. The isotope-editing capability of NMR can also be employed to select for those compounds that have been selectively derivatized with an NMR-active stable isotope at particular functional groups, leading to considerable spectral simplification. Here we review isotope analysis by NMR, and methods of chemoselection both for spectral simplification, and for enhanced isotopomer analysis.
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Affiliation(s)
- Penghui Lin
- Center for Environmental and Systems Biochemistry, University of Kentucky, Lexington, KY 40536, USA
| | - Teresa W-M Fan
- Center for Environmental and Systems Biochemistry, University of Kentucky, Lexington, KY 40536, USA; Department of Toxicology and Cancer Biology, University of Kentucky, Lexington, KY 40536, USA
| | - Andrew N Lane
- Center for Environmental and Systems Biochemistry, University of Kentucky, Lexington, KY 40536, USA; Department of Toxicology and Cancer Biology, University of Kentucky, Lexington, KY 40536, USA.
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11
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Yoshimura S, Tanaka H, Kawabata S, Kozawa J, Takahashi H, Hidaka Y, Hotta M, Kashiwagi N, Tomiyama N. Effect of urinary glucose concentration and pH on signal intensity in magnetic resonance images. Jpn J Radiol 2022; 40:930-938. [PMID: 35396668 PMCID: PMC8993672 DOI: 10.1007/s11604-022-01273-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2022] [Accepted: 03/16/2022] [Indexed: 11/26/2022]
Abstract
Purpose With advances in anti-diabetes drugs, increasing numbers of patients have high urinary glucose concentrations, which may alter magnetic resonance (MR) signal intensity. We sought to elucidate the effect of urinary glucose concentration and pH on transverse relaxation and MR signal intensity. Materials and methods The transverse relaxation rate (R2) was measured in samples with different glucose concentrations (in vitro) and in the urinary bladder of seven patients with diabetes and nine healthy volunteers (in vivo). The glucose concentration and pH in the in vitro samples and urine were measured. The signal intensity ratio of the bladder to adjacent tissues was obtained on T2-weighted imaging (WI), T1WI, and MR urography (in vivo). To clarify the effect of pH further, the urine of two healthy subjects was adjusted with acid and/or base to obtain various pH values (ex vivo). Results R2 increased significantly with high glucose concentrations in the in vitro study. In the in vivo study, high glucose concentration (p < 0.001) and low pH (p = 0.005) were significantly associated with high R2. R2 was higher (p = 0.002) and the signal in maximum-intensity projection images of MR urography was lower (p = 0.005) in patients with diabetes than in healthy subjects. Ex vivo study revealed that a decrease in pH in acid portion resulted in increased R2. Conclusion High concentrations of urinary glucose and low pH both enhance transverse relaxation, which, in turn, causes low signal intensity in urinary bladder on long echo time (TE) images, such as MR urography. Radiologists should be aware of this phenomenon when interpreting abnormally low-intensity bladders on long TE images.
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Affiliation(s)
- Sho Yoshimura
- Division of Health Science, Osaka University Graduate School of Medicine, 1-7 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Hisashi Tanaka
- Division of Health Science, Osaka University Graduate School of Medicine, 1-7 Yamadaoka, Suita, Osaka, 565-0871, Japan.
| | - Shuichi Kawabata
- Department of Medical Radiological Technology, Osaka University Hospital, 2-15 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Junji Kozawa
- Department of Metabolic Medicine, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Hiroto Takahashi
- Center for Twin Research, Graduate School of Medicine, 1-7 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Yoh Hidaka
- Laboratory for Clinical Investigation, Osaka University Hospital, 2-15 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Masaki Hotta
- Laboratory for Clinical Investigation, Osaka University Hospital, 2-15 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Nobuo Kashiwagi
- Department of Future Diagnostic Radiology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Noriyuki Tomiyama
- Department of Diagnostic and Interventional Radiology, Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
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12
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Santagata G, Cimmino A, Poggetto GD, Zannini D, Masi M, Emendato A, Surico G, Evidente A. Polysaccharide Based Polymers Produced by Scabby Cankered Cactus Pear ( Opuntia ficus-indica L.) Infected by Neofusicoccum batangarum: Composition, Structure, and Chemico-Physical Properties. Biomolecules 2022; 12:89. [PMID: 35053237 PMCID: PMC8773635 DOI: 10.3390/biom12010089] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Revised: 12/29/2021] [Accepted: 01/01/2022] [Indexed: 02/04/2023] Open
Abstract
Neofusiccocum batangarum is the causal agent of scabby canker of cactus pear (Opuntia ficus-indica L.). The symptoms of this disease are characterized by crusty, perennial cankers, with a leathery, brown halo. Characteristically, a viscous polysaccharide exudate, caking on contact with air, leaks from cankers and forms strips or cerebriform masses on the surface of cactus pear cladodes. When this polysaccharide mass was partial purified, surprisingly, generated a gel. The TLC analysis and the HPLC profile of methyl 2-(polyhydroxyalkyl)-3-(o-tolylthiocarbomoyl)-thiazolidine-4R-carboxylates obtained from the mixture of monosaccharides produced by acid hydrolysis of the three EPSs examined in this research work [the polysaccharide component of the exudate (EPSC) and the EPSs extracted from asymptomatic (EPSH) and symptomatic (EPSD) cladodes] showed the presence of d-galactose, l-rhamnose, and d-glucose in a 1:1:0.5 ratio in EPSC while d-galactose, l-rhamnose, d-glucose, and d-xylose at the same ratio were observed in EPSH and EPSD. The presence of uronic acid residues in EPSC was also showed by solid state NMR and IR investigation. Furthermore, this manuscript reports the chemical-physical characterization of the gel produced by the infected cactus pear.
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Affiliation(s)
- Gabriella Santagata
- Istituto per i Polimeri Compositi e Biomateriali, CNR, Via Campi Flegrei 34, Comprensorio “A. Olivetti”, 80078 Pozzuoli (NA), Italy; (G.D.P.); (D.Z.)
| | - Alessio Cimmino
- Dipartimento di Scienze Chimiche, Università di Napoli Federico II, Complesso Universitario Monte Sant’Angelo, 80126 Napoli, Italy; (M.M.); (A.E.)
| | - Giovanni Dal Poggetto
- Istituto per i Polimeri Compositi e Biomateriali, CNR, Via Campi Flegrei 34, Comprensorio “A. Olivetti”, 80078 Pozzuoli (NA), Italy; (G.D.P.); (D.Z.)
| | - Domenico Zannini
- Istituto per i Polimeri Compositi e Biomateriali, CNR, Via Campi Flegrei 34, Comprensorio “A. Olivetti”, 80078 Pozzuoli (NA), Italy; (G.D.P.); (D.Z.)
| | - Marco Masi
- Dipartimento di Scienze Chimiche, Università di Napoli Federico II, Complesso Universitario Monte Sant’Angelo, 80126 Napoli, Italy; (M.M.); (A.E.)
| | - Alessandro Emendato
- Dipartimento di Farmacia, Università di Napoli Federico II, Via D. Montesano 49, 80131 Napoli, Italy;
| | - Giuseppe Surico
- Dipartimento di Scienze e Tecnologie Agrarie, Alimentari, Ambientali e Forestali, Università di Firenze, Piazzale delle Cascine 28, 50144 Firenze, Italy;
| | - Antonio Evidente
- Dipartimento di Scienze Chimiche, Università di Napoli Federico II, Complesso Universitario Monte Sant’Angelo, 80126 Napoli, Italy; (M.M.); (A.E.)
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13
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Dumouilla V, Dussap CG. Online analysis of D-glucose and D-mannose aqueous mixtures using Raman spectroscopy: an in silico and experimental approach. Bioengineered 2021; 12:4420-4431. [PMID: 34308749 PMCID: PMC8806848 DOI: 10.1080/21655979.2021.1955550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Accepted: 07/08/2021] [Indexed: 11/30/2022] Open
Abstract
Raman spectroscopy was applied to an aqueous solution containing D-mannose and D-glucose at a fixed dry matter content. The Raman measurement apparatus was adapted online at the industrial scale to monitor a bioprocess including an epimerization reaction. Online Raman spectroscopy and deconvolution techniques were successfully applied to monitor in real time the D-mannose and D-glucose concentrations using the Raman shifts at 960 cm-1 and 974 cm-1 respectively. The two anomeric forms, α and β of D-mannose in the pyranose conformation were quantified. In silico analysis of vibrational frequencies and Raman intensities of hydrated structure of D-mannose and D-glucose in the pyranose form for α and β anomers were carried out using a two-step procedure. First molecular dynamics was used to generate the theoretical carbohydrates' structures keeping the experimental dry matter content, then quantum mechanics was used to compute the Raman frequencies and intensities. Computed vibrational frequencies are in satisfactory agreement with the experimental spectra considering a hydration shell approach. Raman intensities are qualitatively in accordance with the experimental data. The interpretation of Raman frequencies and intensities led to acceptable results regarding the current possible structures of D-mannose and D-glucose in aqueous solution. Online Raman spectroscopy coupled with in silico approaches such as quantum mechanics and molecular dynamics methodology is proved to be a valuable tool to quantify the carbohydrates and stereoisomers content in complex aqueous mixtures. This methodology offers a new way to monitor any bioprocesses that encounter aqueous mixtures of D-glucose and D-mannose.
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Affiliation(s)
- Vincent Dumouilla
- CNRS, SIGMA Clermont, Institut Pascal, Université Clermont Auvergne, Clermont-Ferrand, France
- Biotechnology and Process Department, Roquettes Frères, Lestrem, France
| | - Claude Gilles Dussap
- CNRS, SIGMA Clermont, Institut Pascal, Université Clermont Auvergne, Clermont-Ferrand, France
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14
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Novakovic M, Battistel MD, Azurmendi HF, Concilio MG, Freedberg DI, Frydman L. The Incorporation of Labile Protons into Multidimensional NMR Analyses: Glycan Structures Revisited. J Am Chem Soc 2021; 143:8935-8948. [PMID: 34085814 PMCID: PMC8297728 DOI: 10.1021/jacs.1c04512] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
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Glycan structures
are often stabilized by a repertoire of hydrogen-bonded
donor/acceptor groups, revealing longer-lived structures that could
represent biologically relevant conformations. NMR provides unique
data on these hydrogen-bonded networks from multidimensional experiments
detecting cross-peaks resulting from through-bond (TOCSY) or through-space
(NOESY) interactions. However, fast OH/H2O exchange, and
the spectral proximity among these NMR resonances, hamper the use
of glycans’ labile protons in such analyses; consequently,
studies are often restricted to aprotic solvents or supercooled aqueous
solutions. These nonphysiological conditions may lead to unrepresentative
structures or to probing a small subset of accessible conformations
that may miss “active” glycan conformations. Looped,
projected spectroscopy (L-PROSY) has been recently shown to substantially
enhance protein NOESY and TOCSY cross-peaks, for 1Hs that
undergo fast exchange with water. This study shows that even larger
enhancements can be obtained for rapidly exchanging OHs in saccharides,
leading to the retrieval of previously undetectable 2D TOCSY/NOESY
cross-peaks with nonlabile protons. After demonstrating ≥300%
signal enhancements on model monosaccharides, these experiments were
applied at 1 GHz to elucidate the structural network adopted by a
sialic acid homotetramer, used as a model for α,2–8 linked
polysaccharides. High-field L-PROSY NMR enabled these studies at higher
temperatures and provided insight previously unavailable from lower-field
NMR investigations on supercooled samples, involving mostly nonlabile
nuclei. Using L-PROSY’s NOEs and other restraints, a revised
structural model for the homotetramer was obtained combining rigid
motifs and flexible segments, that is well represented by conformations
derived from 40 μs molecular dynamics simulations.
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Affiliation(s)
- Mihajlo Novakovic
- Department of Chemical and Biological Physics, Weizmann Institute of Science, 76100 Rehovot, Israel
| | - Marcos D Battistel
- Laboratory of Bacterial Polysaccharides, Center for Biologics Evaluation and Research, Food and Drug Administration, 10903 New Hampshire Avenue, Silver Spring, Maryland 20993, United States
| | - Hugo F Azurmendi
- Laboratory of Bacterial Polysaccharides, Center for Biologics Evaluation and Research, Food and Drug Administration, 10903 New Hampshire Avenue, Silver Spring, Maryland 20993, United States
| | - Maria-Grazia Concilio
- Department of Chemical and Biological Physics, Weizmann Institute of Science, 76100 Rehovot, Israel
| | - Darón I Freedberg
- Laboratory of Bacterial Polysaccharides, Center for Biologics Evaluation and Research, Food and Drug Administration, 10903 New Hampshire Avenue, Silver Spring, Maryland 20993, United States
| | - Lucio Frydman
- Department of Chemical and Biological Physics, Weizmann Institute of Science, 76100 Rehovot, Israel
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15
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Abstract
As barley and oat production have recently increased in Canada, it has become prudent to investigate these cereal crops as potential feedstocks for alcoholic fermentation. Ethanol and other coproduct yields can vary substantially among fermented feedstocks, which currently consist primarily of wheat and corn. In this study, the liquified mash of milled grains from 28 barley (hulled and hull-less) and 12 oat cultivars were fermented with Saccharomyces cerevisiae to determine concentrations of fermentation products (ethanol, isopropanol, acetic acid, lactic acid, succinic acid, α-glycerylphosphorylcholine (α-GPC), and glycerol). On average, the fermentation of barley produced significantly higher amounts of ethanol, isopropanol, acetic acid, succinic acid, α-GPC, and glycerol than that of oats. The best performing barley cultivars were able to produce up to 78.48 g/L (CDC Clear) ethanol and 1.81 g/L α-GPC (CDC Cowboy). Furthermore, the presence of milled hulls did not impact ethanol yield amongst barley cultivars. Due to its superior ethanol yield compared to oats, barley is a suitable feedstock for ethanol production. In addition, the accumulation of α-GPC could add considerable value to the fermentation of these cereal crops.
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16
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Secondary metabolites, antibacterial and antioxidant properties of the leaf extracts of Acacia rigidula benth. and Acacia berlandieri benth. SN APPLIED SCIENCES 2021. [DOI: 10.1007/s42452-021-04513-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
AbstractThe use of plants as sources for novel antimicrobial as well as antioxidant agents offers advantages. Plants are readily accessible and inexpensive, extracts or compounds from plant sources often demonstrate high level of biological activities. Previous studies have reported antibacterial and antifungal activities within the Fabaceae family that included Acacia species. This study aims to determine presence of antibacterial activity, antioxidant activity, and the secondary metabolites of sequential solvent extracts (acetone, methanol, and acetic acid) of Acacia berlandieri and Acacia rigidula leaves. The antibacterial activity was investigated using a disc diffusion assay. The ferric thiocyanate method was used to assess the ability of all extracts to prevent oxidation. Qualitative phytochemical tests, NMR, IR, and UV–Vis spectroscopy were done to identify potential secondary metabolites. P. alcalifaciens (p < 0.001), E. faecalis (p < 0.01), S. aureus (p < 0.001), and Y. enterocolitica (p < 0.001) were significantly inhibited by A. rigidula extracts when compared to A. berlandieri extracts. A. rigidula’s acetone extract exhibited the significantly (p < 0.001) highest inhibition of peroxidation, 42%. Qualitative phytochemical tests showed positive results for presence of phenols, flavonoids, saponins, terpenes and tannins. NMR, IR, and UV–Vis spectroscopy revealed chemical structures found in flavonoids, saponins, terpenes and tannins, supporting the results of qualitative phytochemical tests. A. berlandieri and A. rigidula leaf extracts have revealed presence of medicinally valued bioactive components. The results of this study provide a basis for further investigations of the A. rigidula leaf extracts. A. rigidula leaf extracts have the potential to serve as a source of novel antimicrobial and antioxidant agents.
Graphic abstract
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17
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In-depth spectral characterization of antioxidative (1,3)-β-D-glucan from the mycelium of an identified tiger milk mushroom Lignosus rhinocerus strain ABI in a stirred-tank bioreactor. BIOCATALYSIS AND AGRICULTURAL BIOTECHNOLOGY 2020. [DOI: 10.1016/j.bcab.2019.101455] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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18
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Gimeno A, Valverde P, Ardá A, Jiménez-Barbero J. Glycan structures and their interactions with proteins. A NMR view. Curr Opin Struct Biol 2019; 62:22-30. [PMID: 31835069 PMCID: PMC7322516 DOI: 10.1016/j.sbi.2019.11.004] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2019] [Revised: 11/05/2019] [Accepted: 11/07/2019] [Indexed: 12/28/2022]
Abstract
Carbohydrate molecules are essential actors in key biological events, being involved as recognition points for cell-cell and cell-matrix interactions related to health and disease. Despite outstanding advances in cryoEM, X-ray crystallography and NMR still remain the most employed techniques to unravel their conformational features and to describe the structural details of their interactions with biomolecular receptors. Given the intrinsic flexibility of saccharides, NMR methods are of paramount importance to deduce the extent of motion around their glycosidic linkages and to explore their receptor-bound conformations. We herein present our particular view on the latest advances in NMR methodologies that are permitting to magnify their applications for deducing glycan conformation and dynamics and understanding the recognition events in which there are involved.
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Affiliation(s)
- Ana Gimeno
- CIC bioGUNE, Bizkaia Technology Park, Building 800, 48162 Derio, Bizkaia, Spain
| | - Pablo Valverde
- CIC bioGUNE, Bizkaia Technology Park, Building 800, 48162 Derio, Bizkaia, Spain
| | - Ana Ardá
- CIC bioGUNE, Bizkaia Technology Park, Building 800, 48162 Derio, Bizkaia, Spain
| | - Jesús Jiménez-Barbero
- CIC bioGUNE, Bizkaia Technology Park, Building 800, 48162 Derio, Bizkaia, Spain; Ikerbasque, Basque Foundation for Science, 48013 Bilbao, Bizkaia, Spain; Department of Organic Chemistry II, University of the Basque Country, UPV/EHU, 48940 Leioa, Bizkaia, Spain
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19
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Rönnols J, Engström O, Schnupf U, Säwén E, Brady JW, Widmalm G. Inter-residual Hydrogen Bonding in Carbohydrates Unraveled by NMR Spectroscopy and Molecular Dynamics Simulations. Chembiochem 2019; 20:2519-2528. [PMID: 31066963 DOI: 10.1002/cbic.201900301] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Indexed: 12/15/2022]
Abstract
Carbohydrates, also known as glycans in biological systems, are omnipresent in nature where they as glycoconjugates occur as oligo- and polysaccharides linked to lipids and proteins. Their three-dimensional structure is defined by two or three torsion angles at each glycosidic linkage. In addition, transglycosidic hydrogen bonding between sugar residues may be important. Herein we investigate the presence of these inter-residue interactions by NMR spectroscopy in D2 O/[D6 ]DMSO (70:30) or D2 O and by molecular dynamics (MD) simulations with explicit water as solvent for disaccharides with structural elements α-d-Manp-(1→2)-d-Manp, β-d-GlcpNAc-(1→2)-d-Manp, and α-d-Glcp-(1→4)-β-d-Glcp, all of which have been suggested to exhibit inter-residue hydrogen bonding. For the disaccharide β-d-GlcpNAc-(1→2)-β-d-Manp-OMe, the large extent of O5'⋅⋅⋅HO3 hydrogen bonding as seen from the MD simulation is implicitly supported by the 1 H NMR chemical shift and 3 JHO3,H3 value of the hydroxy proton. In the case of α-d-Glcp-(1→4)-β-d-Glcp-OMe, the existence of a transglycosidic hydrogen bond O2'⋅⋅⋅HO3 was proven by the presence of a cross-peak in 1 H,13 C HSQC-TOCSY experiments as a result of direct TOCSY transfer between HO3 of the reducing end residue and H2' (detected at C2') of the terminal residue. The occurrence of inter-residue hydrogen bonding, albeit transient, is judged important for the stabilization of three-dimensional structures, which may be essential in maintaining a conformational state for carbohydrate-protein interactions of glycans to take place in biologically important environments.
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Affiliation(s)
- Jerk Rönnols
- Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, 106 91, Stockholm, Sweden
| | - Olof Engström
- Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, 106 91, Stockholm, Sweden
| | - Udo Schnupf
- Department of Chemistry and Biochemistry, Bradley University, Peoria, IL, 61625, USA
| | - Elin Säwén
- Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, 106 91, Stockholm, Sweden
| | - John W Brady
- Department of Food Science, Cornell University, Ithaca, NY, 14853, USA
| | - Göran Widmalm
- Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, 106 91, Stockholm, Sweden
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