3946-01-8Relevant articles and documents
Amide Cis-trans isomerization in aqueous solutions of methyl N -Formyl- d -glucosaminides and Methyl N -Acetyl- d -glucosaminides: Chemical equilibria and exchange kinetics
Hu, Xiaosong,Zhang, Wenhui,Carmichael, Ian,Serianni, Anthony S.
, p. 4641 - 4652 (2010)
Amide cis-trans isomerization (CTI) in methyl 2-deoxy-2-acylamido-d- glucopyranosides was investigated by 1H and 13C NMR spectroscopy. Singly 13C-labeled methyl 2-deoxy-2-formamido-d- glucopyranoside (MeGlcNFm) anomers provided standard 1H and 13C chemical shifts and 1H-1H and 13C-13C spin-coupling constants for cis and trans amides that are detected readily in aqueous solution. Equipped with this information, doubly 13C-labeled methyl 2-deoxy-2-acetamido-d-glucopyranoside (MeGlcNAc) anomers were investigated, leading to the detection and quantification of cis and trans amides in this biologically important aminosugar. In comparison to MeGlcNFm anomers, the percentage of cis amide in aqueous solutions of MeGlcNAc anomers is small (～23% for MeGlcNFm versus ～1.8% for MeGlcNAc at 42 °C) but nevertheless observable with assistance from 13C-labeling. Temperature studies gave thermodynamic parameters δG°, δH°, and δS° for cis-trans interconversion in MeGlcNFm and MeGlcNAc anomers. Cis/trans equilibria depended on anomeric configuration, with solutions of α-anomers containing less cis amide than those of β-anomers. Confirmation of the presence of cis amide in MeGlcNAc solutions derived from quantitative 13C saturation transfer measurements of CTI rate constants as a function of solution temperature, yielding activation parameters Eact, δG° ?, δH°-, and δS° ? for saccharide CTI. Rate constants for the conversion of trans to cis amide in MeGlcNFm and MeGlcNAc anomers ranged from 0.02 to 3.59 s-1 over 31-85 °C, compared to 0.24-80 s-1 for the conversion of cis to trans amide over the same temperature range. Energies of activation ranged from 16-19 and 19-20 kcal/mol for the cis → trans and trans → cis processes, respectively. Complementary DFT calculations on MeGlcNFm and MeGlcNAc model structures were conducted to evaluate the effects of an acyl side chain and anomeric structure, as well as C2-N2 bond rotation, on CTI energetics. These studies show that aqueous solutions of GlcNAc-containing structures contain measurable amounts of both cis and trans amides, which may influence their biological properties.
A de Novo-Designed Monomeric, Compact Three-Helix-Bundle Protein on a Carbohydrate Template
Malik, Leila,Nygaard, Jesper,Cristensen, Niels J.,Madsen, Charlotte S.,R?sner, Heike I.,Kragelund, Birthe B.,Hoiberg-Nielsen, Rasmus,Streicher, Werner W.,Arleth, Lise,Thulstrup, Peter W.,Jensen, Knud J.
, p. 1905 - 1918 (2015)
De novo design and chemical synthesis of proteins and of other artificial structures that mimic them is a central strategy for understanding protein folding and for accessing proteins with new functions. We have previously described carbohydrates that act as templates for the assembly of artificial proteins, so-called carboproteins. The hypothesis is that the template preorganizes the secondary structure elements and directs the formation of a tertiary structure, thus achieving structural economy in the combination of peptide, linker, and template. We speculate that the structural information from the template could facilitate protein folding. Here we report the design and synthesis of three-helix-bundle carboproteins on deoxyhexopyranosides. The carboproteins were analyzed by CD, analytical ultracentrifugation (AUC), small-angle X-ray scattering (SAXS), and NMR spectroscopy, and this revealed the formation of the first compact and folded monomeric carboprotein, distinctly different from a molten globule. En route to this carboprotein we observed a clear effect originating from the template on protein folding.
Stoichiometric C6-oxidation of hyaluronic acid by oxoammonium salt TEMPO+Cl- in an aqueous alkaline medium
Ponedel'Kina, Irina Yu,Khaibrakhmanova, Elvira A.,Tyumkina, Tatyana V.,Romadova, Irina V.,Odinokov, Victor N.
, p. 69 - 76 (2015)
This paper reports the selective oxidation of hyaluronic acid (HA) by stoichiometric quantity of 2,2,6,6-tetramethylpiperidine-1-oxoammonium chloride (TEMPO+) in aqueous alkaline medium. High efficiency of the HA oxidation and quantitative yield of carboxy-HA per starting TEMPO+, as well as unusual behavior of the oxidation system generating an oxygen upon alkali-induced oxoammonium chloride decomposition are demonstrated. The scheme for HA oxidation involving both TEMPO+ and oxygen produced upon the TEMPO+Cl- decomposition and/or air oxygen is proposed. For comparison, the data on stoichiometric oxidation of such substrates as dermatan sulfate, water-soluble potato starch, methyl 2-acetamido-2-deoxy-β-d-glucopyranoside and ethanol are presented.
Synthesis and Study of Molecular Assemblies Formed by 4,6-O-(2-Phenylethylidene)-Functionalized d -Glucosamine Derivatives
Chen, Anji,Adhikari, Surya B.,Mays, Kellie,Wang, Guijun
, p. 8076 - 8089 (2017)
Low-molecular-weight gelators are interesting small molecules with potential applications as advanced materials. Carbohydrate-based small molecular gelators are especially useful because they are derived from renewable resources and are more likely to be biocompatible and biodegradable. Various 4,6-benzylidene acetal protected α-methyl 2-d-glucosamine derivatives have been found to be effective low-molecular-weight gelators. To understand the influence of the 4,6-benzylidene acetal functional group toward molecular self-assembly and to obtain effective molecular gelators, we synthesized and analyzed a new series of d-glucosamine derivatives in which the phenyl group of the acetal is replaced by a benzyl group. The homologation of the acetal protection from aromatic to aliphatic functional groups allows us to probe the effect of increasing structural flexibility on molecular self-assembly and gelation. In this study, nine representative amides and nine urea analogs were synthesized, and their gelation properties were analyzed in a series of organic solvents and aqueous solutions. The resulting amide and urea derivatives are versatile organogelators forming gels in toluene, ethanol, isopropanol, ethylene glycol, and aqueous mixtures of organic solvents. More interestingly, the amide analogs are also effective gelators for pump oil and engine oil. NMR spectroscopy at variable temperatures was used to analyze the molecular assemblies and intermolecular forces. The selected gelators with several drug and dye molecules in DMSO and water were studied for their effectiveness of encapsulation and release of these agents.
O-Acetylated sugars in the gas phase: stability, migration, positional isomers and conformation
Allouche, Abdul-Rahman,Chambert, Stéphane,Compagnon, Isabelle,Gharbi, Amira,Rouillon, Jean,Schindler, Baptiste,Yeni, Oznur
, p. 1016 - 1022 (2022/02/01)
O-Acetylations are functional modifications which can be found on different hydroxyl groups of glycans and which contribute to the fine tuning of their biological activity. Localizing the acetyl modifications is notoriously challenging in glycoanalysis, in particular because of their mobility: loss or migration of the acetyl group may occur through the analytical workflow. Whereas migration conditions in the condensed phase have been rationalized, little is known about the suitability of Mass Spectrometry to retain and resolve the structure of O-acetylated glycan isomers. Here we used the resolving power of infrared ion spectroscopy in combination with ab initio calculations to assess the structure of O-acetylated monosaccharide ions in the gaseous environment of a mass analyzer. N-Acetyl glucosamines were synthetized with an O-acetyl group in positions 3 or 6, respectively. The protonated ions produced by electrospray ionization were observed by mass spectrometry and their vibrational fingerprints were recorded in the 3 μm range by IRMPD spectroscopy (InfraRed Multiple Photon Dissociation). Experimentally, the isomers show distinctive IR fingerprints. Additionally, ab initio calculations confirm the position of the O-acetylation and resolve their gas phase conformation. These findings demonstrate that the position of O-acetyl groups is retained through the transfer from solution to the gas phase, and can be identified by IRMPD spectroscopy.
Design, physico-chemical characterization andin vitrobiological activity of organogold(iii) glycoconjugates
Pettenuzzo, Andrea,Vezzù, Keti,Di Paolo, Maria Luisa,Fotopoulou, Eirini,Marchiò, Luciano,Via, Lisa Dalla,Ronconi, Luca
supporting information, p. 8963 - 8979 (2021/07/02)
To develop new metal-based glycoconjugates as potential anticancer agents, four organometallic gold(iii)-dithiocarbamato glycoconjugates of the type [AuIII(2-Bnpy)(SSC-Inp-GlcN)](PF6) (2-Bnpy: 2-benzylpyridine; Inp: isonipecotic moie
Synthetic development of sugar amino acid oligomers towards novel podophyllotoxin analogues
Bouchard, Megan,Tremblay, Thomas,Paré-Lacroix, Marie-Pier,Gagné-Boulet, Mathieu,Fortin, Sébastien,Giguère, Denis
, (2021/11/30)
In this work, we have developed an approach for the synthesis of sugar amino acid oligomers based on the glucosamine scaffold. We found that the solid-phase approach was unsuccessful for the preparation of sugar amino acid oligomers and the limitation of
Ultrasonication-Assisted Synthesis of a d-Glucosamine-Based β-CD Inclusion Complex and Its Application as an Aqueous Heterogeneous Organocatalytic System
Rani, Dhiraj,Sethi, Aaftaab,Kaur, Khushwinder,Agarwal, Jyoti
, p. 9548 - 9557 (2020/09/09)
For the first time, an inclusion complex has been crafted between a carbohydrate-based molecule and a β-cyclodextrin (CD) hydrophobic cavity for asymmetric catalytic applications. This novel d-glucosamine-based inclusion compound has been synthesized in h
Synthesis of glucosamine vinyl ether derivative and its deuterated analog
Ledovskaya, M. S.,Rodygin, K. S.,Voronin, V. V.
, p. 1401 - 1404 (2020/09/07)
The use of calcium carbide (in the presence of H2O) as a source of acetylene in the reaction with methyl 2-amino-4,6-O-benzylidene-2-deoxy-β-d-glucopyranoside under superbasic conditions (KF, KOH, DMSO, 130 °C, 3 h) led to the corresponding vin
Efficient Synthesis of Muramic and Glucuronic Acid Glycodendrimers as Dengue Virus Antagonists
García-Oliva, Cecilia,Cabanillas, Alfredo H.,Perona, Almudena,Hoyos, Pilar,Rumbero, ángel,Hernáiz, María J.
, p. 1588 - 1596 (2020/02/05)
Carbohydrates are involved in many important pathological processes, such as bacterial and viral infections, by means of carbohydrate-protein interactions. Glycoconjugates with multiple carbohydrates are involved in multivalent interactions, thus increasing their binding strengths to proteins. In this work, we report the efficient synthesis of novel muramic and glucuronic acid glycodendrimers as potential Dengue virus antagonists. Aromatic scaffolds functionalized with a terminal ethynyl groups were coupled to muramic and glucuronic acid azides by click chemistry through optimized synthetic strategies to afford the desired glycodendrimers with high yields. Surface Plasmon Resonance studies have demonstrated that the compounds reported bind efficiently to the Dengue virus envelope protein. Molecular modelling studies were carried out to simulate and explain the binding observed. These studies confirm that efficient chemical synthesis of glycodendrimers can be brought about easily offering a versatile strategy to find new active compounds against Dengue virus.
