Plant and Insect Glycan Analysis

Unless genetically engineered, plant N-glycans can be oligomannose, complex, hybrid and paucimannose with the N-glycans often modified at the core b-mannose with a b1-2 xylose residue. Additionally, the GlcNAc core of the N-glycan can be modified by an a1-3 fucose (Fig. 1). This core modification:

• Is known to be allergenic in humans
• Makes N-glycans resistant to PNGase F cleavage
• Can be cleaved by PNGase A and Endo D

Generally, insect N-glycans tend to be either high-mannose or paucimannose structures and unless genetically engineered the N-glycans also can be modified at the GlcNAc core by an a1-3 fucose (Fig. 1).

Figure 1: Typical N-glycan structures produced in plant and insects.

FAQs:

1. What is the difference between PNGase F and PNGase A?
2. Can PNGase A be used under non-denaturing (native) conditions?
3. Which high mannose structures can PNGase A cleave?
4. Can PNGase A cleave large, complex oligosaccharides?
5. What happens to the asparagine after PNGase A removes the sugar?
6. What is a good PNGase A substrate?
7. Is PNGase A compatible with downstream analysis such as HPLC and Mass Spectrometry?