C.A.G.M. Weijers

Publications (5)0 Total impact

• Article: Strong inhibition of cholera toxin by multivalent GM1 derivatives

  A.V. Pukin, H.M. Branderhorst, C. Sisu, C.A.G.M. Weijers, M Gilbert, R.M.J. Liskamp, G.M. Visser, H. Zuilhof, R.J. Pieters
• Article: The Influence of Ligand Valency on Aggregation Mechanisms for Inhibiting Bacterial Toxins

  C. Sisu, A.J. Baron, H.M. Branderhorst, S. D. Connell, C.A.G.M. Weijers, Vries, E.D. Hayes, A.V. Pukin, M Gilbert, R.J. Pieters, H. Zuilhof, G.M. Visser, W.B. Turnbull
  [show abstract] [hide abstract]
  ABSTRACT: Divalent and tetravalent analogues of ganglioside GM1 are potent inhibitors of cholera toxin and Escherichia coli heat-labile toxin. However, they show little increase in inherent affinity when compared to the corresponding monovalent carbohydrate ligand. Analytical ultracentrifugation and dynamic light scattering have been used to demonstrate that the multivalent inhibitors induce protein aggregation and the formation of space-filling networks. This aggregation process appears to arise when using ligands that do not match the valency of the protein receptor. While it is generally accepted that multivalency is an effective strategy for increasing the activity of inhibitors, here we show that the valency of the inhibitor also has a dramatic effect on the kinetics of aggregation and the stability of intermediate protein complexes. Structural studies employing atomic force microscopy have revealed that a divalent inhibitor induces head-to-head dimerization of the protein toxin en route to higher aggregates
  ChemBioChem 10 (2009) 2.
• Article: Strong inhibition of cholera toxin by multivalent GM1 derivatives

  R.J. Pieters, A.V. Pukin, V. Aliaksei, H.M. Branderhorst, C.A.G.M. Weijers, M Gilbert, R.M.J. Liskamp, G.M. Visser, H. Zuilhof
• Article: Glycosyltransferase-catalyzed synthesis of bioactive oligosaccharides

  C.A.G.M. Weijers, M.C.R. Franssen, G.M. Visser
  [show abstract] [hide abstract]
  ABSTRACT: Mammalian cell surfaces are all covered with bioactive oligosaccharides which play an important role in molecular recognition events such as immune recognition, cell¿cell communication and initiation of microbial pathogenesis. Consequently, bioactive oligosaccharides have been recognized as a medicinally relevant class of biomolecules for which the interest is growing. For the preparation of complex and highly pure oligosaccharides, methods based on the application of glycosyltransferases are currently recognized as being the most effective. The present paper reviews the potential of glycosyltransferases as synthetic tools in oligosaccharide synthesis. Reaction mechanisms and selected characteristics of these enzymes are described in relation to the stereochemistry of the transfer reaction and the requirements of sugar nucleotide donors. For the application of glycosyltransferases, accepted substrate profiles are summarized and the whole-cell approach versus isolated enzyme methodology is compared. Sialyltransferase-catalyzed syntheses of gangliosides and other sialylated oligosaccharides are described in more detail in view of the prominent role of these compounds in biological recognition.
  Biotechnology Advances 26 (2008) 5.
• Article: GM3, GM2 and GM1 mimics designed for biosensing: chemoenzymatic synthesis, target affinities and 900 MHz NMR analysis

  A.V. Pukin, C.A.G.M. Weijers, Lagen, R. Wechselberger, B. Sun, M Gilbert, M.F. Karwaski, D.E.A. Florack, B C Jacobs, A P Tio-Gillen, Belkum, H P Endtz, G.M. Visser, H. Zuilhof
  [show abstract] [hide abstract]
  ABSTRACT: Undec-10-enyl, undec-10-ynyl and 11-azidoundecyl glycoside analogues corresponding to the oligosaccharides of human gangliosides GM3, GM2 and GM1 were synthesized in high yields using glycosyltransferases from Campylobacter jejuni. Due to poor water solubility of the substrates, the reactions were carried out in methanol¿water media, which for the first time were shown to be compatible with the C. jejuni ¿-(2¿3)-sialyltransferase (CST-06) and ß-(1¿4)-N-acetylgalactosaminyltransferase (CJL-30). Bioequivalence of our synthetic analogues and natural gangliosides was examined by binding to Vibrio cholerae toxin and to the B subunit of Escherichia coli heat-labile enterotoxin. This bioequivalence was confirmed by binding mouse and human monoclonal antibodies to GM1 and acute phase sera containing IgM and IgG antibodies to GM1 from patients with the immune-mediated polyneuropathy Guillain¿Barré syndrome. The synthesized compounds were analyzed by 1D and 2D 900 MHz NMR spectroscopy. TOCSY and DQF-COSY experiments in combination with 13C¿1H correlation measurements (HSQC, HMBC) were carried out for primary structural characterization, and a complete assignment of all 1H and 13C chemical shifts is presented.
  Carbohydrate Research 343 (2008) 4.