Selectivity and Specificity Reconsidered

Abstract

Despite the broad scope of the inhibitors of translation mentioned above and presented in Tables 2–4, there are some cases in which certain antibiotics appear to have narrower spectra of selectivity. Thus lincomycin is very active on ribosomes from gram-positive bacteria and moderately active on blue-green algae ribosomes, but has low activity on ribosomes from gram-negative bacteria in preventing peptide bond formation (Chang and Weisblum, 1967; Celma, 1971; Monro et al., 1971). Furthermore, tenuazonic acid inhibits protein synthesis by mammalian but not by yeast ribosomes (Carrasco and Vázquez, 1973b), cycloheximide is inactive on ribosomes of wild type Saccharomyces fragilis (Rao and Grollman, 1967) and Saccharomyces lactis,whi1e fusidic acid is inactive on ribosomes from Neurospora crassa mitochondria (Grandi, Helma and Kuntzel, 1971) and in protein synthesizing systems from sporulating Bacillus subtilis (Fortnagel and Bergman, 1973). Furthermore, normal ribosomes, sensitive to fusidic acid, are required for the initiation of normal sporulation, but ribosomes functioning throughout the development period after septum formation do not form the fusidic acid-EF-G · GTP · ribosome complex and are therefore resistant to fusidic acid (Fortnagel and Freese, 1977).