The Structure and Action of Ribosome‐inactivating Proteins

Ribosome-inhibiting proteins, RIPs, are widespread in nature and include plant cytotoxins like ricin as well as bacterial toxins, like those from Shigella. RIPs act by depurinating an invariant adenine from rRNA and thereby inhibiting protein synthesis; they have evolved to near enzymatic perfection. The X-ray structures of RIPs have allowed this exquisite mechanism to be understood. Furthermore, knowledge of the structure has facilitated the design of specific inhibitors that may be useful as drugs in the future.