Biaryl and heterobiaryl-containing cyclic peptides represent promising scaffolds for the development of bioactive molecules. The incorporation of heterobiaryl motifs continues to pose synthetic challenges, which is partially due to the difficulties in effecting late-stage metal-catalyzed cross-couplings. We report a new strategy to form heterobiaryls that is based on trapping nitrilium ions. The sequence is exemplified using oxadiazole- and oxazole-containing biaryl linkages. NMR analysis and molecular dynamics simulations reveal structural control elements common to each member of the heterobiaryl containing peptide family in this study. Strategic substitutions on the C-terminal aminobenzoic acid moiety paired with installation of oxadiazole or oxazole heterobiaryl backbone linkages allow for the modulation of peptide backbone conformation, which should assist efforts to optimize the biophysical properties of peptide macrocycles.
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http://dx.doi.org/10.1039/d3sc03058j | DOI Listing |
PLoS One
January 2025
Institute of Sport Sciences, Jerzy Kukuczka Academy of Physical Education in Katowice, Katowice, Poland.
Curcumin is known for its potential health benefits; however, the evidence remains inconclusive regarding its necessity as a supplement for athletes during the preparatory phase of training. This study aimed to assess the effect of 6-week curcumin supplementation at a dose of 2g/day on selected inflammatory markers, blood count, and brain-derived neurotropic factor (BDNF) levels in middle-aged amateur long-distance runners during the preparatory period of a macrocycle. Thirty runners were randomly assigned to either a curcumin-supplemented group (CUR, n = 15) or a placebo group (PLA, n = 15).
View Article and Find Full Text PDFChemistry
January 2025
Australian National University, Research School of Chemistry, Sullivans Creek Road, ACT 2601, Canberra, AUSTRALIA.
Constrained peptides possess excellent properties for identifying lead compounds in drug discovery. While it has become increasingly straightforward to discover selective high-affinity peptide ligands, especially through genetically encoded libraries, their stability and bioavailability remain significant challenges. By integrating macrocyclization chemistry with bismuth binding, we generated series of linear, cyclic, bicyclic, and tricyclic peptides with identical sequences.
View Article and Find Full Text PDFOrg Lett
January 2025
State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zu Chong Zhi Road, Shanghai 201203, China.
Here, we report on methods for late-stage peptide diversification through palladium-catalyzed site-selective C(sp)-H amination of tryptophan residues at the C4 position, utilizing tryptophan-amine cross-links. Our strategy enables practical access to C-N bonds, facilitating the construction of cyclopeptides via late-stage cyclodimerization of structurally complex peptides, which poses significant challenges for organic synthesis. The synthetic utility of this protocol is demonstrated through the synthesis of 30- to 38-membered macrocyclic peptides.
View Article and Find Full Text PDFMicrob Cell Fact
January 2025
Chair of Technical Biochemistry, Technische Universität Dresden, Bergstraße 66, 01069, Dresden, Germany.
Background: The biosynthesis of the natural product family of the polycyclic tetramate macrolactams (PoTeMs) employs an uncommon iterative polyketide synthase/non-ribosomal peptide synthetase (iPKS/NRPS). This machinery produces a universal PoTeM biosynthetic precursor that contains a tetramic acid moiety connected to two unsaturated polyene side chains. The enormous structural and hence functional diversity of PoTeMs is enabled by pathway-specific tailoring enzymes, particularly cyclization-catalyzing oxidases that process the polyene chains to form distinct ring systems, and further modifying enzymes.
View Article and Find Full Text PDFBioconjug Chem
January 2025
Department of Chemistry, Organic Chemistry Section, Jadavpur University, Kolkata 700032, India.
Herein, a water-soluble, ultrabright, near-infrared (NIR) fluorescent, mechanically interlocked molecules (MIMs)-peptide bioconjugate is designed with dual targeting capabilities. Cancer cell surface overexpressed αβ integrin targeting two RGDS tetrapeptide residues is tethered at the macrocycle of MIMs-peptide bioconjugate via Cu(I)-catalyzed click chemistry on the Wang resin, and mitochondria targeting lipophilic cationic TPP functionality is conjugated at the axle dye. Living carcinoma cell selective active targeting, subsequently cell penetration, mitochondrial imaging, including the ultrastructure of cristae, and real-time tracking of malignant mitochondria by MIMs-peptide bioconjugate (RGDS)-Mito-MIMs-TPP are established by stimulated emission depletion (STED) super-resolved fluorescence microscopy.
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