Abstract
A general property of the high-resolution proton NMR spectra of oligosaccharides is the appearance of low-field well-resolved resonances corresponding to the anomeric (H1) and H2 protons. The remaining skeletal protons resonate in the region 3-4 ppm, giving rise to an envelope of poorly resolved resonances. Assignments can be made from the H1 and H2 protons to their J-coupled neighbors (H2 and H3) within this main envelope by using 1H-1H correlated spectroscopy. However, the tight coupling (J congruent to delta) between further protons results in poor spectral dispersion with consequent assignment ambiguities. We describe here three-step two-dimensional relayed correlation spectroscopy and show how it can be used to correlate the resolved anomeric (H1) and H2 protons with remote (H4, H5) protons directly through a linear network of couplings using sequential magnetization transfer around the oligosaccharide rings. Resonance assignments are then obtained by inspection of cross-peaks that appear in well-resolved regions of the two-dimensional spectrum. This offers a general solution to the assignment problem in oligosaccharides and, importantly, these assignments will subsequently allow for the three-dimensional solution conformation to be determined by using one-dimensional and two-dimensional nuclear Overhauser experiments.
Full text
PDF
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Brisson J. R., Carver J. P. Solution conformation of asparagine-linked oligosaccharides: alpha(1-2)-, alpha(1-3)-, beta(1-2)-, and beta(1-4)-linked units. Biochemistry. 1983 Jul 19;22(15):3671–3680. doi: 10.1021/bi00284a021. [DOI] [PubMed] [Google Scholar]
- Brisson J. R., Carver J. P. Solution conformation of asparagine-linked oligosaccharides: alpha(1-6)-linked moiety. Biochemistry. 1983 Jul 19;22(15):3680–3686. doi: 10.1021/bi00284a022. [DOI] [PubMed] [Google Scholar]
- Dorland L., Haverkamp J., Schut B. L., Vliegenthart J. F. The structure of the asialo-carbohydrate units of human serotransferrin as proven by 360 MHz proton magnetic resonance spectroscopy. FEBS Lett. 1977 May 1;77(1):15–20. doi: 10.1016/0014-5793(77)80183-x. [DOI] [PubMed] [Google Scholar]
- Homans S. W., Dwek R. A., Fernandes D. L., Rademacher T. W. Solution conformation of the biantennary N-linked oligosaccharide of human serotransferrin using 1H NMR nuclear Overhauser effect measurements. FEBS Lett. 1982 Dec 27;150(2):503–506. doi: 10.1016/0014-5793(82)80799-0. [DOI] [PubMed] [Google Scholar]
- Homans S. W., Dwek R. A., Fernandes D. L., Rademacher T. W. The analysis of coupling networks in a complex oligosaccharide mixture derived from the Fc region of rabbit immunoglobulin G using 1H-1H correlated NMR spectroscopy combined with double quantum NMR spectroscopy. Biochim Biophys Acta. 1984 Mar 22;798(1):78–83. doi: 10.1016/0304-4165(84)90012-6. [DOI] [PubMed] [Google Scholar]
- Homans S. W., Dwek R. A., Fernandes D. L., Rademacher T. W. The use of two-dimensional correlated spectroscopy to obtain new assignments in the high-resolution 1H nuclear magnetic resonance spectrum of the biantennary complex oligosaccharide isolated from human serum transferrin by hydrazinolysis. Biochim Biophys Acta. 1983 Oct 18;760(2):256–261. doi: 10.1016/0304-4165(83)90171-x. [DOI] [PubMed] [Google Scholar]
- Yamashita K., Kamerling J. P., Kobata A. Structural study of the carbohydrate moiety of hen ovomucoid. Occurrence of a series of pentaantennary complex-type asparagine-linked sugar chains. J Biol Chem. 1982 Nov 10;257(21):12809–12814. [PubMed] [Google Scholar]