Isolation and partial characterization of a small chitin-binding lectin from mistletoe (Viscum album).

A novel lectin, called VisalbCBA, was isolated from European mistletoe (Viscum album). This lectin differs completely from the classical galactose/N-acetylgalactosamine-binding mistletoe lectins MLI, MLII and MLIII. Biochemical analyses indicated that VisalbCBA is a dimeric protein composed of two identical subunits of approx. 10 kDa. VisalbCBA exhibits specificity towards oligomers of N-acetylglucosamine and shows sequence homology to the previously isolated chitin-binding plant proteins. Although VisalbCBA is less toxic than the other mistletoe lectins, it definitely exhibits cytotoxic properties. The possible involvement of VisalbCBA in the biological and therapeutic effects of mistletoe is discussed.