Screening assay for ribosomal antibiotics

A method for identifying ribosomal antimicrobial substances being selective for microbial but not for mitochondrial and cytosolic ribosomes, comprising the following steps:

• a) providing
• (i) at least one bacterial strain or a functionally equivalent cell-free biological system with microbial ribosomes, and
• (ii) at least one bacterial strain or a functionally equivalent cell-free biological system with chimeric mitochondrial bacterial ribosomes comprising chimeric rRNA, and
• (iii) at least one bacterial strain or a functionally equivalent cell-free biological system with chimeric cytosolic bacterial ribosomes comprising chimeric rRNA;
• b) contacting a candidate ribosomal antimicrobial substance with each of the bacterial strains or a functionally equivalent cell-free biological system according to a);
• c) determining an interaction of the candidate ribosomal antimicrobial substance with one or more of the ribosomes of each of the bacterial strains or a functionally equivalent cell-free biological system according to a);
• and
• d) identifying the candidate ribosomal antimicrobial substance as being selective for microbial ribosomes and not for mitochondrial ribosomes and cytosolic ribosomes, when said candidate ribosomal antimicrobial substance interacts with microbial ribosomes but does not interact with chimeric mitochondrial bacterial ribosomes and with cytosolic bacterial ribosomes of the bacterial strains of a).