Sialic acid C-glycosides with aromatic residues: investigating enzyme binding and inhibition of Trypanosoma cruzi trans-sialidase.

Several α-configured C-sialosides were synthesised by cross metathesis and further synthetic derivatisation to obtain ligands for Trypanosoma cruzi trans-sialidase (TcTS), a key enzyme in Chagas disease. Affinities of these compounds to immobilised TcTS were measured by surface plasmon resonance (SPR). The K(D) values thus obtained are in the lower millimolar range and will be discussed.

Enzymatic glycosylation, inhibitor design, and synthesis and formation of glyco-self assembled monolayers for simulation of recognition.

Glycosyltransferases from the albumen gland of Helix pomatia could be used in tandem mode for the chemoenzymatic synthesis of beta,1-3/beta,1-6-linked oligogalactans. By employing recombinant trans-sialidase of Trypanosoma cruzi (TcTS) the formation of a range of modified Galbeta,1-3GalNAc derivatives could be terminally alpha,2-3 sialylated. Biacore studies indicated the binding of these modified trisaccharides to myelin-associated glycoprotein (MAG).

Transsialidase from Trypanosoma cruzi for regio- and stereoselective synthesis of N-acyl-modified sialylated oligosaccharides and measurement of transfer rates.

Recombinant transsialidase from Trypanosoma cruzi (TcTS) was used for the sialylation with natural and non-natural derivatives of neuraminic acid. Neu5Ac-alpha(2-->3)-Gal-beta(1-->6)-Glc-alphaOMe was prepared in 80 % yield. Correspondingly, the modified trisaccharide derivatives Neu5Prop-alpha(2-->3)-Gal-beta(1-->6)-Glc-alphaOMe (32 %) and Neu5Gc-alpha(2-->3)-Gal-beta(1-->6)-Glc-alphaOMe (Prop=propanoyl, Gc=glycolyl) were obtained in 60 % yield, respectively.