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The CART (cocaine- and amphetamine-regulated transcript) peptide is an anorexigenic neuropeptide that acts in the hypothalamus. The receptor and the mechanism of action of this peptide are still unknown. In our previous study, we showed that the CART peptide binds specifically to PC12 rat pheochromocytoma cells in both the native and differentiated into neuronal phenotype. Two biologically active forms, CART(55-102) and CART(61-102), with equal biological activity, contain three disulfide bridges. To clarify the importance of each of these disulfide bridges in maintaining the biological activity of CART(61-102), an Ala scan at particular S-S bridges forming cysteines was performed, and analogs with only one or two disulfide bridges were synthesized. In this study, a stabilized CART(61-102) analog with norleucine instead of methionine at position 67 was also prepared and was found to bind to PC12 cells with an anorexigenic potency similar to that of CART(61-102). The binding study revealed that out of all analogs tested, [Ala(68,86)]CART(61-102), which contains two disulfide bridges (positions 74-94 and 88-101), preserved a high affinity to both native PC12 cells and those that had been differentiated into neurons. In food intake and behavioral tests with mice after intracerebroventricular administration, this analog showed strong and long-lasting anorexigenic potency. Therefore, the disulfide bridge between cysteines 68 and 86 in CART(61-102) can be omitted without a loss of biological activity, but the preservation of two other disulfide bridges and the full-length peptide are essential for biological activity.
- MeSH
- anorektika chemie farmakologie MeSH
- buňky PC12 MeSH
- cystin chemie MeSH
- kompetitivní vazba MeSH
- krysa rodu rattus MeSH
- lokomoce účinky léků MeSH
- myši inbrední C57BL MeSH
- myši MeSH
- nocicepce účinky léků MeSH
- peptidové fragmenty chemie farmakologie MeSH
- přijímání potravy účinky léků MeSH
- proteiny nervové tkáně chemie farmakologie MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- mužské pohlaví MeSH
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Insulin is a peptide responsible for regulating the metabolic homeostasis of the organism; it elicits its effects through binding to the transmembrane insulin receptor (IR). Insulin mimetics with agonistic or antagonistic effects toward the receptor are an exciting field of research and could find applications in treating diabetes or malignant diseases. We prepared five variants of a previously reported 20-amino acid insulin-mimicking peptide. These peptides differ from each other by the structure of the covalent bridge connecting positions 11 and 18. In addition to the peptide with a disulfide bridge, a derivative with a dicarba bridge and three derivatives with a 1,2,3-triazole differing from each other by the presence of sulfur or oxygen in their staples were prepared. The strongest binding to IR was exhibited by the peptide with a disulfide bridge. All other derivatives only weakly bound to IR, and a relationship between increasing bridge length and lower binding affinity can be inferred. Despite their nanomolar affinities, none of the prepared peptide mimetics was able to activate the insulin receptor even at high concentrations, but all mimetics were able to inhibit insulin-induced receptor activation. However, the receptor remained approximately 30% active even at the highest concentration of the agents; thus, the agents behave as partial antagonists. An interesting observation is that these mimetic peptides do not antagonize insulin action in proportion to their binding affinities. The compounds characterized in this study show that it is possible to modulate the functional properties of insulin receptor peptide ligands using disulfide mimetics.
- MeSH
- disulfidy chemie MeSH
- inzulin * metabolismus MeSH
- peptidy chemie MeSH
- receptor inzulinu * MeSH
- Publikační typ
- časopisecké články MeSH
Numerous antibody-drug conjugate (ADC) linker technologies exist for the synthesis of ADCs with drug-to-antibody ratios (DARs) being an even integer (typically 2, 4 or 8). However, ADCs with odd-integer DARs are significantly harder to synthesise. Here, we report the synthesis of ADCs loaded with a single warhead, using TetraDVP linkers which simultaneously re-bridge all four interchain disulfides of an IgG1 antibody.
- MeSH
- antitumorózní látky * MeSH
- disulfidy MeSH
- imunokonjugáty * MeSH
- indikátory a reagencie MeSH
- Publikační typ
- časopisecké články MeSH
The antimicrobial 40-amino-acid-peptide lucifensin was synthesized by native chemical ligation (NCL) using N-acylbenzimidazolinone (Nbz) as a linker group. NCL is a method in which a peptide bond between two discreet peptide chains is created. This method has been applied to the synthesis of long peptides and proteins when solid-phase synthesis is imcompatible. Two models of ligation were developed: [15+25] Ala-Cys and [19+21] His-Cys. The [19+21] His-Cys method gives lower yield because of the lower stability of 18-peptide-His-Nbz-CONH2 peptide, as suggested by density functional theory calculation. Acetamidomethyl-deprotection and subsequent oxidation of the ligated linear lucifensin gave a mixture of lucifensin isomers, which differed in the location of their disulfide bridges only. The dominant isomer showed unnatural pairing of cysteines [C1-6], [C3-5], and [C2-4], which limits its ability to form α-helical structure. The activity of isomeric lucifensin toward Bacillus subtilis, Staphylococcus aureus, and Micrococcus luteus was lower than that of the natural lucifensin. The desired product native lucifensin was prepared from this isomer using a one-pot reduction with dithiotreitol and subsequent air oxidation in slightly alkaline medium.
- MeSH
- antiinfekční látky * chemická syntéza chemie farmakologie MeSH
- defensiny * chemická syntéza chemie farmakologie MeSH
- grampozitivní bakterie růst a vývoj MeSH
- kationické antimikrobiální peptidy * chemická syntéza chemie farmakologie MeSH
- sekundární struktura proteinů MeSH
- Publikační typ
- časopisecké články MeSH
