[reaction: see text] Cyclic tetrapeptides are an intriguing class of natural products. To synthesize highly strained cyclic tetrapeptides we developed a macrocyclization strategy that involves the inclusion of 2-hydroxy-6-nitrobenzyl (HnB) group at the N-terminus and in the "middle" of the sequence. The N-terminal auxiliary performs a ring closure/ring contraction role, and the backbone auxiliary promotes cis amide bonds to facilitate the otherwise difficult ring contraction. Following this route, the all-L cyclic tetrapeptide cyclo-[Tyr-Arg-Phe-Ala] was successfully prepared.
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http://dx.doi.org/10.1021/ol034907o | DOI Listing |
J Nat Prod
December 2024
Department of Chemistry, University of Kalyani, Kalyani 741235 West Bengal, India.
A concise synthetic route to an epimer of the recently isolated biologically active cyclic tetrapeptide koshidacin B has been developed, which featured a late-stage functionalization of a macrocyclic scaffold through a cross metathesis reaction. The synthetic 9--koshidacin B showed marginal differences in spectroscopic behavior with that of the natural product but exhibited conformational preferences similar to those reported for analogous substrate chlamydocin. Moreover, it exhibited a useful level of selective inhibition of biologically relevant enzyme histone deacetylase 1 with an IC value of 0.
View Article and Find Full Text PDFbioRxiv
November 2024
James Tarpo Jr. and Margaret Tarpo Department of Chemistry, Purdue University, West Lafayette, IN 47906.
Cyclic tetrapeptides (CTPs) are a diverse class of natural products with a broad range of biological activities. However, they are extremely challenging to synthesize due to the ring strain associated with their small ring size. While chemical methods have been developed to access CTPs, they generally require the presence of certain amino acids, limiting their substrate scopes.
View Article and Find Full Text PDFInsects
September 2024
Department of Plant Medicals, Andong National University, Andong 36729, Republic of Korea.
Entomopathogenic bacteria, classified into the genus , exhibit a dual lifestyle as mutualistic symbionts to nematodes and as pathogens to a broad range of insects. Bacterial virulence depends on toxin proteins that induce toxemia and various immunosuppressive secondary metabolites that cause septicemia. Particularly, the immunosuppressive properties of bacteria determine the variability of their insecticidal activities.
View Article and Find Full Text PDFJ Nat Prod
October 2024
The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, So̷ltoft Plads, building 220, 2800 Kgs. Lyngby, Denmark.
Genome analysis of sp. CA-103260 revealed a putative lipopeptide-encoding biosynthetic gene cluster (BGC) that was cloned into a bacterial artificial chromosome (BAC) and heterologously expressed in M1152. As a result, a novel cyclic lipo-tetrapeptide containing two diaminopropionic acid residues and an exotic ,-acetonide ring, kutzneridine A (), was isolated and structurally characterized.
View Article and Find Full Text PDFProtein Sci
October 2024
Department of Pharmacy and Biotechnology, University of Bologna, Bologna, Italy.
The energetic metabolism of cancer cells relies on a substantial commitment of pyruvate to the catalytic action of lactate-generating dehydrogenases. This coupling mainly depends on lactate dehydrogenase A (LDH-A), which is overexpressed in different types of cancers, and therefore represents an appealing therapeutic target. Taking into account that the activity of LDHs is exclusively exerted by their tetrameric forms, it was recently shown that peptides perturbing the monomers-to-tetramer assembly inhibit human LDH-A (hLDH-A).
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