Search

In den letzten Jahrzehnten ist die Entwicklungspipeline neuer Antibiotika gegen Gram‐negative Bakterien nahezu zum Erliegen gekommen, da die meisten entdeckten Kandidaten Defizite im Bereich der Wirksamkeit, ihrer pharmakokinetischen Eigenschaften oder eine zu hohe Toxizität aufwiesen. Die Darobactine, eine vielversprechende neue Peptid‐Klasse, binden an BamA, ein zuvor von Antibiotika nicht adressiertes Zielprotein der äußeren Membran. Wir haben bereits gezeigt, dass durch Biosynthese‐Modifikationen in einem heterologen Wirt neuartige Darobactine mit erhöhter antibakterieller Aktivität erzeugt werden können. Nun verwenden wir eine optimierte Reinigungsmethode und präsentieren Kryo‐EM‐Strukturen des Bam‐Komplexes mit Darobactin 9 (D9), welche als Basis für die biotechnologische Herstellung von zwanzig neuen Darobactinen, einschließlich halogenierter Analoga, dient. Das neu entwickelte Darobactin 22 bindet enger an BamA und übertrifft das bereits hohe Aktivitätsprofil von D9 gegen klinisch relevante Krankheitserreger, wie Carbapenem‐resistente Acinetobacter baumannii, um das bis zu 32‐fache, ohne erkennbare Anzeichen von Toxizität. [ABSTRACT FROM AUTHOR]

Inside Cover: Darobactins Exhibiting Superior Antibiotic Activity by Cryo-EM Structure Guided Biosynthetic Engineering (Angew. Antibiotics, BamA, CRAB, Cryo-Electron Microscopy, Natural Products Keywords: Antibiotics; BamA; CRAB; Cryo-Electron Microscopy; Natural Products EN Antibiotics BamA CRAB Cryo-Electron Microscopy Natural Products 1 1 1 01/04/23 20230109 NES 230109 B Darobactins b bind to the novel antibiotic target BamA in the outer membrane BAM-complex of Gram-negative pathogens. [Extracted from the article]

The new derivative D22 was created through cryo-EM structure- and activity-guided biosynthetic engineering as described by Thomas C. Marlovits, Jennifer Herrmann, Rolf Müller et al. in their Research Article (e202214094), and showed superior potency against multidrug-resistant clinical isolates, for which most antibiotics on the market are no longer effective. The renewal of the outer membrane proteins is prevented and bacteria are lysed. Keywords: Antibiotika; BamA; CRAB; Kryo-Elektronenmikroskopie; Naturstoffe DE Antibiotika BamA CRAB Kryo-Elektronenmikroskopie Naturstoffe 1 1 1 01/04/23 20230109 NES 230109 B Darobactins b bind to the novel antibiotic target BamA in the outer membrane BAM-complex of Gram-negative pathogens. [Extracted from the article]

The recently identified natural product NOSO-95A from entomopathogenic Xenorhabdus bacteria, derived from a biosynthetic gene cluster (BGC) encoding a non-ribosomal peptide synthetase (NRPS), was the first member of the odilorhabdin class of antibiotics. This class exhibits broad-spectrum antibiotic activity and inspired the development of the synthetic derivative NOSO-502, which holds potential as a new clinical drug by breaking antibiotic resistance. While the mode of action of odilorhabdins was broadly investigated, their biosynthesis pathway remained poorly understood. Here we describe the heterologous production of NOSO-95A in Escherichia coli after refactoring the complete BGC. Since the production titer was low, NRPS engineering was applied to uncover the underlying biosynthetic principles. For this, modules of the odilorhabdin NRPS fused to other synthetases were co-expressed with candidate hydroxylases encoded in the BGC allowing the characterization of the biosynthesis of three unusual amino acids and leading to the identification of a prodrug-activation mechanism by deacylation. Our work demonstrates the application of NRPS engineering as a blueprint to mechanistically elucidate large or toxic NRPS and provides the basis to generate novel odilorhabdin analogues with improved properties in the future., (© 2024 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.)

Over recent decades, the pipeline of antibiotics acting against Gram-negative bacteria is running dry, as most discovered candidate antibiotics suffer from insufficient potency, pharmacokinetic properties, or toxicity. The darobactins, a promising new small peptide class of drug candidates, bind to novel antibiotic target BamA, an outer membrane protein. Previously, we reported that biosynthetic engineering in a heterologous host generated novel darobactins with enhanced antibacterial activity. Here we utilize an optimized purification method and present cryo-EM structures of the Bam complex with darobactin 9 (D9), which served as a blueprint for the biotechnological generation of twenty new darobactins including halogenated analogs. The newly engineered darobactin 22 binds more tightly to BamA and outperforms the favorable activity profile of D9 against clinically relevant pathogens such as carbapenem-resistant Acinetobacter baumannii up to 32-fold, without observing toxic effects., (© 2022 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.)