A new isolation procedure for Kalata polypeptides from the tropical plant Oldenlandia affinis DC is described. Fractions were screened by thin-layer chromatography, and Van Urk positive fractions were tested for oxytocic activity in estrogenized rat uteri. By using this procedure, we were able to isolate and characterize three macrocyclic polypeptides with uterine activity. Their amino acid sequence and biological effects have been analyzed, and their NMR spectra were compared with those of the earlier ones. All three peptides showed hemolytic activity on human blood, and were tested for antibiotic effect against E. coli, Staphylococcus aureus, and Hemophilus influenzae.
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http://dx.doi.org/10.1002/cbdv.200890184 | DOI Listing |
Methods Enzymol
October 2023
School of Chemistry, Cardiff University, Park Place, Cardiff, United Kingdom. Electronic address:
A variant originated from Oldenlandia affinis asparaginyl ligase, OaAEP1-C247A, has emerged as an ideal tool for protein labeling. However, its preparation was laborious and time-consuming. It is recombinantly produced as a zymogen, requiring acid activation and four chromatographic steps; despite these extensive steps, the catalytically active enzyme exhibited only moderate purity.
View Article and Find Full Text PDFJ Nat Prod
May 2023
Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, Queensland 4072, Australia.
Cyclotides are a unique family of stable and cyclic mini-proteins found in plants that have nematicidal and anthelmintic activities. They are distributed across the Rubiaceae, Violaceae, Fabaceae, Cucurbitaceae, and Solanaceae plant families, where they are posited to act as protective agents against pests. In this study, we tested the nematicidal properties of extracts from four major cyclotide-producing plants, , , , and , against the free-living model nematode .
View Article and Find Full Text PDFBioconjug Chem
March 2023
Department of Chemical Biology, Faculty of Biotechnology, University of Wrocław, F. Joliot-Curie 14a, Wrocław 50-383, Poland.
Among all approaches used for the semisynthesis of natural or chemically modified products, enzyme-assisted ligation is among the most promising and dynamically developing approaches. Applying an efficient C247A mutant of plant ligase OaAEP1 and solid-phase peptide synthesis chemistry, we present the chemoenzymatic synthesis of a complete sequence of the cysteine-rich and metal-binding cyanobacterial metallothionein Synechococcus metallothionein A (SmtA). Zn(II) and Cd(II) binding to the newly synthesized SmtA showed identical properties to the protein expressed in .
View Article and Find Full Text PDFSci Rep
June 2022
Center for Physiology and Pharmacology, Medical University of Vienna, 1090, Vienna, Austria.
The cholecystokinin-2 receptor (CCKR) is a G protein-coupled receptor (GPCR) that is expressed in peripheral tissues and the central nervous system and constitutes a promising target for drug development in several diseases, such as gastrointestinal cancer. The search for ligands of this receptor over the past years mainly resulted in the discovery of a set of distinct synthetic small molecule chemicals. Here, we carried out a pharmacological screening of cyclotide-containing plant extracts using HEK293 cells transiently-expressing mouse CCKR, and inositol phosphate (IP1) production as a readout.
View Article and Find Full Text PDFPhytochemistry
March 2022
Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, Queensland, 4072, Australia. Electronic address:
Cyclotides are a class of ribosomally-synthesized plant peptides that function in plants as a defense against insects and fungal pathogens. Their unique structure comprises a cyclized peptide backbone threaded by three disulfide bonds, that imparts structural stability, a desirable quality for peptide-based therapeutics or insecticides. Producing these peptides synthetically is challenging due to the amount of chemical waste produced and inefficiency of folding certain cyclotides.
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