Showing papers by "Pavla Bojarová published in 2017"
TL;DR: In this article, a set of tailored multivalent neo-glycoproteins and evaluate their Gal-3 binding properties were synthesized by combinatorial use of glycosyltransferases and chemo-enzymatic reactions.
52 citations
TL;DR: It is concluded that the use of the (β1,4GlcNAc)n=0-3 spacer is a perfect nature-like solution for the presentation of elaborated Gal-3 glycan epitopes that surpasses the performance of commonly used synthetic spacers.
Abstract: A two-step synthesis of engineered variants of Talaromyces flavus β-N-acetylhexosaminidase (TfHexY470N) and human β4-galactosyltransferase (β4GalTY284L) yielded complex glycans comprising a chitooligomeric spacer (β1,4GlcNAc)n=0-3 terminated with a β4-linked β-D-GalNAc-(1→4)-D-GlcNAc (LacdiNAc) epitope. These compounds are novel inhibitors of human galectin 3 (Gal 3), a widely spread animal lectin with important physiological functions in cellular communication. The multivalent presentation of glycan oligomers was accomplished by chemical conjugation of glycans to lysine residues of bovine serum albumin (BSA). Binding studies of Gal-3 to immobilized BSA neo-glycoconjugates revealed the beneficial influence of the chitooligomeric spacer for the ligand-lectin affinity. We conclude that the use of the (β1,4GlcNAc)n=0-3 spacer is a perfect nature-like solution for the presentation of elaborated Gal-3 glycan epitopes that surpasses the performance of commonly used synthetic spacers.
30 citations
TL;DR: This study presents the first HPMA copolymers derivatized with long oligosaccharides that demonstrate high affinity to a lectin target, and the binding affinities in the low nanomolar and subnanomolar ranges place the prepared glycopolymers among the best WGA ligands reported to date.
29 citations
TL;DR: Engineering of N-acetylhexosamine-active enzymes was able to solve complex issues such as synthesis of tailored human-like glycoproteins or industrial-scale production of desired oligosaccharides, and a good understanding of its details opens new possibilities in this fast developing area of glycoscience.
25 citations
TL;DR: The herein synthesized branched LacNAc oligomers feature a variation of Lac(di)NAc epitopes and were confirmed to be potent inhibitors of human galectin 3 (Gal-3) and ranks among the most potent poly-LacNAc-based Gal-3 inhibitors so far.
Abstract: We present here a novel concept for the synthesis of branched N-acetyllactosamine (LacNAc) glycan structures. Through a combination of sequential enzymatic and chemical reactions of Leloir-glycosyltransferases, galactose oxidase and reductive amination, we obtained branched glycan oligomers with a variation of LacNAc and/or N’,N’’-diacetyllactosamine (LacdiNAc) glycan epitopes. Incorporation of a branching point was accomplished by an optimized galactose oxidase protocol rendering the C-6 aldehyde functionality at the terminal galactose of a LacNAc oligomer. After glycan chain elongation by glycosyltransferases, the C-6 aldehyde containing linear building block was conjugated with amine-linker functionalized glycans. Methanol and a temperature of 50 °C were found to be optimum conditions for the α-picoline borane catalyzed reductive amination. Chemically branched glycans were obtained in high synthetic yields (~81 %) in preparative batches. Product isolation was accomplished by preparative HPLC with good overall yields (>60 %). The structural integrity was proven by ESI-MS and NMR. The herein synthesized branched LacNAc oligomers feature a variation of Lac(di)NAc epitopes and were confirmed to be potent inhibitors of human galectin 3 (Gal-3). The branched decasaccharide with two LacdiNAc-LacNAc branches ranks among the most potent poly-LacNAc-based Gal-3 inhibitors so far.
10 citations