Mucins are large glycoproteins that have been identified as the main component of various biological gels and lubricants. Their compositions contribute to the viscoelastic properties of mucus secretions. Gel-forming mucins have now been identified in a variety of organisms from marine molluscs to humans and are thought to cover and protect epithelial cells from attachment and entry of pathogens. We employed a new approach using a combination of tryptic digestion and the fractionation by hydrophobic interaction chromatography to enable the isolation and purification of mucins from the Blue Blubber jellyfish, Catostylus mosaicus. The purified proteins were stained with Alcian blue indicating extensive glycosylation. Amino acid composition analysis of the purified protein found that it was enriched for Ala, Glu, Thr, Pro and Val residues (together constituting ~93 mole % of the protein), which is typical for mucins. Consistent with this, monosaccharide composition analysis revealed extensive O-linked oligosaccharides with N-acetylgalactosamine (GalNAc), galactose (Gal) and N-acetylglucosamine (GlcNAc) as major monosaccharide constituents. The purified C. mosaicus mucins inhibited the attachment of an ocular Pseudomonas aeruginosa (PA) isolate (Paer6294) to human corneal epithelial (HCE) cells grown in vitro.
- Protein purification
- Bacterial anti-adhesion