Structural and functional characterization of mannose binding lectins from selected plants

Abstract

Lectins are the proteins/glycoproteins having at least one non-catalytic domain which plays major role in reversible binding of specific monosaccharides or oligosaccharides. In the mannose binding lectins, conserved motif QXDXNXVXY decides the number of mannose binding sites in the polypeptide chain. In our present work, two Mannose binding plant lectins, ASA (Allium sativum agglutinin) from garlic (Allium sativum) bulbs and GRLEC (Ginger rhizome lectin) from ginger (Zingiber officinale) rhizome have been isolated and purified using different chromatographic techniques. Hemagglutination activity and hemagglutination inhibition studies were done using rabbit erythrocytes. Thermal stability and secondary structure of the lectins were predicted using fluorescence and CD spectroscopy. Anti-cancer activity of the proteins was analysed through MTT, FACS and DAPI staining. A strong anti-cancer effect of ASA and GRLEC was observed against cervical cancer (HeLa) cell with IC50 of 37 and#956;g/ml and 26 and#956;g/ml respectively after 24 hours of treatment. Anti-bacterial potential (effect on biofilm) of both the lectins was analysed on three bacterial strains. Anti-fungal activity of ASA was analysed against Candida auris and Candida glabrata fungal strains. Different experiments such as DAB staining, CSH estimation and microscopic observation (FE-SEM) were performed for investigation of antifungal effect of ASA. Bioinformatics analysis of bulb type lectins was done using different bioinformatics tools. Crystallization experiment of purified proteins were set up using different precipitant and buffer conditions. Another cloned protein ACA (Allium cepa agglutinin) was tried for expression and purification. newline