RESUMO
Hybrid genome-mining/15N-NMR was used to target compounds containing piperazate (Piz) residues, leading to the discovery of caveamides A (1) and B (2) from Streptomyces sp. strain BE230, isolated from New Rankin Cave (Missouri). Caveamides are highly dynamic molecules containing an unprecedented ß-ketoamide polyketide fragment, two Piz residues, and a new N-methyl-cyclohexenylalanine residue. Caveamide B (2) exhibited nanomolar cytotoxicity against several cancer cell lines and nanomolar antimicrobial activity against MRSA and E. coli.
Assuntos
Escherichia coli , Staphylococcus aureus Resistente à Meticilina , Streptomyces , Humanos , Estrutura Molecular , Streptomyces/química , Escherichia coli/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Antibacterianos/farmacologia , Antibacterianos/química , Antibacterianos/isolamento & purificação , Testes de Sensibilidade Microbiana , Antineoplásicos/farmacologia , Antineoplásicos/química , Antineoplásicos/isolamento & purificação , Alanina/química , Alanina/farmacologia , Alanina/análogos & derivados , Ensaios de Seleção de Medicamentos Antitumorais , Peptídeos/química , Peptídeos/farmacologia , Peptídeos/isolamento & purificação , Linhagem Celular Tumoral , PiridazinasRESUMO
Piperazic acid (Piz) is a nonproteinogenic amino acid possessing a rare nitrogen-nitrogen bond. However, little is known about how Piz is incorporated into nonribosomal peptides, including whether adenylation domains specific to Piz exist. In this study, we show that free piperazic acid is directly adenylated and then incorporated into the incarnatapeptin nonribosomal peptides through isotopic incorporation studies. We also use in vitro reconstitution to demonstrate adenylation of free piperazic acid with a three-domain nonribosomal peptide synthetase from the incarnatapeptin gene cluster. We furthermore use bioinformatics and site-directed mutagenesis to outline consensus sequences for the adenylation of piperazic acid, which can now be used for the prediction of gene clusters linked to piperazic-acid-containing peptides. Finally, we discover a fusion protein of a piperazate synthase and an adenylation domain, highlighting the close biosynthetic relationship of piperazic acid formation and its adenylation. Altogether, our work demonstrates the evolution of biosynthetic systems for the activation of free piperazic acid through adenylation, a pathway we suggest is likely to be employed in the majority of pathways to piperazic-acid-containing peptides.
Assuntos
Peptídeo Sintases , Piridazinas , Nitrogênio , Peptídeo Sintases/metabolismo , Peptídeos/química , Piridazinas/química , Especificidade por SubstratoRESUMO
Methods for the focused isolation of low-abundance natural products with specific chemical substructures could expand known bioactive chemical diversity for drug discovery. Here we report the combined use of genome mining and an 15N NMR-based screening method for the targeted isolation of the low-abundance piperazic-acid-containing peptides incarnatapeptins A (1) and B (3). Incarnatapeptin B (3) shows in vitro cytotoxicity to LNCaP prostate cancer cells.
Assuntos
Antineoplásicos/farmacologia , Produtos Biológicos/farmacologia , Streptomyces/química , Antineoplásicos/química , Antineoplásicos/isolamento & purificação , Produtos Biológicos/química , Produtos Biológicos/isolamento & purificação , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Espectroscopia de Ressonância Magnética , Isótopos de Nitrogênio , Prótons , Streptomyces/genéticaRESUMO
Covering: up to the end of 2018 Piperazic acid is a cyclic hydrazine and a non-proteinogenic amino acid found in diverse non-ribosomal peptide (NRP) and hybrid NRP-polyketide (PK) structures. Piperazic acid was first identified as a residue in the monamycins in 1959. Since then, the piperazic acid residue has been found in >30 families of natural products, representing >140 compounds. Many of these compounds have potent biological activity, ranging from anti-malarial to anti-apoptotic to anti-bacterial activity, although high toxicity often accompanies this potent biological activity. Recently, we identified a piperazate synthase, responsible for N-N bond formation to give piperazic acid. Here, we review piperazic acid-containing natural products discovered from 1959 to 2018, with an emphasis on the biosynthetic routes to these natural products.