Ribosomes are the universal ribonucleoprotein particles that translate the genetic code into proteins. They are built of two subunits that associate upon initiation of protein synthesis. Typical eubacterial ribosomes (70S) consist of 57 different molecules (3 rRNAs and 54 proteins) and can dissociate into a small (30S) and a large subunit (50S).
The small subunit is responsible for the formation of the initiation complex, performs the decoding of the genetic information, and controls the fidelity of codon-anticodon interactions. The large subunit catalyzes the peptide bond formation and provides the path for the nascent polypeptide chain.
Ribosomes are a major target for natural and synthetic antibiotics. Detailed knowledge of antibiotic binding sites is the key to understand the mechanisms of drug action. Conversely, drugs are excellent tools for studying the ribosome function.
Structural models of the ribosomal subunits in complex with antibiotics should not only enable a rational approach for antibiotic development and therapy strategies but could also be used to identify new antibiotic target sites on the eubacterial ribosome.