The large ribosomal subunit binds with several different antibiotics to recognize the contact points between the antibiotic and the ribosome. For instance, macrolides are a family of structurally similar compounds that contains the prevalent antibiotics like erythromycin and Zithromax, and can inhibits the protein synthesis by stopping the ribosome on the mRNA (messenger ribonucleic acid) molecule by attaching to a particular region on the 23S RNA in the large ribosomal subunit that leads to the obstruction of exit tunnel from where the growing polypeptide comes out from the large subunit.
Due to slight sequence differences among the rRNAs of prokaryotes and eukaryotes, the macrolides containing antibiotics only stops the bacterial translation. But some pathogenic bacteria that have developed resistance to the antibiotics and seem to have ribosomal mutation so as to create the exit tunnel larger. Therefore, information of how antibiotics attach to ribosomes facilitates how the ribosome functions and how to create new antibiotics that can be effective against resistant mutants.