The ribosome: a versatile mega-ribozyme

The catalytic center of ribosomes is made up of ribonucleic acid (RNA). Catalysis is predominantly by orienting the substrates. The catalytic center is quite flexible; besides assembling amino acids to form proteins it catalyzes the hydrolytic liberation of the proteins after completion and accepts unnatural amino acids. This is utilized in Biotechnology for synthesizing proteins with particular properties. Peptide bond formation usually takes place spontaneously. However, linking several proline residues requires a special translation factor.