A FTIR spectroscopy evidence of the interactions between wheat germ agglutinin and N-acetylglucosamine residues.

Wheat germ agglutinin (WGA), a lectin binding a N-acetyl-D-neuraminic acid (NeuNAc) and/or N-acetyl-D-glucosamine (GlcNAc) group, was studied by Fourier transform infrared (FTIR) spectroscopy. Deconvolution of the FTIR spectrum of WGA alone indicated the presence of few alpha-helices and beta-sheets, in contrast to many other lectins. These results agree with previous WGA crystal data. The WGA conformational changes, induced by GlcNAc-bearing liposomes or GlcNAc oligomers, were studied by infrared differential spectroscopy. The GlcNAc binding to WGA resulted in a decrease of turns and alpha-helices and a concomitant appearance of beta-sheets, inducing more or less peptidic N-H deuteration.