Linkage Memory in Underivatized Protonated Carbohydrates

Area of Science:

• Biochemistry
• Analytical Chemistry
• Structural Biology

Background:

• Carbohydrates are complex biomolecules with diverse functions, yet their structural analysis presents challenges.
• Mass spectrometry is crucial for glycomics and glycoproteomics but struggles with carbohydrate gas-phase structures and fragmentation.
• Understanding carbohydrate structure is vital for deciphering their biological roles.

Purpose of the Study:

• To investigate the gas-phase properties of isomeric protonated disaccharides with varying linkage configurations.
• To explore how linkage variations influence fragmentation patterns and ion mobility.
• To determine if fragment ions retain information about the intact carbohydrate structure.

Main Methods:

• Tandem mass spectrometry to analyze fragment ion abundances.
• Ion mobility measurements in various gases to assess conformational differences.
• Gas-phase hydrogen-deuterium exchange to study deuterium uptake kinetics.

Main Results:

• Multiple conformations were identified for most disaccharide isomers.
• Fragment ion abundances and ion mobility varied characteristically with linkage configuration.
• Y-ion fragments demonstrated a distinct influence from the precursor carbohydrate's linkage.

Conclusions:

• Protonated carbohydrate fragment ions can retain "linkage memory" from their precursor.
• This linkage memory provides valuable structural insights into intact carbohydrates.
• The findings advance mass spectrometry-based carbohydrate structural elucidation.