Purification And Characterization Of A Novel Lectin From The Medicinal Fungus Ganoderma Applanatum In Changbai Mountain

Lectins are nonimmune origin carbohydrate-binding proteins or proteins, which arewidely distributed in animals, plants and microorganisms. In recent years, the research onlectins mainly focused on its physiological, biochemical characters and biological functions,such as defense insets in plant, gene engineering and antitumor. Modern analysis techniquehas revealed that biological activity substance is abundant in edible mushroom. Theyparticipate in and mediate life phenomena, especially immunomodulation. This study is abouta novel lectin(GAL)from medicinal fungus Ganoderma applanatum on its physiological,biochemical characters and biological functions ,which was purified by precipitation of40%-90% (NH4)2SO4, followed by ion chromatography DEAE Sephadex A-25 and HPLC.A novel lectin from the liquid cultured mycelia of medicinal fungus Ganodermaapplanatum was purified by precipitation of 40%-90% (NH4)2SO4, followed by ionchromatography DEAE Sephadex A-25 and HPLC. The purified lectin showed a single bandon SDS-PAGE. The relative molecular mass of GAL was about 58 kDa tested by HPLC, thesubunit of the lectin was about 15 kDa determined by SDS-PAGE. This implied GAL wascomposed of four subunits and it contained 11.2% carbohydrates and a high content ofglycine (35.75%), the inexistence of methionine and tryptophan. The Circular Dichroicspectra showed that it contained 3.6% α-helix, 46.8% β-turn and 49.6% random withoutβ-fold. GAL could agglutinated red blood cells, while its hemagglutinating activity fordifferent resources of red blood cells was different. In a hemagglutination assay, onlyD-Melezitose and Raffinose were the inhibitors of GAL among the sugars tested. GAL wasthermo-stable, and metal cations such as Ca2+, Mg2+ and Zn2+ had no effects on GALhemagglutinating activity. Bacteriostasis experiments implied that GAL had strong inhibitiveeffects on Escherichia colibacillus, Staphylococcus aureus and Bacillus subilis.We also tried to extract the genomic DNA from Ganoderma applanatum mycelia andclone the gene encoding the GAL by PCR. This will provide the basic information for themolecular research of GAL.We may confirm that the medicinal fungus Ganoderma applanatum contained lectin inthis study. It showed that the similar components, structure and physiological characters to thelectins from other edible mushrooms. We will study the GAL on its biological function andmolecular biology properties further.