On the nature of antibiotic binding sites in ribosomes

The ribosome is an enzyme and enzymes have active sites. Antibiotics that affect ribosomal function can be considered as enzyme inhibitors (or regulators) and it is therefore pertinent to identify their molecular targets as a means of studying the active sites of the particle. The methods available for doing this are considered and, in general terms, the data are evaluated. The conclusion is reached that there exists virtually no compelling evidence that antibiotics bind primarily to ribosomal proteins. Rather, studies of antibiotic resistance in various systems strongly suggest that ribosomal RNA is the primary target for a number of drugs. Moreover, in at least one case (relating to the antibiotic thiostrepton), such an effect can be demonstrated directly. These conclusions imply a fundamental role for RNA in ribosomal function.