Antibiotic mechanism of action. Computer artwork showing the sites where two different families of antibiotics exert their effects on messenger RNA (mRNA) during the translation stage of protein synthesis. During translation a ribosome (large, beige) moves left to right reading the mRNA and facilitating the binding of amino acids (coloured spheres) to each other to form a protein. Both Macrolide and Tetracycline antibiotics disrupt bacterial cell growth through inhibiting the translation stage of protein synthesis.