Structural studies on antineoplastic lectins of edible mushrooms

BOVI, MICHELE; CARRIZO, MARÍA E.; CAPALDI, STEFANO; PERDUCA, MASSIMILIANO; AMBROSI, EMMANUELE; MONACO, HUGO L.

Como, Italia

Congreso; 8th International School on the Crystallography of Biological Macromolecules; 2006

A new lectin was isolated from the fruiting bodies of the edible mushroom Boletus edulis by affinity chromatography on a chitin column. Boletus edulis lectin had a mass of approximately 15 kDa in SDS-PAGE under reducing condition and exhibited several basic isoforms in isoelectric focusing gel. The BEL primary sequence, obtained by cloning its cDNA, was composed by 142 amino acids and showed a high similarity with the members of the fungal saline-soluble lectin family. The studies of the binding properties of the lectin showed that, as for Agaricus bisporus lectin (ABL)1, BEL has two different binding sites. One with specifity for Thomsen Friedenreich antigen (TF antigen, Galβ1-3GalNAcα-O-Ser/Thr), the other with specifity for N-Acetyl-Glucosammine. The crystals belong to space group P6122 (n°178), with unit-cell parameters a = b = 122.93, c = 103.15 Å. The apo form diffracts to1.82 Å with Rsym of 5.61%, co-crystal with the two different ligands diffracts to 2.30 Å with Rsym of 11.32%. Interactions studies between lectin and some human tumor cells showed that BEL exhibited a potent dose-dependent antiproliferative activity with no apparent cytotoxicity. 1. Carrizo, M.E., Capaldi, S., Perduca, M., Irazoqui, F.J., Nores, G.A., & Monaco, H.L. (2005) J. Biol. Chem. 280, 10614-10623.