Language

English

Date

2026.5.18（Mon）16:00~17:00 

Place

Building 3, West 2nd floor, Large Meeting Room, Yamate Campus
Exploratory Research Center on Life and Living Systems (ExCELLS)
National Institutes of Natural Sciences, Okazaki, Japan

Speaker

Prof. Göran Widmalm
Arrhenius Laboratory, Stockholm University

Title

GLYCAN STRUCTURE BY NMR

Abstract

NMR spectroscopy studies of glycans commonly utilize the spin-½ nuclei, ¹H and ¹³C, and when present ¹⁵N and ³¹P, but other nuclei such as ¹⁹F and ⁷⁷Se have also been employed in investigations of carbohydrates and their interactions with proteins. The limited spectral dispersion of oligo- and polysaccharides where most ¹H chemical shifts are found in the spectral region ~3 – 4 ppm and most ¹³C chemical shifts are found in the spectral region ~60 – 80 ppm make resonance assignments a challenging process.^1,2)

 Concatenation of NMR modules into a single 2D NMR experiment improves efficiency and results in time saving due to the fact that two or more experiments share a common recovery delay prior to each subsequent scan of the 2D NMR experiment. This concept has been extended to parallel NOAH (NMR by Ordered Acquisition using ¹H-detection) supersequences utilizing sequential, parallel and time-shared acquisitions by which ten spectra can acquired in a single measurement, referred to as a p-NOAH‑10.³⁾ A p-NOAH‑5 measurement was also tailored to produce NMR data for the computer program CASPER.^4,5)

Resonance overlap in NMR spectra of oligosaccharides can be greatly reduced, and resolution improved, by utilizing pure shift methods. Even though many correlations are resolved in ¹H,¹³C-HSQC NMR spectra some may still remain, among other things, due to ¹H,¹H couplings, though these may be refocused and the resulting pure shift ¹H,¹³C-HSQC NMR spectra are thus devoid of the homonuclear proton-proton couplings. However, peak-picking of cross-peaks in 2D NMR spectra is often time-consuming, limiting the potential of CASPER as an efficient analysis tool. Since pure shift methods aim to collapse multiplets into well-resolved singlets, pure shift data are ideal for use in conjunction with CASPER, allowing for efficient analysis by using automated peak-picking routines.⁶⁾ Further refinement of ¹H NMR chemical shifts and nJHH may be carried out by spin-simulation resulting in data useful for conformational analysis of the glycans.

1. C. Fontana, G. Widmalm, Chem. Rev. 2023, 123, 1040-1102.
2. G. Widmalm, JACS Au 2024, 4, 20-39.
3. Ē. Kupče, J.R.J. Yong, G. Widmalm, T.D.W. Claridge, JACS Au 2021, 1, 1892-1897.
4. M. Lundborg, G. Widmalm, Anal. Chem. 2011, 83, 1514-1517.
5. K. M. Dorst, G. Widmalm, Methods Mol. Biol. 2025, 2961, 23-38.
6. M. J. Smith, E. L. Gates, G. Widmalm, R. W. Adams, G. A. Morris, M. Nilsson, Org. Biomol. Chem. 2023, 　21, 3984-3990.

Poster

Contact

Biomolecular Organization Research Group
KATO, Koichi