RESUMO
An antifungal protein (HM-af) was purified from the culinary-medicinal mushroom Hypsizygus marmoreus. The results of sodium dodecyl sulfate polyacrylamide gel electrophoresis and matrix-assisted laser desorption ionization time-of-flight mass spectrometry of HM-af indicated that its molecular mass was 9.5 kDa. The N-terminal amino acid sequence of HM-af showed homology to ribonuclease H from Clostridium thermocellum. HM-af showed the antifungal activity against Flammulina velutipes.
Assuntos
Agaricales/química , Antifúngicos/farmacologia , Misturas Complexas/farmacologia , Flammulina/efeitos dos fármacos , Proteínas Fúngicas/farmacologia , Sequência de Aminoácidos , Antifúngicos/química , Antifúngicos/isolamento & purificação , Bioensaio , Misturas Complexas/química , Misturas Complexas/isolamento & purificação , Eletroforese em Gel de Poliacrilamida , Flammulina/crescimento & desenvolvimento , Carpóforos/química , Proteínas Fúngicas/química , Proteínas Fúngicas/isolamento & purificação , Peso Molecular , Mapeamento de Peptídeos , Ribonuclease H/química , Homologia de Sequência de Aminoácidos , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por MatrizRESUMO
A carbohydrate-binding protein was isolated from the carpophores of the mushrooms and designated the Chlorophyllum molybdites lectin (CML) based on its origin. The molecular mass of CML was 32 kDa, and it was composed of two 16-kDa monomers with no disulfide bonds. Monosaccharide analysis indicated that 12% of the mass of CML was carbohydrate and consisted of GlcNAc:GalNAc:Gal:Man:l-Fuc in a molar ratio of 1.5:1.9: 4.4:4.8:1.0. In the hemagglutination inhibition assay, CML exhibited the strongest binding specificity toward N-glycolylneuraminic acid (NeuGc) among the monosaccharides tested, whereas NeuAc did not inhibit the hemagglutination at all. GalNAc and Mealpha-GalNAc were also inhibitory at much higher concentrations than NeuGc. Among the glycoproteins, asialobovine submaxillary mucin (BSM) and porcine stomach mucin (PSM) showed strong inhibitory effects. In surface plasmon resonance analysis, asialo-BSM and PSM exhibited the strongest binding affinity. After co-injection of CML and NeuGc or GalNAc onto the asialo-BSM- or PSM-immobilized chip, the dissociation of CML from the immobilized PSM was accelerated by NeuGc and GalNAc, but the dissociation of CML from the immobilized asialo-BSM was only promoted by GalNAc. These results and the other surface plasmon resonance experiments allowed us to conclude that the binding of asialo-BSM to CML was because of an interaction between the lectin and the GalNAc residues of asialo-BSM, and both the NeuGc and GalNAc residues were responsible for the binding of PSM to CML. The results also suggested that CML had two different carbohydrate binding domains, one specific for NeuGc and the other for GalNAc.