Sensitive and Structure-Informative N-Glycosylation Analysis by MALDI-MS; Ionization, Fragmentation, and...

Area of Science:

• Biochemistry
• Analytical Chemistry
• Glycomics

Background:

• Mass spectrometry (MS) is crucial for analyzing protein post-translational modifications, particularly N-glycosylation.
• N-glycosylation analysis aims for glycoform profiling and glycosylation site mapping.
• Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) offers sensitive analysis of N-glycosylated products.

Purpose of the Study:

• To review MALDI-MS-based approaches for enhancing N-glycosylation analysis.
• To focus on techniques that overcome challenges posed by N-glycan properties.
• To improve glycoform profiling and glycosylation site mapping.

Main Methods:

• Labeling strategies to enhance glycan and glycopeptide ion yields.
• Negative-ion fragmentation for elucidating N-glycan branched structures.
• Derivatization techniques for stabilizing and discriminating sialic acid linkage isomers.

Main Results:

• Labeling significantly improves ion yields for N-glycans and glycopeptides.
• Negative-ion fragmentation provides clearer structural information on N-glycan branching.
• Derivatization aids in stabilizing and distinguishing sialic acid residues and their isomers.

Conclusions:

• MALDI-MS-based strategies, including labeling, negative-ion fragmentation, and derivatization, are effective for N-glycosylation research.
• These methods enhance sensitivity and structural elucidation capabilities in glycoform profiling and site mapping.
• The reviewed techniques address the challenges of hydrophilic and labile N-glycans for improved analytical performance.