|A ribosome´ true colours. (Top) The large subunit of the ribosome, with proteins in blue and RNA components in orange, grey, and burgundy. Green and red ribbons, tRNAs. (Bottom) The peptidyl transfer mechanism catalysed by the RNA components of
the ribosome. A particular adenosine (A2451 in Escherichia coli) is
rendered unusually basic by its environment within the folded structure;
it is presumed to act as a base and abstract a proton as shown.
Reprinted with permission from T R Cech (2000). Copyright