The Peptide Antibiotic Corramycin Adopts a β-Hairpin-like Structure and Is Inactivated by the Kinase ComG.

The rapid development of antibiotic resistance, especially among difficult-to-treat Gram-negative bacteria, is recognized as a serious and urgent threat to public health. The detection and characterization of novel resistance mechanisms are essential to better predict the spread and evolution of antibiotic resistance. Corramycin is a novel and modified peptidic antibiotic with activity against several Gram-negative pathogens.

Structure Elucidation, Total Synthesis, Antibacterial In Vivo Efficacy and Biosynthesis Proposal of Myxobacterial Corramycin.

Herein, we describe the myxobacterial natural product Corramycin isolated from Corallococcus coralloides. The linear peptide structure contains an unprecedented (2R,3S)-γ-N-methyl-β-hydroxy-histidine moiety. Corramycin exhibits anti-Gram-negative activity against Escherichia coli (E.

Biosynthesis of the Klebsiella oxytoca Pathogenicity Factor Tilivalline: Heterologous Expression, in Vitro Biosynthesis, and Inhibitor Development.

Tilvalline is a pyrrolo[4,2]benzodiazepine derivative produced by the pathobiont Klebsiella oxytoca and is the causative toxin in antibiotic associated hemorrhagic colitis (AAHC). Heterologous expression of the tilivalline biosynthetic gene cluster along with in vitro reconstitution of the respective NRPS (NpsA, ThdA, NpsB) was employed to reveal a nonenzymatic indole incorporation via a spontaneous Friedel-Crafts-like alkylation reaction. Furthermore, the heterologous system was used to generate novel tilivalline derivatives by supplementation of respective anthranilate and indole precursors.

Total Biosynthesis of the Pyrrolo[4,2]benzodiazepine Scaffold Tomaymycin on an In Vitro Reconstituted NRPS System.

In vitro reconstitution and biochemical analysis of natural product biosynthetic pathways remains a challenging endeavor, especially if megaenzymes of the nonribosomal peptide synthetase (NRPS) type are involved. In theory, all biosynthetic steps may be deciphered using mass spectrometry (MS)-based analyses of both the carrier protein-coupled intermediates and the free intermediates. We here report the "total biosynthesis" of the pyrrolo[4,2]benzodiazepine scaffold tomaymycin using an in vitro reconstituted NRPS system.

Insights into the generation of structural diversity in a tRNA-dependent pathway for highly modified bioactive cyclic dipeptides.

The nocazines are a newly defined family of antibacterial and cytotoxic cyclic dipeptides produced by different actinobacterial species. Here, we identify a nocazine biosynthetic gene cluster in Nocardiopsis dassonvillei and describe the elucidation of the biosynthetic pathway leading to the nocazine family members nocazine E and XR334. Diketopiperazine (DKP) formation is carried out by a tRNA-dependent cyclodipeptide synthase (CDPS) showing an unknown product profile, while tailoring of the DKP-scaffold is achieved through the combined and combinatorial action of a cyclodipeptide oxidase and two distinct SAM-dependent O-/N-methyltransferases.

A tRNA-dependent two-enzyme pathway for the generation of singly and doubly methylated ditryptophan 2,5-diketopiperazines.

A large number of bioactive natural products containing a 2,5-diketopiperazine (DKP) moiety have been isolated from various microbial sources. Especially tryptophan-containing cyclic dipeptides (CDPs) show great structural and functional diversity, while little is known about their biosynthetic pathways. Here, we describe the bioinformatic analysis of a cyclodipeptide synthase (CDPS)-containing gene cluster from Actinosynnema mirum spanning 2.