Purification and structural characterization of lectin with antibacterial and anticancer properties from grubs of hide beetle, Dermestes frischii.

Lectins or haemagglutinins are diverse classes of non-immune proteins; they bind to carbohydrates and are abundant in nature. In the present study, a coleopteran lectin from grubs of hide beetle, Dermestes frischii called DFL, was purified by glutaraldehyde (fixative-agent) fixed hen erythrocytes and characterized further for its functional properties. The purified DFL was stable between pH range 5 to 9 and heat-stable up to 50 °C. It was insensitive to EDTA and did not require any divalent cations. DFL native molecular mass was approximately 69 kDa with three different polypeptide subunits of 33 (pI ~4.4), 22 (pI ~6) and 14 (pI ~4.4) kDa. Haemagglutinating activity of DFL was highly inhibited by N-acetyl-D-glucosamine. DFL partial peptide sequences obtained from peptide mass fingerprinting experiments matched with amino acid sequences of lectins from different organisms confirmed its nature. Biological properties of purified DFL namely antibacterial and bacterial agglutination experiments revealed that DFL have both the effects against laboratory cultures of Aeromonas hydrophila, Enterococcus faecalis, Escherichia coli and habitat bacterial isolates of Staphylococcus cohnii and Bacillus cereus. In addition, the DFL exhibited substantial anticancer properties against HeLa cells. These results concluded that purified DFL could serve as a potent therapeutic agent for various biomedical applications.

Isolation, characterization of galactose-specific lectin from Odoiporus longicollis and its antibacterial and anticancer activities.

Lectins are renowned hemagglutinins and multivalent proteins with a well known quality for sugar-binding specificity that participate significantly in invertebrate defense functions. Studies on biological activity of lectin from coleopteran insect are very scarce. In this study, lectin from the hemolymph in the grub of banana pest, Odoiporus longicollis was subjected to purification, biochemical and functional characterizations. The lectin was purified by PEG precipitation and ion-exchange chromatography using Q-Sepharose as a matrix. The purified lectin showed hemagglutination activity against rat erythrocytes, heat-labile, cation independent and insensitive to EDTA. Further, the carbohydrate affinity of this lectin was found with mannitol, adonitol, L-arabinose, L-rhamnose, D-galactose and sorbitol. The native form of purified lectin was calculated as 360 kDa by FPLC system. Denatured gel electrophoresis of the purified lectin consisted of five distinct polypeptides with molecular weights approximately 160, 60, 52, 40 and 38 kDa, respectively. The amino acid sequences obtained through peptide mass fingerprinting analysis exhibited homologies to the known conserved regions of galactose binding lectins. Further, the purified lectin exhibited bacterial inhibition with LPS from Serratia marcescens. In addition, isolated lectin also exerted bacterial agglutination, antibacterial and anti-proliferative activity against Mycobacterium smegmatis, Bacillus pumilus and Neuro 2a cell line, respectively.