Ricin removes an adenine from a specific portion of the 28S rRNA called the , or SRL. This leads to reduced binding of elongation factors to the ribosome and reduced synthesis of proteins. It also triggers apoptosis via activation of the JNK pathway (citation).
While the structure of an eukaryotic ribosome is known, it is not at the level of detail to be able to precisely map this location. What is known about the location of the depurination is:
--The depurination occurs in the sacrin-ricin loop of the 28S subunit at a GAGA sequence at A4324 (eukaryotic numbering)
--L3 and L6 bind to this same loop
