The Dolphin Proline-Rich Antimicrobial Peptide Tur1A Inhibits Protein Synthesis by Targeting the Bacterial Ribosome

Cell Chem Biol. 2018 May 17;25(5):530-539.e7. doi: 10.1016/j.chembiol.2018.02.004. Epub 2018 Mar 8.


Proline-rich antimicrobial peptides (PrAMPs) internalize into susceptible bacteria using specific transporters and interfere with protein synthesis and folding. To date, mammalian PrAMPs have so far been identified only in artiodactyls. Since cetaceans are co-phyletic with artiodactyls, we mined the genome of the bottlenose dolphin Tursiops truncatus, leading to the identification of two PrAMPs, Tur1A and Tur1B. Tur1A, which is orthologous to the bovine PrAMP Bac7, is internalized into Escherichia coli, without damaging the membranes, using the inner membrane transporters SbmA and YjiL/MdM. Furthermore, like Bac7, Tur1A also inhibits bacterial protein synthesis by binding to the ribosome and blocking the transition from the initiation to the elongation phase. By contrast, Tur1B is a poor inhibitor of protein synthesis and may utilize another mechanism of action. An X-ray structure of Tur1A bound within the ribosomal exit tunnel provides a basis to develop these peptides as novel antimicrobial agents.

Keywords: Bac7; PrAMP; Tur1A; Tur1B; antibiotic; cathelicidin; dolphin; proline-rich antimicrobial peptide; ribosome.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Anti-Bacterial Agents / chemistry*
  • Anti-Bacterial Agents / pharmacology*
  • Antimicrobial Cationic Peptides / chemistry*
  • Antimicrobial Cationic Peptides / pharmacology*
  • Crystallography, X-Ray
  • Dolphins
  • Escherichia coli / drug effects*
  • Escherichia coli / metabolism
  • Escherichia coli Infections / drug therapy
  • Escherichia coli Proteins / metabolism
  • Humans
  • Models, Molecular
  • Protein Biosynthesis / drug effects*
  • Ribosomes / drug effects*
  • Ribosomes / metabolism


  • Anti-Bacterial Agents
  • Antimicrobial Cationic Peptides
  • Escherichia coli Proteins