Synthesis and characterization of a novel glycopolymer with protective activity toward human anti-alpha-Gal antibodies

Carbohydrate-Based Polymers for Immune Modulation

Carbohydrates play prominent roles in immune surveillance and response to infection. Multivalency, molecular weight control, and molecular architecture control are properties that polymer science is well suited to address. Each of these properties has been demonstrated to impact the biological interaction of carbohydrate-bearing chains with their binding partners. This viewpoint highlights synthetic advances and potential applications of carbohydrate-based polymers for immune modulation. It also offers future directions in polymer science necessary for carbohydrate polymers to fulfill their potential as immune modulators.

A glycopolymer chaperone for fibroblast growth factor-2

Mono- and disaccharide-containing glycopolymers were synthesized by cyanoxyl-mediated polymerization of acrylamide with acrylate-derivatized mono- and disaccharides. We demonstrate that a glycopolymer bearing pendant, fully sulfated lactose units effectively replaces heparin and heparan sulfate as a molecular chaperone for fibroblast growth factor-2 (FGF-2). Specifically, a compound was identified that protects FGF-2 from proteolytic, acid, and heat-induced degradation, while selectively promoting growth factor and receptor dimerization. Significantly, the capacity of this heparin-mimic to promote an FGF-2 specific proliferative cell response was confirmed and suggests potential applications for this compound and related derivatives in areas related to therapeutic angiogenesis.

Galactose-substituted alginate: preliminary characterization and study of gelling properties

Coupling of alginate with 1-amino-1-deoxygalactose in the presence of 1-ethyl-3-[3-(dimethylamino)propyl]carbodiimide results in a substituted polymer containing galactose side linked via an amide bond. To clarify the degree and pattern of substitution, a (1)H NMR study on the anomeric region of modified alginate, polymannuronate, alginate enriched in guluronic acid (G-enriched alginate), and polyalternating MG, was carried out (G, alpha-l-guluronic acid; M, beta-d-mannuronic acid). From the resonance of the proton at position 1 of galactosylamine, it was possible to determine the amount of galactose linked to mannuronic and to guluronic residues, respectively. Furthermore, (1)H NMR spectroscopy revealed a higher reactivity of guluronic residues for low degrees of conversion. Modified alginates with 7% and 19% of substitution are both able to form stable beads in the presence of calcium ions. The effect of galactose substitution on the dimensions, swelling, and stability of the beads has been studied and the cytotoxicity of the modified polymer evaluated in preliminary biological tests.

Helicobacter pylori expresses an autolytic enzyme: gene identification, cloning, and theoretical protein structure

Helicobacter pylori is an important pathogen of the gastric system. The clinical outcome of infection is thought to be correlated with some genetic features of the bacterium. However, due to the extreme genetic variability of this organism, it is hard to draw definitive conclusions concerning its virulence factors. Here we describe a novel H. pylori gene which expresses an autolytic enzyme that is also capable of degrading the cell walls of both gram-positive and gram-negative bacteria. We designated this gene lys. We found this gene and observed its expression in a number of unrelated clinical strains, a fact that suggests that it is well conserved in the species. A comparison of the nucleotide sequences of lys and the hypothetical gene HP0339 from H. pylori strain ATCC 26695 revealed almost total identity, except for the presence of an insertion consisting of 24 nucleotides in the lys sequence. The coding sequences of lys and HP0339 show a high degree of homology with the coding sequence of bacteriophage T4 lysozyme. Because of this similarity, it was possible to model the three-dimensional structures of both the lys and HP0339 products.