The
23S rRNA is a 2904
nt long (in
E. coli) component of the large subunit (
50S) of the bacterial ribosome. The ribosomal
peptidyl transferase activity resides in domain V of this rRNA, and this domain is the most common binding site for antibiotics that inhibit translation. A well-known member of this antibiotic class,
Chloramphenicol, acts by inhibiting peptide bond formation, with recent 3D-structural studies showing two different binding sites depending on the species of ribosome.
Linezolid and
quinupristin-dalfopristin also bind to the 23S rRNA, and cross-resistance has been demonstrated between these antibiotics.