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Publication Abstract from PubMed

Whereas screening of the small-molecule metabolites produced by most cultivatable microorganisms often results in the rediscovery of known compounds, genome-mining programs allow researchers to harness much greater chemical diversity, and result in the discovery of new molecular scaffolds. Here we report the genome-guided identification of a new antibiotic, klebsazolicin (KLB), from Klebsiella pneumoniae that inhibits the growth of sensitive cells by targeting ribosomes. A ribosomally synthesized post-translationally modified peptide (RiPP), KLB is characterized by the presence of a unique N-terminal amidine ring that is essential for its activity. Biochemical in vitro studies indicate that KLB inhibits ribosomes by interfering with translation elongation. Structural analysis of the ribosome-KLB complex showed that the compound binds in the peptide exit tunnel overlapping with the binding sites of macrolides or streptogramin-B. KLB adopts a compact conformation and largely obstructs the tunnel. Engineered KLB fragments were observed to retain in vitro activity, and thus have the potential to serve as a starting point for the development of new bioactive compounds.

Klebsazolicin inhibits 70S ribosome by obstructing the peptide exit tunnel.,Metelev M, Osterman IA, Ghilarov D, Khabibullina NF, Yakimov A, Shabalin K, Utkina I, Travin DY, Komarova ES, Serebryakova M, Artamonova T, Khodorkovskii M, Konevega AL, Sergiev PV, Severinov K, Polikanov YS Nat Chem Biol. 2017 Aug 28. doi: 10.1038/nchembio.2462. PMID:28846667^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.