Complex sentence: The exact mechanism of action is unknown at this time, but, the 3' position contains an amide linkage instead of the normal ester linkage of tRNA, the amide bond makes the molecule much more resistant to hydrolysis and stopped the ribosome.
Split into simpler sentences: The exact mechanism of action is unknown at this time but the 3' position contains an amide linkage instead of the normal ester linkage of tRNA. The amide bond makes the molecule much more resistant to hydrolysis and stopped the ribosome.