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Lalithamaheswari B, Anu Radha C. Structural and conformational dynamics of human milk oligosaccharides, lacto- N-fucopentaose I and II, through molecular dynamics simulation. J Carbohydr Chem 2022. [DOI: 10.1080/07328303.2022.2150203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- B. Lalithamaheswari
- Research Laboratory of Molecular Biophysics, Department of Physics, School of Advanced Sciences, Vellore Institute of Technology, Vellore, Tamil Nadu, India
| | - C. Anu Radha
- Research Laboratory of Molecular Biophysics, Department of Physics, School of Advanced Sciences, Vellore Institute of Technology, Vellore, Tamil Nadu, India
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2
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Pseudo-glycoconjugates with a C-glycoside linkage. Adv Carbohydr Chem Biochem 2022; 82:35-77. [PMID: 36470649 DOI: 10.1016/bs.accb.2022.10.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Work by the author and colleagues has been focused on the development of pseudo-glycans (pseudo-glycoconjugates), in which the O-glycosidic linkage of the natural-type glycan structure is replaced by a C-glycosidic linkage. These analogs are not degraded by cellular glycoside hydrolases and are thus expected to be useful molecular tools that may maintain the original biological activity for a long period in the cell. However, their biological potential is not yet well understood because only a few pseudo glycans have so far been synthesized. This article aims to provide a bird's-eye view of our recent studies on the creation of C-glycoside analogs of ganglioside GM3 based on the CHF-sialoside linkage, and summarizes the chemical insights acquired during our stereoselective synthesis of the C-sialoside bond, ultimately leading to pseudo-GM3. Conformational analysis of the synthesized CHF-sialoside disaccharides confirmed that the anticipated conformational control by F-atom introduction was successful, and furthermore, enhanced the biological activity. In order to improve access to C-glycoside analogs based on pseudo-GM3, it is still important to streamline the synthesis process. With this in mind, we designed and developed a direct C-glycosylation method using atom-transfer radical coupling, and employed it in syntheses of pseudo-isomaltose and pseudo-KRN7000.
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Glycan binding and specificity of viral influenza neuraminidases by classical molecular dynamics and replica exchange molecular dynamics simulations. J Biomol Struct Dyn 2018; 37:3354-3365. [DOI: 10.1080/07391102.2018.1514326] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Murugan V, Parasuraman P, Selvin JFA, Gromiha MM, Fukui K, Veluraja K. Theoretical investigation on the binding specificity of fluorinated sialyldisaccharides Neu5Acα(2–3)Gal and Neu5Acα(2–6)Gal with influenza hemagglutinin H1 – A Molecular Dynamics Study. J Carbohydr Chem 2017. [DOI: 10.1080/07328303.2017.1365153] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Veeramani Murugan
- Department of Physics, Manonmaniam Sundaranar University, Tirunelveli, Tamilnadu, India
| | - Ponnusamy Parasuraman
- Department of Physical Sciences, Bannari Amman Institute of Technology, Erode, Tamilnadu, India
| | | | - Michael M. Gromiha
- Department of Biotechnology, Indian Institute of Technology Madras, Chennai, Tamilnadu, India
| | - Kazuhiko Fukui
- National Institute of Advanced Industrial Science and Technology (AIST), Molecular Profiling Research Center for Drug Discovery (molprof), 2-4-7 Aomi, Koto-ku, Tokyo, Japan
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Parasuraman P, Murugan V, Selvin JFA, Gromiha MM, Fukui K, Veluraja K. Insights into the binding specificity of wild type and mutated wheat germ agglutinin towards Neu5Acα(2-3)Gal: a study by in silico mutations and molecular dynamics simulations. J Mol Recognit 2015; 27:482-92. [PMID: 24984865 DOI: 10.1002/jmr.2369] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Revised: 02/02/2014] [Accepted: 02/02/2014] [Indexed: 02/06/2023]
Abstract
Wheat germ agglutinin (WGA) is a plant lectin, which specifically recognizes the sugars NeuNAc and GlcNAc. Mutated WGA with enhanced binding specificity can be used as biomarkers for cancer. In silico mutations are performed at the active site of WGA to enhance the binding specificity towards sialylglycans, and molecular dynamics simulations of 20 ns are carried out for wild type and mutated WGAs (WGA1, WGA2, and WGA3) in complex with sialylgalactose to examine the change in binding specificity. MD simulations reveal the change in binding specificity of wild type and mutated WGAs towards sialylgalactose and bound conformational flexibility of sialylgalactose. The mutated polar amino acid residues Asn114 (S114N), Lys118 (G118K), and Arg118 (G118R) make direct and water mediated hydrogen bonds and hydrophobic interactions with sialylgalactose. An analysis of possible hydrogen bonds, hydrophobic interactions, total pair wise interaction energy between active site residues and sialylgalactose and MM-PBSA free energy calculation reveals the plausible binding modes and the role of water in stabilizing different binding modes. An interesting observation is that the binding specificity of mutated WGAs (cyborg lectin) towards sialylgalactose is found to be higher in double point mutation (WGA3). One of the substituted residues Arg118 plays a crucial role in sugar binding. Based on the interactions and energy calculations, it is concluded that the order of binding specificity of WGAs towards sialylgalactose is WGA3 > WGA1 > WGA2 > WGA. On comparing with the wild type, double point mutated WGA (WGA3) exhibits increased specificity towards sialylgalactose, and thus, it can be effectively used in targeted drug delivery and as biological cell marker in cancer therapeutics.
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Affiliation(s)
- Ponnusamy Parasuraman
- Department of Physics, Manonmaniam Sundaranar University, Tirunelveli, 627 012, India
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Ray GJ, Ravenscroft N, Siekmann J, Zhang Z, Sanders P, Shaligram U, Szabo CM, Kosma P. Complete structural elucidation of an oxidized polysialic acid drug intermediate by nuclear magnetic resonance spectroscopy. Bioconjug Chem 2014; 25:665-76. [PMID: 24679150 DOI: 10.1021/bc400456g] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Polysialic acid (PSA) is a high molecular weight glycan composed of repeat units of α(2→8) linked 5-N-acetyl-neuraminic acid. Mild periodate oxidation of PSA selectively targets the end sialic acid ring containing three adjacent alcohols generating a putative aldehyde, which can be used for terminal attachment of PSA to therapeutic proteins. The work presented here permitted complete NMR peak assignments of not only the repeat units, but also the two terminal units at each end of oxidized PSA, an intermediate, which can be used to improve drug performance. The assignments were made using a variety of NMR techniques on oligomers of sialic acid as well as oxidized PSA with molecular masses of 4 and 20 kDa. This enabled structure elucidation that showed the actual moiety formed was not the expected aldehyde or its hydrate, but is a hemiacetal between the oxidation site on the terminal sialic acid ring and the penultimate ring. The existence of a hemiacetal structure has major implications on stability, reactivity, and conjugation chemistry of oxidized PSA. The assignment process also revealed deuterium exchange of the axial hydrogen at the 3- (methylene) position of the ring, which was in agreement with the literature.
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Affiliation(s)
- G Joseph Ray
- Baxter Healthcare Corporation , Round Lake, 60073, Illinois, United States
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7
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Sialyldisaccharide conformations: a molecular dynamics perspective. J Comput Aided Mol Des 2012; 26:375-85. [DOI: 10.1007/s10822-012-9563-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2011] [Accepted: 03/18/2012] [Indexed: 11/27/2022]
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Veluraja K, Seethalakshmi AN. Dynamics of sialyl Lewisa in aqueous solution and prediction of the structure of the sialyl Lewisa–SelectinE complex. J Theor Biol 2008; 252:15-23. [DOI: 10.1016/j.jtbi.2007.12.024] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2007] [Revised: 12/24/2007] [Accepted: 12/24/2007] [Indexed: 11/25/2022]
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Attrill H, Imamura A, Sharma RS, Kiso M, Crocker PR, van Aalten DMF. Siglec-7 undergoes a major conformational change when complexed with the alpha(2,8)-disialylganglioside GT1b. J Biol Chem 2006; 281:32774-83. [PMID: 16895906 DOI: 10.1074/jbc.m601714200] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The siglecs are a group of mammalian sialic acid binding receptors expressed predominantly in the immune system. The CD33-related siglecs show complex recognition patterns for sialylated glycans. Siglec-7 shows a preference for alpha(2,8)-disialylated ligands and provides a structural template for studying the key interactions that drive this selectivity. We have co-crystallized Siglec-7 with a synthetic oligosaccharide corresponding to the alpha(2,8)-disialylated ganglioside GT1b. The crystal structure of the complex offers a first glimpse into how this important family of lectins binds the structurally diverse gangliosides. The structure reveals that the C-C' loop, a region implicated in previous studies as driving siglec specificity, undergoes a dramatic conformational shift, allowing it to interact with the underlying neutral glycan core of the ganglioside. The structural data in combination with mutagenesis studies show that binding of the ganglioside is driven by extensive hydrophobic contacts together with key polar interactions and that the binding site structure is complementary to preferred solution conformations of GT1b.
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Affiliation(s)
- Helen Attrill
- Division of Biological Chemistry and Molecular Microbiology, School of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland, United Kingdom
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Sharmila DJS, Veluraja K. Conformations of higher gangliosides and their binding with cholera toxin - investigation by molecular modeling, molecular mechanics, and molecular dynamics. J Biomol Struct Dyn 2006; 23:641-56. [PMID: 16615810 DOI: 10.1080/07391102.2006.10507089] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Molecular mechanics and molecular dynamics studies are performed to investigate the conformational preference of cell surface higher gangliosides (GT1A and GT1B) and their interaction with Cholera Toxin. The water mediated hydrogen bonding network exists between sugar residues in gangliosides. An integrated molecular modeling, molecular mechanics, and molecular dynamics calculation of cholera toxin complexed with GT1A and GT1B reveal that, the active site of cholera toxin can accommodate these higher gangliosides. Direct and water mediated hydrogen bonding interactions stabilize these binding modes and play an essential role in defining the order of specificity for different higher ganglioside towards cholera toxin. This study identifies that the binding site of cholera toxin is shallow and can accommodate a maximum of two NeuNAc residues. The NeuNAc binding site of cholera toxin may be crucial for the design of inhibitors that can prevent the infection of cholera.
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Veluraja K, Margulis CJ. Conformational Dynamics of Sialyl Lewisxin Aqueous Solution and Its Interaction with SelectinE. A Study by Molecular Dynamics. J Biomol Struct Dyn 2005; 23:101-11. [PMID: 15918681 DOI: 10.1080/07391102.2005.10507051] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Three dimensional structures of sialyl Lewis(x) (SLe(x)) in aqueous solution and bound to selectinE are described based on an exhaustive conformational analysis and several long molecular dynamics simulations using different glycosidic regions as starting conformations. It appears from this study that when the oligosaccharide is free in solution the NeuNAcalpha(2-3)Gal segment favors glycosidic conformation in three different regions in the (Phi,Psi) plane with propensity of populations in the ratio 1:8:1. Each one of these structures is characteristically stabilized by specific hydrogen bonding interaction between NeuNAc and Gal. On the other hand, the Gal-GlcNAc-Fuc segment can exist in four different conformational states. Based on the topology of SLe(x) we are able to predict that out of all the allowed conformations in solution only two of these structures possess a geometry that would fit without steric clashes into the binding location of selectinE. In both of these binding modes, segment Gal-GlcNAc-Fuc adopts a unique conformation. The only difference between the two SLe(x) conformers that can successfully bind to selectinE is given by two possible regions in glycosidic space in the fragment NeuNAcalpha(2-3)Gal. A large conformational departure from the crystallographic data is observed for two lysine residues at the binding site of selectinE. These two residues play an important role when SLe(x) binds selectinE in aqueous solution. These findings help reconcile the X-ray data, in which these residues appear to be 1 nm away from SLe(x), with recent liquid NMR data reporting couplings between these protein residues and the sugar.
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Jeya Sundara Sharmila D, Veluraja K. Disialogangliosides and Their Interaction with Cholera Toxin—Investigation by Molecular Modeling, Molecular Mechanics and Molecular Dynamics. J Biomol Struct Dyn 2004; 22:299-313. [PMID: 15473704 DOI: 10.1080/07391102.2004.10507002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Molecular mechanics and molecular dynamics studies are performed to investigate the conformational preference of cell surface disialogangliosides (GD1A, GD1B and GD3) in aqueous environment. The molecular mechanics calculation reveals that water mediated hydrogen bonding network plays a significant role in the structural stabilization of GD1A, GD1B and GD3. These water mediated hydrogen bonds not only exist between neighboring residues but also exist between residues that are separated by 2 to 3 residues in between. The conformational energy difference between different conformational states of gangliosides correlates very well with the number of water mediated and direct hydrogen bonds. The spatial flexibility of NeuNAc of gangliosides at the binding site of cholera toxin is worked out. The NeuNAc has a limited allowed eulerian space at the binding site of Cholera Toxin (2.4%). The molecular modeling, molecular mechanics and molecular dynamics of disialoganglioside-cholera toxin complex reveal that cholera toxin can accommodate the disialoganglioside GD1A in three different modes. A single mode of binding is permissible for GD1B and GD3. Direct and water mediated hydrogen bonding interactions stabilizes these binding modes and play an essential role in defining the order of specificity for different disialogangliosides towards cholera toxin. This study not only provides models for the disialoganglioside-cholera toxin complexes but also identifies the NeuNAc binding site as a site for design of inhibitors that can restrict the pathogenic activity of cholera toxin.
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Sharmila DJS, Veluraja K. Monosialogangliosides and Their Interaction with Cholera Toxin—Investigation by Molecular Modeling and Molecular Mechanics. J Biomol Struct Dyn 2004; 21:591-614. [PMID: 14692802 DOI: 10.1080/07391102.2004.10506951] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Molecular mechanics and molecular dynamics studies are performed to investigate the conformational preference of cell surface monosialogangliosides (GM3, GM2 and GM1) in aqueous environment. Water mediated hydrogen bonding network plays a significant role in the structural stabilization of GM3, GM2 and GM1. The spatial flexibility of NeuNAc of gangliosides at the binding site of cholera toxin reveals a limited allowed eulerian space of 2.4% with a much less allowed eulerian space (1.4%) for external galactose of GM1. The molecular mechanics of monosialoganglioside-cholera toxin complex reveals that cholera toxin can accommodate the monosialogangliosides in three different modes. Direct and water mediated hydrogen bonding interactions stabilize these binding modes and play an essential role in defining the order of specificity for different monosialogangliosides towards cholera toxin. This study identifies the NeuNAc binding site as a site for design of inhibitors that can restrict the pathogenic activity of cholera toxin.
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