Marine-Chondroitin-Sulfate-Backbone-Branches-Acid-v

FucCS exhibits potential biological actions including inhibition of blood clotting and severe acute respiratory syndrome coronavirus structural features, including molecular weight (MW), andor those related to fucosylation, such as degrees of fucosyl branches, sulfation patterns and contents. In a previous work, we were able to generate oligosaccharides of the FucCS from Pentacta pygmaea (PpFucCS) with reduced anticoagulant effect but still retaining significant anti-SARS-CoV-2 activity against the delta strain. In this work, we extended our study to the FucCS extracted from the species Holothuria floridana (HfFucCS). The oligosaccharides were prepared by free-radical depolymerization of the HfFucCS via copper-based Fenton reaction. One-dimensional 1H nuclear magnetic resonance spectra were employed in structural analysis. Activated partial thromboplastin time and assays using protease (factors Xa and IIa) and serine protease inhibitors (antithrombin, and heparin cofactor II) in the presence of the sulfated carbohydrates were used to monitor anticoagulation.

Anti-SARS-CoV-2 effects were measured using the concentration-response inhibitory curves of HEK-293T-human angiotensin-converting enzyme-2 cells infected with a baculovirus pseudotyped SARS-CoV-2 wild-type and delta variant spike (S)-proteins. Furthermore, the cytotoxicity of native HfFucCS and its oligosaccharides was also assessed. Like for PpFucCS, we were able to generate a HfFucCS oligosaccharide fraction devoid of high anticoagulant effect but still retaining considerable anti-SARS-CoV-2 actions against both variants. However, compared to the oligosaccharide fraction derived from PpFucCS, the average MW of the shortest active HfFucCS oligosaccharide fraction was significantly lower. 2'-fucosyllactose suggests that the specific structural feature in HfFucCS, the branching 3,4-di-sulfated fucoses together with the backbone 4,6-di-sulfated N-acetylgalactosamines, is relevant for the anti-SARS-CoV-2 activity of FucCS molecules.the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Conflict of interest statement The authors declare no conflict of interest.

The Thermodynamics of oligosaccharide binding to a monoclonal antibody specific for a Salmonella O-antigen point to hydrophobic interactions in the binding site.The thermodynamic characteristics of oligosaccharide binding to an antibody binding site that is dominated by aromatic amino acids suggest that the hydrophobic effect contributes substantially to complex formation as well as hydrogen bonding and van der Waals interactions. A detailed titration microcalorimetric study on the temperature dependence of the binding of a trisaccharide, representing the epitope of a Salmonella O-antigen, showed that its maximum binding to the monoclonal antibody Se155-4 occurs just below room temperature and both enthalpy and entropy changes are strongly dependent on temperature in a mutually compensating manner. The heat capacity change also shows an unusually strong temperature dependence being large and negative above room temperature and positive below. van't Hoff analysis of the temperature dependence of the binding constant yielded a biphasic curve with two apparent intrinsic enthalpy estimations (approximately -0 kJ mol-1 above 18 degrees C and approximately +0 kJ mol-1 below), each very different from the calorimetrically determined enthalpies (ranging from about - kJ mol-1 to - kJ mol-1). This was interpreted as being due to large enthalpy contributions from concomitant reactions, most notably changes in solvation. 2'-fucosyllactose , -delta versus -T delta , observed for temperature-dependent measurements mirror the behavior seen for a series of functional group replacements, suggesting that the molecular and physical origin of these phenomena are closely related and linked to the role of water in complex formation.

The thermodynamic results are compared to the mode of binding determined from a 25-A resolution structure of the Fab-oligosaccharide complex, and with literature data for the heat capacities of sugars in aqueous solution and for the thermodynamics of carbohydrate binding to transport proteins and lectins.Separation and characterization of underivatized oligosaccharides using liquid chromatography and liquid chromatography-electrospray ionization mass Native cyclodextrin-based columns are particularly useful for the analysis of oligosaccharides because the retention of these carbohydrates is based mainly on the hydrogen bonding interactions of oligosaccharide hydroxyl groups with the stationary phase.