Sambucus ribosome-inactivating proteins and lectins

Abstract

Plant ribosome-inactivating proteins (RIPs) are inhibitors with RNAN- glycosidase activity that irreversibly inactivate eukaryotic ribosomes, thereby impairing protein synthesis. In recent years, more than 40 RIPs and lectins belonging to the Sambucus genus have been isolated and characterized to varying degrees. The type 2 RIPs isolated from Sambucus have the peculiarity that although they are enzymatically more active than ricin, they lack the high toxicity of ricin to intact cells and animals. The presence in the same tissue of heterodimeric and tetrameric type 2 RIPs, structurally related monomeric, and homodimeric lectins together with unrelated type 1 RIPs make Sambucus an ideal model for studying these special proteins whose biological role is unknown at present. In the light of the accumulated results on the Sambucus RIPs and lectins, we present here the main findings about structural features and biological activities of these proteins as well as the evolutionary relationship between them and some of their potential uses. © Springer-Verlag Berlin Heidelberg 2010.