Analysis of glycoproteins for biomarker discovery

Lectin from Canavalia villosa seeds: A glucose/mannose-specific protein and a new tool for inflammation studies

With important carbohydrate binding properties, lectins are proteins able to decipher the glycocode, and as such, they can be used in bioassays involving cell-cell communication, protein targeting, inflammation, and hypernociception, among others. In this study, a new glucose/mannose-specific lectin from Canavalia villosa seeds (Cvill) was isolated by a single affinity chromatography step in a Sephadex^® G-50 column, with a purification yield of 19.35mg of lectin per gram of powdered seed. Analysis of intact protein by mass spectrometry showed the lectin is composed of three polypeptide chains, including a 25.6kDa α chain, 12.9KDa β, and 12.6 KDa γ fragments, similar to the profile of ConA-like glucose/mannose-specific lectins. Partial sequence of the protein was obtained by MS-MALDI TOF/TOF covering 41.7% of its primary structure. Cvill presented sugar specificity to d-glucose, α-methyl-d-mannoside, d-mannose, and glycoproteins fetuin and ovoalbumin. The lectin characterization showed that Cvill presents high stability within a broad range of pH and temperature, also showing average toxicity against Artemia nauplii. The proinflammatory effect of Cvill was observed by induction of paw edema and hypernociception in mice, with the participation of the carbohydrate binding site, showing its potential to be used as tool in inflammation studies.