Complex anionic and zwitterionic N-glycans in Drosophila melanogaster

Area of Science:

• Glycomics
• Insect Biochemistry
• Post-translational Modifications

Background:

• Drosophila melanogaster is a key invertebrate model organism.
• Understanding its N-glycome is crucial for comparative glycomics.
• Previous studies have not fully characterized its anionic N-glycans.

Purpose of the Study:

• To comprehensively analyze the anionic N-glycome of Drosophila melanogaster.
• To identify novel N-glycan structures and modifications.
• To investigate the phylogenetic relationships of Drosophila's N-glycans.

Main Methods:

• Off-line High-Performance Liquid Chromatography-Matrix-Assisted Laser Desorption/Ionization-Time of Flight-Mass Spectrometry (HPLC-MALDI-TOF-MS).
• Tandem Mass Spectrometry (MS/MS) with chemical and enzymatic treatments.
• Development of a prototype N-glycan microarray.
• Expression and activity assays for N-acetylglucosaminyltransferases II and IV.

Main Results:

• Identification of sulphated, glucuronylated, and phosphoethanolamine-modified N-glycans.
• Characterization of N-glycans with up to three antennae, LacdiNAc, and β1,3-galactosylation.
• Proposed approximately 180 N-linked oligosaccharide structures, including isomers and isobars.
• Differential lectin binding observed on a prototype microarray.
• Enzyme activities correlate with N-glycan branching.

Conclusions:

• Drosophila's N-glycome shares features with mosquitoes and honeybees, notably phosphoethanolamine modifications.
• The study provides a detailed map of Drosophila's anionic N-glycans.
• Further genomic and biochemical studies are needed to elucidate N-glycosylation biosynthesis and function in insects.