Purification, Characterization, and cDNA Cloning of a Lectin from the Mushroom Pleurocybella porrigens

A lectin, PPL, was purified from the mushroom Pleurocybella porrigens. The results of SDS-PAGE, gel filtration, and MALDI-TOF-mass of PPL indicated that its molecular mass was 56 kDa, and it was composed of four 14 kDa subunits with no disulfide bonds. In hemagglutination inhibition assay, PPL exhibited the strongest binding specificity toward GalNAc among the mono- and oligo-saccharides tested. Among the glycoproteins, asialo-bovine submaxillary mucin (asialo-BSM) showed the strongest inhibitory effect. In surface plasmon resonance analysis, asialo-BSM, porcine stomach mucin (PSM), and BSM exhibited potent binding affinity. The complete amino acid sequence was determined by amino acid sequencing of intact and of enzyme-digested PPL. The cDNA of PPL was cloned from RNA extracted from the mushroom. The open reading frame of the cDNA of the protein consisted of 411 bp, encoding 137 amino acids. This is the first report of isolation of a lectin of the genus Pleurocybella.