Tur1A peptide

Proline-rich antimicrobial peptides (PrAMPs) are antibacterial components of the immune system of some animals. Mardirossian et al. identified two PrAMPs in the artiodactyl Tursiops truncatus (bottlenose dolphin), Tur1A and Tur1B. Tur1A was shown to inhibit bacterial protein synthesis by binding to the ribosome. The proline-rich AMPs Tur1A and Tur1B were identified in the bottlenose dolphin. Tur1A is non-lytic and inhibits bacterial protein synthesis. Tur1A binds within the ribosomal tunnel and prevents translation elongation. Tur1B is a poor inhibitor of translation and thus probably has another target. Peptide truncation indicates that the antimicorbial activity is mainly located at the N-terminal region residues 1-16 (MIC 4 uM). While the intact molecule shows similar activity against sbmA and yjiL KO strains, the truncated peptides 1-16, 8-24, and 16-32 are inactive, indicating the entire sequence do not depend on the Pro-rich peptide transporters for activity. Tur1A inhibits E. coli protein translation by binding to the exit tunnel of ribosome in a reversed order. Interestingly, residues 1-16 plays a major role in ribosome binding.