Final answer:
Toxins and antibiotics can function as inhibitors of protein synthesis, selectively targeting bacterial protein synthesis. Shiga toxin and diphtheria toxin are examples of such inhibitors. Tetracycline and its derivatives are antibiotics used to treat bacterial infections by exploiting structural differences between prokaryotic and eukaryotic ribosomes.
Step-by-step explanation:
Some toxins and antibiotics function by inhibiting protein synthesis in cells. For example, Shiga toxin, produced by certain E. coli strains like EHEC, inhibits protein synthesis, impairing the pathogen's virulence when this gene is inactivated. Antibiotics such as tetracycline bind to the bacterial ribosome and inhibit protein synthesis by blocking the A-site, thus preventing the binding of aminoacyl-tRNA and interfering with the elongation of the protein chain. Tetracycline derivatives like doxycycline are commonly used to treat various bacterial infections without harming the patient's own cells.
Other examples of protein synthesis inhibitors include diphtheria toxin, which inhibits protein synthesis by inactivating elongation factor 2, and aminoglycosides, which bind to the 30S subunit of bacterial ribosomes, ultimately causing mismatches during protein synthesis that can lead to cell death. Puromycin and tetracycline are specific inhibitors that target prokaryotic ribosomes, leveraging the structural differences between prokaryotic (70S) and eukaryotic (80S) ribosomes to achieve selectivity.
Not all effects on protein synthesis are harmful to host organisms, as in the case of protein synthesis inhibitors used as therapeutic agents. These inhibitors can selectively target bacterial protein synthesis while sparing the eukaryotic hosts, thanks to the differences in ribosomal structures. This selective inhibition is crucial for the therapeutic efficacy of antibiotics in treating bacterial infections without harming the patient.