Ricin: structure, mode of action, and some current applications.

摘要: Ricin is an abundant protein component of Ricinus communis seeds (castor beans) that exquisitely toxic to mammalian cells. It consists enzymic polypeptide catalyzes the N-glycosidic cleavage a specific adenine residue from 28S ribosomal RNA, joined by single disulfide bond galactose (cell)-binding lectin. The enzymatic activity renders ribosomes containing depurinated RNA incapable synthesis. bipartite molecular structure ricin allows it bind cell surface, enter via endocytic uptake, and deliver catalytically active into cytosol where irreversibly inhibits synthesis causing death. Because its cytotoxic potency, modified being used for selective killing unwanted cells toxigenic ablation lineages in transgenic organisms.