Peptidyl transferase

The peptidyl transferase is an aminoacyltransferase (EC 2.3.2.12) as well as the primary enzymatic function of the ribosome, which forms peptide bonds between adjacent amino acids using tRNAs during the translation process of protein biosynthesis. The substrates for the peptidyl transferase reaction are two tRNA molecules, one bearing the growing peptide chain and the other bearing the amino acid that will be added to the chain. The peptidyl chain and the amino acids are attached to their respective tRNAs via ester bonds to the O atom at the CCA-3' ends of these tRNAs.[1]:437–8 Peptidyl transferase is an enzyme that catalyzes the addition of an amino acid residue in order to grow the polypeptide chain in protein synthesis.[2] It is located in the large ribosomal subunit, where it catalyzes the peptide bond formation.[3] It is composed entirely of RNA. The alignment between the CCA ends of the ribosome-bound peptidyl tRNA and aminoacyl tRNA in the peptidyl transferase center contribute to its ability to catalyze these reactions.[4] This reaction occurs via nucleophilic displacement. The amino group of the aminoacyl tRNA attacks the terminal carboxyl group of the peptidyl tRNA.[3] Peptidyl transferase activity is carried out by the ribosome. Peptidyl transferase activity is not mediated by any ribosomal proteins but by ribosomal RNA (rRNA), a ribozyme. Ribozymes are the only enzymes which are not made up of proteins, but ribonucleotides. All other enzymes are made up of proteins. This RNA relic is the most significant piece of evidence supporting the RNA World hypothesis.

  • In Prokaryotes, the 50S (23S component) ribosome subunit contains the peptidyl transferase component and acts as a ribozyme. The peptidyl transferase center on the 50S subunit lies at the lower tips (acceptor ends) of the A- and O- site tRNAs.[1]:1062
  • In Eukaryotes, the 60S (28S component) ribosome subunit contains the peptidyl transferase component and acts as the ribozyme.
Peptidyl transferase
Identifiers
EC number2.3.2.12
CAS number9059-29-4
Databases
IntEnzIntEnz view
BRENDABRENDA entry
ExPASyNiceZyme view
KEGGKEGG entry
MetaCycmetabolic pathway
PRIAMprofile
PDB structuresRCSB PDB PDBe PDBsum

Peptidyl transferases are not limited to translation, but there are relatively few enzymes with this function.

Antibiotic target

The following protein synthesis inhibitors target peptidyl transferase:

See also

References
  1. Garrett RH, Grisham CM (2012). Biochemistry (5th ed.). Belmont CA: Brooks/Cole. ISBN 978-1-133-10629-6.
  2. "Peptidyl Transferase - Acyltransferases - Transferases - Enzymes - Products". www.axonmedchem.com. Retrieved 2018-11-10.
  3. "Part Three: Gene Expression and Protein Synthesis". www.bx.psu.edu. Retrieved 2018-10-30.
  4. Moore PB, Steitz TA (February 2003). "After the ribosome structures: how does peptidyl transferase work?". RNA. 9 (2): 155–9. doi:10.1261/rna.2127103. PMC 1370378. PMID 12554855.
  5. Catalyst University, Peptidyl Transferase/Ribosome Physiology, Biochemistry, and Mechanism, retrieved 2018-10-07
  6. Gu Z, Harrod R, Rogers EJ, Lovett PS (June 1994). "Anti-peptidyl transferase leader peptides of attenuation-regulated chloramphenicol-resistance genes". Proceedings of the National Academy of Sciences of the United States of America. 91 (12): 5612–6. Bibcode:1994PNAS...91.5612G. doi:10.1073/pnas.91.12.5612. PMC 44046. PMID 7515506.
  7. Long KS, Hansen LH, Jakobsen L, Vester B (April 2006). "Interaction of pleuromutilin derivatives with the ribosomal peptidyl transferase center" (PDF). Antimicrobial Agents and Chemotherapy. 50 (4): 1458–62. doi:10.1128/AAC.50.4.1458-1462.2006. PMC 1426994. PMID 16569865.
  8. Kaiser G. "Protein synthesis inhibitors: macrolides mechanism of action animation. Classification of agents". Pharmamotion. The Community College of Baltimore County. Archived from the original on December 26, 2008. Retrieved July 31, 2009.
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