Electrochemical studies of binary and ternary copper(II) complexes with α-factor analogues

Ufnalska, Iwona; Wawrzyniak, Urszula E.; Bossak-Ahmad, Karolina; Bal, Wojciech; Wróblewski, Wojciech

doi:10.1016/j.jelechem.2020.114003

Cited by 6 publications

(13 citation statements)

References 32 publications

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“…This is in accord with the presence of the 3 + 1N coordination of Cu(II) in the ternary complex, which stabilizes Cu(III) better. 45 The largest shifts in electrochemical responses occurred for Cu(II)-Aβ 5–9 -Im and Cu(II)-Aβ 5–12 -Im in relation to the binary complexes. In contrast, a weaker interaction between Cu(II)-Aβ 5–16 and imidazole due to the presence of the autoternary complex resulted in a smaller change in redox activity of this chelate.…”

Section: Resultsmentioning

confidence: 94%

Aβ_5–x Peptides: N-Terminal Truncation Yields Tunable Cu(II) Complexes

et al. 2020

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The Aβ 5– x peptides ( x = 38, 40, 42) are minor Aβ species in normal brains but elevated upon the application of inhibitors of Aβ processing enzymes. They are interesting from the point of view of coordination chemistry for the presence of an Arg-His metal binding sequence at their N-terminus capable of forming a 3-nitrogen (3N) three-coordinate chelate system. Similar sequences in other bioactive peptides were shown to bind Cu(II) ions in biological systems. Therefore, we investigated Cu(II) complex formation and reactivity of a series of truncated Aβ 5– x peptide models comprising the metal binding site: Aβ 5–9 , Aβ 5–12 , Aβ 5–12 Y10F, and Aβ 5–16 . Using CD and UV–vis spectroscopies and potentiometry, we found that all peptides coordinated the Cu(II) ion with substantial affinities higher than 3 × 10 12 M –1 at pH 7.4 for Aβ 5–9 and Aβ 5–12 . This affinity was elevated 3-fold in Aβ 5–16 by the formation of the internal macrochelate with the fourth coordination site occupied by the imidazole nitrogen of the His13 or His14 residue. A much higher boost of affinity could be achieved in Aβ 5–9 and Aβ 5–12 by adding appropriate amounts of the external imidazole ligand. The 3N Cu-Aβ 5– x complexes could be irreversibly reduced to Cu(I) at about −0.6 V vs Ag/AgCl and oxidized to Cu(III) at about 1.2 V vs Ag/AgCl. The internal or external imidazole coordination to the 3N core resulted in a slight destabilization of the Cu(I) state and stabilization of the Cu(III) state. Taken together these results indicate that Aβ 5– x peptides, which bind Cu(II) ions much more strongly than Aβ 1– x peptides and only slightly weaker than Aβ 4– x peptides could interfere with Cu(II) handling by these peptides, adding to copper dyshomeostasis in Alzheimer brains.

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Section: Resultsmentioning

confidence: 94%

Aβ_5–x Peptides: N-Terminal Truncation Yields Tunable Cu(II) Complexes

et al. 2020

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“…The yeast behavior is also similar to the electrochemical response of tryptophan amino acid. Ufnalska et al (2020) proposed that the electrochemical signal of yeast is due to tryptophan residues presented in peptides involved in yeast reproduction. Other authors also showed the relationship between cell growth in fermentation processes and tryptophan ( Álvarez-Fernández et al, 2019 ; Dei Cas et al, 2021 ; Fernández-Cruz et al, 2017 ).…”

Section: Resultsmentioning

confidence: 99%

Electrochemical determination of Saccharomyces cerevisiae sp using glassy carbon electrodes modified with oxidized multi-walled carbon nanotubes dispersed in water –Nafion®

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Hoyos-Arbeláez

et al. 2022

Current Research in Food Science

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“…This profile of electrochemical changes is consistent with the spectroscopic results discussed above. Since the cathodic signal shift toward less negative potentials was observed previously as a consequence of ternary complex formation by 3N species, 65 such temporary fluctuations in the reduction peak position along with a significant current decrease fit well with the transient GSH-Cu(II)GHK species. A longer-term signal stabilization at a potential slightly higher than for Cu(II)GHK correlates with the accumulation of GHK-Cu(II)GHK, accompanying the loss of Cu(II) due to reduction, as explained above.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Intermediate Cu(II)-Thiolate Species in the Reduction of Cu(II)GHK by Glutathione: A Handy Chelate for Biological Cu(II) Reduction

et al. 2021

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Gly-His-Lys (GHK) is a tripeptide present in the human bloodstream that exhibits a number of biological functions. Its activity is attributed to the copper-complexed form, Cu(II)GHK. Little is known, however, about the molecular aspects of the mechanism of its action. Here, we examined the reaction of Cu(II)GHK with reduced glutathione (GSH), which is the strongest reductant naturally occurring in human plasma. Spectroscopic techniques (UV–vis, CD, EPR, and NMR) and cyclic voltammetry helped unravel the reaction mechanism. The impact of temperature, GSH concentration, oxygen access, and the presence of ternary ligands on the reaction were explored. The transient GSH-Cu(II)GHK complex was found to be an important reaction intermediate. The kinetic and redox properties of this complex, including tuning of the reduction rate by ternary ligands, suggest that it may provide a missing link in copper trafficking as a precursor of Cu(I) ions, for example, for their acquisition by the CTR1 cellular copper transporter.

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Electrochemical studies of binary and ternary copper(II) complexes with α-factor analogues

Cited by 6 publications

References 32 publications

Aβ_5–x Peptides: N-Terminal Truncation Yields Tunable Cu(II) Complexes

Aβ_5–x Peptides: N-Terminal Truncation Yields Tunable Cu(II) Complexes

Electrochemical determination of Saccharomyces cerevisiae sp using glassy carbon electrodes modified with oxidized multi-walled carbon nanotubes dispersed in water –Nafion®

Intermediate Cu(II)-Thiolate Species in the Reduction of Cu(II)GHK by Glutathione: A Handy Chelate for Biological Cu(II) Reduction

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Electrochemical studies of binary and ternary copper(II) complexes with α-factor analogues

Cited by 6 publications

References 32 publications

Aβ5–x Peptides: N-Terminal Truncation Yields Tunable Cu(II) Complexes

Aβ5–x Peptides: N-Terminal Truncation Yields Tunable Cu(II) Complexes

Electrochemical determination of Saccharomyces cerevisiae sp using glassy carbon electrodes modified with oxidized multi-walled carbon nanotubes dispersed in water –Nafion®

Intermediate Cu(II)-Thiolate Species in the Reduction of Cu(II)GHK by Glutathione: A Handy Chelate for Biological Cu(II) Reduction

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Aβ_5–x Peptides: N-Terminal Truncation Yields Tunable Cu(II) Complexes

Aβ_5–x Peptides: N-Terminal Truncation Yields Tunable Cu(II) Complexes