Inhibition of translation termination by the antimicrobial peptide Drosocin

Area of Science:

• Molecular Biology
• Biochemistry
• Antimicrobial Peptides

Background:

• Proline-rich antimicrobial peptides (PrAMPs) are known to inhibit protein synthesis via ribosomal binding.
• The specific target and mechanism of action for Drosocin (Dro), a fruit fly PrAMP, remain uncharacterized.

Purpose of the Study:

• To elucidate the molecular target and mechanism of action of Drosocin (Dro).
• To classify Dro within the known types of PrAMPs based on its function.

Main Methods:

• Ribosome profiling and biochemical assays were employed to determine Dro's interaction with the translation machinery.
• Analysis of a mutant library of Dro was performed to identify key residues involved in target binding.

Main Results:

• Drosocin (Dro) was found to arrest ribosomes specifically at stop codons, likely by sequestering class 1 release factors.
• This mechanism places Dro in the type II PrAMP class, similar to apidaecin (Api).
• Distinct from Api, Dro's interaction with the ribosome involves multiple residues distributed across the peptide, with single substitutions significantly impacting its activity.

Conclusions:

• Drosocin (Dro) functions as a type II PrAMP by inhibiting protein synthesis through ribosome arrest at stop codons.
• The unique, multi-residue interaction profile of Dro suggests potential for developing novel antimicrobial agents with enhanced specificity and efficacy.