ASSIGNMENT OF H-1 AND C-13 NUCLEAR MAGNETIC RESONANCES OF GANGLIOSIDE G(A1)

Abstract

Investigation of the structures of the gangliosides has proven to be very important in the understanding of their biological roles such as regulation of differentiation and growth of cells. We used nuclear magnetic resonance spectroscopy in order to investigate the structure of G(A1). In order to do this, the assignment of spectra is a prerequisite. Since G(A1) does not have polar sialic acid, the spectral overlap is severe. In order to solve this problem, we use 2D NMR spectroscopy and heteronuclear H-1/C-13 correlated spectroscopy in this study. Here, we report the complete assignment of the proton and the carbon spectra of the G(A1) in DMSO-d(6)-D2O (98:2, v/v). These assignments will be useful for interpreting H-1 and WC NMR data from uncharacterized oligosaccharides and for determining the linkage position, the number of sugar rings, and the sequence of new ganglioside. Amide proton in ring III shows many interring nOes and has intramolecular hydrogen bonding. This appears to be an important factor in tertiary folding of G(A1). Based on this assignment, determination of three dimensional structure of G(A1) will be carried out. Studies on the conformational properties of G(A1) may lead to a better understanding of the molecular basis of its functions.