Investigations of the EPR parameters for three copper complexes

Guo, Jia-Xing; Wu, Shao-Yi; Luo, Ying-Jie; Fan, Yi-Mei; Zhu, Qihe

doi:10.1016/j.comptc.2020.112952

Cited by 6 publications

(3 citation statements)

References 46 publications

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“…The EPR results show that the ∆g // (g // - g e ) (e.g., ~0.348 for GMP/Cu 2+ , ~0.379 for Fmoc-K/GTP/Cu 2+ and 0.389 for Fmoc-K/GDP/Cu 2+ ) of the Cu 2+ complexes containing GDP or GTP, or single nucleotide components, were higher than other complexes containing T2Cu-mimietic sites. The higher ∆g values indicate a lower crystal-field strength 42 as a result of the phosphate groups replacing the π-acid type ligands, such as histidines in copper enzymes and nucleobases in our complexes, as the ligand coordinating to Cu 2+ 16 , and may also indicate that phosphate-Cu 2+ binding was not dominant in the Fmoc-modified amino acids/monophosphate nucleotides (e.g., GMP) hybrids. Cu-Cu distances of <4.0 Å were also found in Fmoc-K/UMP/Cu 2+ (Supplementary Fig.…”

Section: Resultsmentioning

confidence: 94%

A supramolecular metalloenzyme possessing robust oxidase-mimetic catalytic function

Liu

et al. 2023

Nat Commun

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Enzymes fold into unique three-dimensional structures to distribute their reactive amino acid residues, but environmental changes can disrupt their essential folding and lead to irreversible activity loss. The de novo synthesis of enzyme-like active sites is challenging due to the difficulty of replicating the spatial arrangement of functional groups. Here, we present a supramolecular mimetic enzyme formed by self-assembling nucleotides with fluorenylmethyloxycarbonyl (Fmoc)-modified amino acids and copper. This catalyst exhibits catalytic functions akin those of copper cluster-dependent oxidases, and catalytic performance surpasses to date-reported artificial complexes. Our experimental and theoretical results reveal the crucial role of periodic arrangement of amino acid components, enabled by fluorenyl stacking, in forming oxidase-mimetic copper clusters. Nucleotides provide coordination atoms that enhance copper activity by facilitating the formation of a copper-peroxide intermediate. The catalyst shows thermophilic behavior, remaining active up to 95 °C in an aqueous environment. These findings may aid the design of advanced biomimetic catalysts and offer insights into primordial redox enzymes.

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Section: Resultsmentioning

confidence: 94%

A supramolecular metalloenzyme possessing robust oxidase-mimetic catalytic function

Liu

et al. 2023

Nat Commun

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“…Based on the values determined using simulation, the g iso parameter was calculated and plotted as function of the ligand binding site (Figure S3A, Table 1). It mirrors the level of covalence in the Cu II complexes, [33] with higher g iso corresponding to weaker covalence. As previously documented and expected, the addition of sulfur atoms in the coordination sphere of Cu II causes a decrease in both parameters due to the greater electron-donating properties of sulfur atoms than nitrogen atoms.…”

Section: Chemistry-a European Journalmentioning

confidence: 67%

Ability of Azathiacyclen Ligands To Stop Cu(Aβ)‐Induced Production of Reactive Oxygen Species: [3N1S] Is the Right Donor Set

Malikidogo

Drommi

Atrián‐Blasco

et al. 2023

Chemistry A European J

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Alzheimer's disease (AD) is an incurable neurodegenerative disease that leads to the progressive and irreversible loss of mental functions. The amyloid beta (Aβ) peptide involved in the disease is responsible for the production of damaging reactive oxygen species (ROS) when bound to Cu ions. A therapeutic approach that consists of removing Cu ions from Aβ to alter this deleterious interaction is currently being developed. In this context, we report the ability of five different 12-membered thiaazacyclen ligands to capture Cu from Aβ and to redox silence it. We propose that the presence of a sole sulfur atom in the ligand increases the rate of Cu capture and removal from Aβ, while the kinetic aspect of the chelation was an issue encountered with the 4N parent ligand. The best ligand for removing Cu from Aβ and inhibiting the associated ROS production is the 1-thia-4,7,10triazacyclododecane [3N1S]. Indeed the replacement of more N by S atoms makes the corresponding Cu complexes easier to reduce and thus able to produce ROS on their own. In addition, the ligand with three sulfur atoms has a weaker affinity for Cu II than Aβ, and is thus unable to remove Cu from CuAβ.

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“…The MATLAB toolbox EasySpin was used to generate all simulated EPR spectra, to obtain the g values (both g ∥ and g ⊥ ) and A values (Figure S3 and Table S2), which are indicative of the coordination environments and the unpaired copper electrons in the d x 2– y 2 orbital that are facing the ligands directly. The g -shift Δ g (≈ g – g e ) ( g e , free electron g factor, ∼2.0023) is a common parameter used to indicate the strength of the crystal field. − Two distinct sets of EPR parameters ( g ∥ , 2.300, A ∥ , 168 × 10 –4 cm –1 ; g ∥ , 2.250, A ∥ , 187 × 10 –4 cm –1 ) were observed in the Fmoc-K/Cu 2+ complex. These parameters were associated with two Cu(II) species that possess different coordination environments.…”

Section: Resultsmentioning

confidence: 99%

Oxidase-Mimetic Nanocatalyst Based on Geometry-Dependent Biomolecular Self-Assembly

Li,

Wu,

Liu

et al. 2023

Chem. Mater.

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Investigations of the EPR parameters for three copper complexes

Cited by 6 publications

References 46 publications

A supramolecular metalloenzyme possessing robust oxidase-mimetic catalytic function

A supramolecular metalloenzyme possessing robust oxidase-mimetic catalytic function

Ability of Azathiacyclen Ligands To Stop Cu(Aβ)‐Induced Production of Reactive Oxygen Species: [3N1S] Is the Right Donor Set

Oxidase-Mimetic Nanocatalyst Based on Geometry-Dependent Biomolecular Self-Assembly

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