Positive cooperativity in a (dissected) lectin-membrane glycoprotein binding event.

A transmembrane glycoprotein, glycophorin, was assembled into large liposomes that may be handled like intact cells. Under appropriate conditions, lectin binding to these simple model cells accurately mimics the positive cooperative behavior commonly reported for binding of various lectins to real cells. Hence we suggest that the simple observation of cooperativity in such a cell-surface recognition event does not necessarily imply an involvement of complex cellular machinery; rather, it may simply reflect interaction of a multivalent ligand with conformationally deformable headgroups.