Large subunit of bacterial ribosome (50S ribosomal subunit)

The **large subunit of the bacterial ribosome** (commonly called the **50S ribosomal subunit**) is one half of the prokaryotic ribosome, a complex molecular machine essential for protein synthesis in all living bacteria[1][6][7]. The 50S subunit is composed mainly of *23S* and *5S ribosomal RNA* molecules and approximately 31 proteins[6]. It joins with the small subunit (30S) during translation to form the functional 70S ribosome[1][6]. The most critical catalytic function of the 50S subunit is its **peptidyl transferase center**, a ribozyme region responsible for forming peptide bonds between amino acids, thus elongating the nascent protein chain[2][6]. Many antibiotics, including macrolides and chloramphenicol, target this subunit, inhibiting bacterial protein synthesis and making it a central therapeutic target in infectious disease management[6]. Key safety concerns with drugs targeting this subunit involve potential bacterial resistance due to mutations, though generally, selectivity for the bacterial ribosome limits toxicity to human cells[6][7].

Other names

50S subunit50S ribosomal subunitProkaryotic large ribosomal subunit

Inhibition of protein synthesis by binding to the large ribosomal subunit, blocking peptide bond formation or exit tunnel for nascent polypeptide chain