Carbohydrate binding properties of banana (Musa acuminata) lectin - II. Binding of laminaribiose oligosaccharides and beta-glucans containing beta 1,6-glucosyl end groups

This paper extends our knowledge of the rather bizarre carbohydrate binding poperties of the banana lectin (Musa acuminata). Although a glucose/mannos e binding protein which recognizes alpha -linked gluco-and manno-pyranosyl groups of polysaccharide chain ends, the banana lectin was shown to bind to internal 3-O-alpha -D-glucopyranosyl units. Now we report that this lectin also binds to the reducing glucosyl groups of beta -1,3-linked glucosyl ol igosaccharides (e.g. laminaribiose oligomers). Additionally, banana lectin also recognizes beta1,6-linked glucosyl end groups (gentiobiosyl groups) as occur in many fungal beta1,3/1,6-linked polysaccharides. This behavior cle arly distinguishes the banana lectin from other mannose/glucose binding lec tins, such as concanavalin A and the pea, lentil and Calystegia sepium lect ins.