Tuning the coordination properties of multi-histidine peptides by using a tripodal scaffold: solution chemical study and catechol oxidase mimicking
| Autor: | Katalin Selmeczi, Zsuzsanna Darula, Ágnes Dancs, Ferenc Matyuska, Nóra V. May, Tamás Gajda, Attila Szorcsik, Tibor Páli |
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| Rok vydání: | 2017 |
| Předmět: |
Tertiary amine
biology 010405 organic chemistry Stereochemistry Chemistry Metal ions in aqueous solution General Chemistry 010402 general chemistry 01 natural sciences Combinatorial chemistry Catalysis 0104 chemical sciences Metal Catalytic cycle visual_art Materials Chemistry visual_art.visual_art_medium biology.protein Chelation Catechol oxidase Histidine |
| Zdroj: | New Journal of Chemistry. 41:808-823 |
| ISSN: | 1369-9261 1144-0546 |
| DOI: | 10.1039/c6nj03126a |
| Popis: | Two new tripodal peptides containing non-protected N-terminal (L1, tren3his) and C-terminal (L2, nta3his) histidines have been synthesized in order to combine the structuring effect of tripodal scaffolds and the strong metal binding properties of histidine moieties. In the present work the copper(II) complexes of these ligands have been studied by combined pH-metric, UV-Vis, CD, EPR and MS methods. At a 1 : 1 metal-to-ligand ratio the two ligands behave as the corresponding dipeptides containing N/C-terminal histidines, but above pH 9 the participation of the tertiary amine in the fused chelate rings results in unique binding modes in the case of both ligands. Besides, the formation of oligonuclear complexes also confirms the positive influence of tripodal platforms on metal coordination, and provides the potential to be efficient functional models of oxidase enzymes. Accordingly, the oligonuclear complexes of both ligands exhibit considerable catecholase-like activity. The oxidation of 3,5-di-tert-butyl-catechol proceeds with the participation of separated Cu2+ centers in the presence of L1 complexes. However, the proximity of the two metal ions in the dinuclear complexes of L2 allows their cooperation along the catalytic cycle. Substrate binding modes, effects of reactants, intermediate and side product formation have also been studied, allowing us to propose a plausible catalytic mechanism for each copper(II)–ligand system. |
| Databáze: | OpenAIRE |
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