Charting the sequence-activity landscape of peptide inhibitors of translation termination

Apidaecin (Api), an unmodified 18-amino-acid-long proline-rich antibacterial peptide produced by bees, has been recently described as a specific inhibitor of translation termination. It invades the nascent peptide exit tunnel of the postrelease ribosome and traps the release factors preventing their recycling. Api binds in the exit tunnel in an extended conformation that matches the placement of a nascent polypeptide and establishes multiple contacts with ribosomal RNA (rRNA) and ribosomal proteins. Which of these interactions are critical for Api's activity is unknown. We addressed this problem by analyzing the activity of all possible single-amino-acid substitutions of the Api variants synthesized in the bacterial cell. By conditionally expressing the engineered api gene, we generated Api directly in the bacterial cytosol, thereby bypassing the need for importing the peptide from the medium. The endogenously expressed Api, as well as its N-terminally truncated mutants, retained the antibacterial properties and the mechanism of action of the native peptide. Taking advantage of the Api expression system and next-generation sequencing, we mapped in one experiment all the single-amino-acid substitutions that preserve or alleviate the on-target activity of the Api mutants. Analysis of the inactivating mutations made it possible to define the pharmacophore of Api involved in critical interactions with the ribosome, transfer RNA (tRNA), and release factors. We also identified the Api segment that tolerates a variety of amino acid substitutions; alterations in this segment could be used to improve the pharmacological properties of the antibacterial peptide.

Medienart:

E-Artikel

Erscheinungsjahr:

2021

Erschienen:

2021

Enthalten in:

Zur Gesamtaufnahme - volume:118

Enthalten in:

Proceedings of the National Academy of Sciences of the United States of America - 118(2021), 10 vom: 09. März

Sprache:

Englisch

Beteiligte Personen:

Baliga, Chetana [VerfasserIn]
Brown, Tyler J [VerfasserIn]
Florin, Tanja [VerfasserIn]
Colon, Sarah [VerfasserIn]
Shah, Vallari [VerfasserIn]
Skowron, Kornelia J [VerfasserIn]
Kefi, Amira [VerfasserIn]
Szal, Teresa [VerfasserIn]
Klepacki, Dorota [VerfasserIn]
Moore, Terry W [VerfasserIn]
Vázquez-Laslop, Nora [VerfasserIn]
Mankin, Alexander S [VerfasserIn]

Links:

Volltext

Themen:

123997-21-7
Antibiotic
Antimicrobial Cationic Peptides
Apidaecin
Journal Article
Nascent peptide exit tunnel
Protein Synthesis Inhibitors
RNA, Bacterial
RNA, Ribosomal
Research Support, U.S. Gov't, Non-P.H.S.
Ribosome
Translation termination

Anmerkungen:

Date Completed 16.08.2021

Date Revised 06.09.2021

published: Print

Citation Status MEDLINE

doi:

10.1073/pnas.2026465118

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM322316650