We report here the first rapid parallel production of bioactive folded cyclotides by using Fmoc-based solid-phase peptide synthesis in combination with a "tea-bag" approach. Using this approach, we efficiently synthesized 15 analogues of the CXCR4 antagonist cyclotide MCo-CVX-5c. Cyclotides were synthesized in a single-pot, cyclization/folding reaction in the presence of reduced glutathione. Natively folded cyclotides were quickly purified from the cyclization/folding crude mixture by activated thiol Sepharose-based chromatography. The different folded cyclotide analogues were then tested for their ability to inhibit the CXCR4 receptor in a cell-based assay. The results indicated that this approach can be used for the efficient chemical synthesis of libraries of cyclotides with improved biological properties that can be easily interfaced with solution or cell-based assays for rapid screening.
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http://dx.doi.org/10.1002/cbic.201402691 | DOI Listing |
RSC Chem Biol
June 2024
Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland Brisbane Queensland Australia
Cyclotides are a diverse class of plant-derived cyclic, disulfide-rich peptides with a unique cyclic cystine knot topology. Their remarkable structural stability and resistance to proteolytic degradation can lead to improved pharmacokinetics and oral activity as well as selectivity and high enzymatic stability. Thus, cyclotides have emerged as powerful scaffold molecules for designing peptide-based therapeutics.
View Article and Find Full Text PDFChem Sci
May 2024
School of Chemistry and Chemical Engineering, South China University of Technology Guangzhou 510640 China
Native chemical ligation (NCL) has been playing an increasingly important role in chemical protein synthesis (CPS). More efficient ligation methods that circumvent the requirement of a peptidyl thioester and thiol additive-which allow the following desulfurization or refolding in one pot-are urgently needed for the synthesis of more complex protein targets and in large quantities. Herein, we discover that the weak acyl donor peptidyl -acyl pyrazole can be activated by azole reagents like 3-methylpyrazole or imidazole to facilitate its ligation directly with an N-terminal cysteine peptide.
View Article and Find Full Text PDFChemMedChem
July 2024
Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, Qld, 4072, Australia.
Cyclotides are cyclic peptides that are promising scaffolds for the design of drug candidates and chemical tools. However, despite there being hundreds of reported cyclotides, drug design studies have commonly focussed on a select few prototypic examples. Here, we explored whether ancestral sequence reconstruction could be used to generate new cyclotides for further optimization.
View Article and Find Full Text PDFJ Biol Chem
April 2024
Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, Queensland, Australia. Electronic address:
Cyclotides are plant-derived peptides characterized by a head-to-tail cyclic backbone and a cystine knot motif comprised of three disulfide bonds. Formation of this motif via in vitro oxidative folding can be challenging and can result in misfolded isomers with nonnative disulfide connectivities. Here, we investigated the effect of β-turn nucleation on cyclotide oxidative folding.
View Article and Find Full Text PDFJ Biol Chem
April 2022
Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, QLD, Australia. Electronic address:
Cyclotides have a wide range of bioactivities relevant for agricultural and pharmaceutical applications. This large family of naturally occurring macrocyclic peptides is divided into three subfamilies, with the bracelet subfamily being the largest and comprising the most potent cyclotides reported to date. However, attempts to harness the natural bioactivities of bracelet cyclotides and engineer-optimized analogs have been hindered by a lack of understanding of the structural and functional role of their constituent residues, which has been challenging because bracelet cyclotides are difficult to produce synthetically.
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