Mass Spectrometry-Based Techniques to Elucidate the Sugar Code

Abstract

Cells encode information in the sequence of biopolymers, such as nucleic acids, proteins, and glycans. Although glycans are essential to all living organisms, surprisingly little is known about the “sugar code” and the biological roles of these molecules. The reason glycobiology lags behind its counterparts dealing with nucleic acids and proteins lies in the complexity of carbohydrate structures, which renders their analysis extremely challenging. Building blocks that may differ only in the configuration of a single stereocenter, combined with the vast possibilities to connect monosaccharide units, lead to an immense variety of isomers, which poses a formidable challenge to conventional mass spectrometry. In recent years, however, a combination of innovative ion activation methods, commercialization of ion mobility–mass spectrometry, progress in gas-phase ion spectroscopy, and advances in computational chemistry have led to a revolution in mass spectrometry-based glycan analysis. The present review focuses on the above techniques that expanded the traditional glycomics toolkit and provided spectacular insight into the structure of these fascinating biomolecules. To emphasize the specific challenges associated with them, major classes of mammalian glycans are discussed in separate sections. By doing so, we aim to put the spotlight on the most important element of glycobiology: the glycans themselves.

Bridging the Chemical Profiles and Biological Effects of Spathodea campanulata Extracts: A New Contribution on the Road from Natural Treasure to Pharmacy Shelves

“…With regard to flavonols, a number of quercetin and kaempferol- O -glycosides were identified predominantly in the leaves of S. campanulata . The type of the sugar unit (hexoside or pentoside) was deduced from the difference in the mass of the deprotonated molecular ion and the masses of the corresponding product ions detected in the MS/MS spectra [ 35 ]. In addition to quercetin ( 50 ), isoquercetin ( 26 ), and quercetin- O -dihexoside ( 41 ), found only in the methanolic leaf extract, a number of quercetin conjugates were characterized in both leaf extracts [ 36 ].…”

Dextran as internal calibrant for N-glycan analysis by liquid chromatography coupled to ion mobility-mass spectrometry

“…[ 33 ]. Most of the state-of-the-art IMS instruments, however, utilize non-homogeneous electric fields which preclude the determination of absolute CCSs (e.g., TWIMS, TIMS) [ 8 ]. To enable the estimation of CCSs, these IMS instruments require careful calibration with a suitable standard.…”

“…The characterization of N -glycans usually requires the cleavage of the glycans from the protein and a subsequent reducing end modification with a fluorescent label [ 6 , 7 ]. The following analysis is often based on liquid chromatography (LC) in combination with fluorescence (FLD) or mass spectrometry (MS) detection [ 8 , 9 ]. Although fluorescent labeling is not necessary for MS detection, many labels offer improved ionization properties (such as procainamide in positive ion mode) and therefore represent a popular choice to simplify MS analysis [ 10 ].…”

A Species-Specific Strategy for the Identification of Hemocoagulase Agkistrodon halys pallas Based on LC-MS/MS-MRM

“…Mass spectrometry plays a key role in the structural characterization of glycans, proteins, glycan–protein interactions, and protein–protein interactions ( Britt et al, 2022 ; Grabarics et al, 2022 ; Sheng et al, 2021 ; Zhang and Chi, 2021 ). Shotgun proteomics based on liquid chromatography−tandem mass spectrometry (LC−MS/MS) and database search are widely used for the qualitative and quantitative analysis of proteins in complex biological samples ( Huang and Wang, 2021 ; Marques et al, 2021 ).…”