Carbohydrate Structural Determination by NMR Spectroscopy:  Modern Methods and Limitations

Abstract

I. Introduction and Scope 4589 II. NMR Methods for Structural Determination 4591 A. Carbohydrate Structural Elements and Classical NMR Methods 4591 1. Number of Sugar Residues 4592 2. Constituent Monosaccharides 4592 3. Anomeric Configuration 4593 4. Linkage and Sequence 4594 5. Position of Appended Groups 4594 6. Classical NMR Methods 4594 B. New NMR Methods 4596 C. Computer-Assisted Structural Analysis 4598 D. NMR Spectroscopy of Mixtures 4599 III. Large and Unusual Oligosaccharides 4600 IV. Polysaccharides 4603 V. NMR Analysis of Small Sample Amounts 4604 A. NMR Probes and Sample Tubes 4605 B. Examples of Structural Analysis with Small Sample Amounts 4606 VI. Conclusions 4610 VII. Acknowledgments 4610 VIII. References 4610 † This paper is dedicated to the late Professor R. U. Lemieux in memory of an always exiting and stimulating collaboration on structural studies of oligosaccharides.Jens Ø. Duus received his M.Sc. degree in Chemical Engineering from the Technical University of Denmark in 1989. Following this, he continued his graduate study with Professor Klaus Bock at the Carlsberg Laboratory and was granted his Ph.D. degree from the Technical University of Denmark in 1993. During his graduate study he was twice a Visiting Scientist at Dupont Experimental Station in Wilmington, DE working with Dr. S. Sabesan. From 1993 to 1994 he was a Research Fellow in Chemistry at the Beckman Institute at the California Institute of Technology working with Professor Harry B. Gray. After returning to the Carlsberg Laboratory, he was appointed Senior Scientist. His main fields of research are structure and dynamics of biomolecules with emphasis on carbohydrates using NMR and fluroescence.

Evaporative fluorophore labeling of carbohydrates via reductive amination

“…Glycosylation is one of the major and most complicated forms of post-translational modifications that plays essential roles in the activity and effector function of monoclonal antibodies [3] demanding improved glycoanalytical methods. Frequently 3/13 used techniques for carbohydrate analysis are mass spectrometry (MS) [4], liquid chromatography (LC) [5,6], capillary electrophoresis (CE) [7][8][9], some combination of them [10][11][12] and if necessary, nuclear magnetic resonance spectroscopy (NMR) [13,14].…”

Biosynthesis, Purification and Biotechnological Use of Exopolysaccharides Produced by Lactic Acid Bacteria

“…Nuclear magnetic resonance (NMR) is the technique most often used to study the conformation of the polysaccharides and allows elucidation of the type of glycosidic linkages and the structure of the repeating units that constitute the EPS molecules (review by Duus et al, 2000). Before NMR analysis, the purified EPS is dissolved in D 2 O so that exchangeable protons are replaced by deuterium (deuteration).…”

Anomeric Effect in Carbohydrates: Facts and Hypothesis

“…Tal valor médio é obtido a partir dos valores individuais da propriedade para cada confôrmero, podendo tais valores inclusive diferir bastante entre si. Diferentemente de um dado experimental para uma estrutura rígida (onde desvios em relação à média são frequentemente pouco significativos), qualquer medida experimental para a glicose em solução aquosa (por exemplo, dados de ressonância magnética nuclear como deslocamentos químicos ou constantes de acoplamento de spin, ou ainda valores de rotação ótica) é um dado médio de confôrmeros com desvios significativos em relação à média 6 e portanto vale lembrar que qualquer parametrização que use dados experimentais diretamente na inferência de dados geométricos de carboidratos, sem levar em conta sua decomposição nas contribuições conformacionais individuais, pode levar a grandes equívocos estruturais.…”