N-Methylation of the peptide amide bond has proven to be a powerful strategy to fine-tune the conformation and properties of peptides. In this context and for the first time, we show that N-methylation can also be used to control the copper(ii) coordination properties of peptides and stabilize at high pH values the copper(ii) species lacking amidate coordination. Namely, we have prepared a derivative of the O-Asp peptide where the copper(ii) coordinating amino acids, i.e. Asp and His residues, were N-methylated (O NMe -Asp). A combined study using potentiometric and spectroscopic (UV-Vis, CD, EPR and NMR) techniques indicates the formation of the wanted major species, [CuH(O NMe -Asp)] 2+ , where copper(ii) is bound to His4(Nϵ), His7(Nϵ), His9(Nϵ) and Asp2(COO - ). With respect to the parent non-methylated O-Asp peptide, [CuH(O NMe -Asp)] 2+ is stable at higher pH values but has lower affinity for copper(ii). Additionally, electrochemical studies reveal a Cu(ii) Cu(i) redox process with a larger cathodic and anodic peak separation. Species containing copper(ii) coordinating amidates were not observed for this O NMe -Asp peptide.
|Titolo:||The role of methylation in the copper(ii) coordination properties of a His-containing decapeptide|
|Citazione:||Hautier, A., Carvalho, T., Valensin, D., Simaan, A.j., Faure, B., Mateus, P., et al. (2019). The role of methylation in the copper(ii) coordination properties of a His-containing decapeptide. DALTON TRANSACTIONS, 48(5), 1859-1870.|
|Appare nelle tipologie:||1.1 Articolo in rivista|
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