title: Mechanism of action of ricin and related toxic lectins on eukaryotic ribosomes.
abstract: We have studied on the mechanism of ricin action on rat liver ribosomes and present evidence which shows that the toxin inactivates ribosomes by modifying two bases at positions G-4323 and A-4324 of 28S rRNA adjacent to alpha-sarcin cleavage site. Further results showing that those phosphodiester bonds are very labile against alkaline digestion and aniline-treatment strongly suggest that these purine bases are removed by N-glycosidase activity of the toxin. In parallel, we also present evidence showing that abrin and modeccin have the same activity on eukaryotic ribosomes as ricin does.
mesh_terms: D000818:Animals; D037102:Lectins / Q000494:pharmacology*; D008099:Liver / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D012270:Ribosomes / Q000187:drug effects* / Q000378:metabolism; D012276:Ricin / Q000494:pharmacology*; D013329:Structure-Activity Relationship
chemical_list: D037102:Lectins; D012276:Ricin