Peptide Bond formation in situ
The amino acids in the ribosome are
attached to their respective tRNAs by
an ester bond (R - O - R) between the carboxyl terminus and the amino acceptor stem (left). During
formation of a peptide bond,
the ester bond of the amino acid in the (P)eptidyl site is
cleaved, and Peptidyl Transferase
catalyzes a dehydration reaction between
its carboxyl
terminus and the amino terminus
of the amino acid in the (A)mino site. This transfesr the P-site amino acid to the A-site amino acid, and the original
amino terminus (*)
remains unmodified. The polypeptide thus
"grows" from the amino terminus to the carboxy terminus.
All text material ©2009 by Steven M. Carr