The role of methylation in the copper( ii ) coordination properties of a His-containing decapeptide

Alexandre Hautier, Tiago Carvalho, Daniela Valensin, A. Jalila Simaan, Bruno Faure, Pedro Mateus, Rita Delgado, Olga Iranzo

Research output: Contribution to journalArticlepeer-review

1 Citation (Scopus)

Abstract

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.

Original languageEnglish
Pages (from-to)1859-1870
JournalDalton Transactions
Volume48
Issue number5
DOIs
Publication statusPublished - 16 Jan 2019

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