50S, koja je ekvivalentna sa 60S ribozomalnom podjedinicom eukariotskih ćelija, je velika podjedinica 70S ribozomaprokariota. 50S podjedinica se prvenstveno sastoji od proteina ali isto tako sadrži i jednolančanu RNK poznatu kao ribozomna RNK (rRNK). rRNK formira sekundarne i tercijarne strukture kojima se održava aktivna struktura ribozoma.
^Ban N, Nissen P, Hansen J, Moore P, Steitz T (2000). „The complete atomic structure of the large ribosomal subunit at 2.4 A resolution”. Science. 289 (5481): 905—20. PMID10937989. doi:10.1126/science.289.5481.905.
Nissen P, Hansen J, Ban N, Moore P, Steitz T (2000). “The structural basis of ribosome activity in peptide bond synthesis”. Science 289 (5481): 920-29.
Schmeing T, Huang K, Strobel S, Steitz T (2005). “An induced-fit mechanism to promote peptide bond formation and exclude hydrolysis of peptidyl-tRNA”. Nature 438: 520-24.
Basu A, Ghosh J, Bhattacharya A, Pal S, Chowdhury S, DasGupta C (2003). “Splitting of ribosome into its subunits by unfolded polypeptide chains”. Current Science 84: 1123-25.