Conformational and structural characterization of carbohydrates and their interactions studied by NMR

26 p.-9 fig.-1 tab.Carbohydrates, either free or as glycans conjugated with other biomolecules, participate in a plethora of essential biological processes. Their apparent simplicity in terms of chemical functionality hides an extraordinary diversity and structural complexi ty. Deeply deciphering at the atomic level their structures is essential to understand their biological function and activities, but it is still a challenging task in need of complemen tary approaches and no generalized procedures are available to address the study of such complex, natural glycans. The versatility of Nuclear Magnetic Resonance spectroscopy (NMR) often makes it the preferred choice to study glycans and carbohydrates in solution media. The most basic NMR parameters, namely chemical shifts, coupling constants, and nuclear Overhauser effects, allow defining short or repetitive chain sequences and charac terize their structures and local geometries either in the free state or when interacting with other biomolecules, rendering additional information on the molecular recognition pro cesses. The increased accessibility to carbohydrate molecules extensively or selectively labeled with 13C is boosting the resolution and detail which analyzed glycan structures can reach. In turn, structural information derived from NMR complemented with molecular modeling and theoretical calculations can also provide dynamic information on the con formational flexibility of carbohydrate structures. Furthermore, using partially oriented media or paramagnetic perturbations, it has been possible to introduce additional long range observables rendering structural information on longer and branched glycan chains. In this review, we provide examples of these studies and an overview of the recent and most relevant NMR applications in the glycobiology field.This study was funded by the grants from Agencia Estatal de Investigación (PID2019-1052376B-I00, CTQ2016-76263-P, RTI2018-094751-B-C22), Spanish Regional Government of Madrid (S2017/BMD-3673) and CIBERES an initiative from the Spanish Institute of Health Carlos III.Peer reviewe