Determination of the g-, hyperfine coupling- and zero-field splitting tensors in EPR and ENDOR using extended Matlab codes

Lund, Anders; Callens, Freddy; Sagstuen, Einar

doi:10.1016/j.jmr.2021.106956

Cited by 1 publication

(1 citation statement)

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“…In order to increase spectral resolution, a small amount of methanol (not exceeding 10%) was added to the Cu(II) complex aqueous solutions, after adjusting the pH to the desired value, to obtain a good quality glass upon freezing [69]. The ESR magnetic parameters g || and A || were extracted from the 2nd and the 3rd line to remove second order effects [70]. Some experimental spectra were simulated by the program Monoclin [71], which allows researchers to distinguish more species simultaneously present.…”

Section: Electron Spin Resonance Spectroscopy (Esr)mentioning

confidence: 99%

Peptides Derived from Angiogenin Regulate Cellular Copper Uptake

Tabbı̀

Cucci

Pinzino

et al. 2021

IJMS

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The angiogenin protein (ANG) is one of the most potent endogenous angiogenic factors. In this work we characterized by means of potentiometric, spectroscopic and voltammetric techniques, the copper complex species formed with peptide fragments derived from the N-terminal domain of the protein, encompassing the sequence 1-17 and having free amino, Ang1-17, or acetylated N-terminus group, AcAng1-17, so to explore the role of amino group in metal binding and cellular copper uptake. The obtained data show that amino group is the main copper anchoring site for Ang1-17. The affinity constant values, metal coordination geometry and complexes redox-potentials strongly depend, for both peptides, on the number of copper equivalents added. Confocal laser scanning microscope analysis on neuroblastoma cells showed that in the presence of one equivalent of copper ion, the free amino Ang1-17 increases cellular copper uptake while the acetylated AcAng1-17 strongly decreases the intracellular metal level. The activity of peptides was also compared to that of the protein normally present in the plasma (wtANG) as well as to the recombinant form (rANG) most commonly used in literature experiments. The two protein isoforms bind copper ions but with a different coordination environment. Confocal laser scanning microscope data showed that the wtANG induces a strong increase in intracellular copper compared to control while the rANG decreases the copper signal inside cells. These data demonstrate the relevance of copper complexes’ geometry to modulate peptides’ activity and show that wtANG, normally present in the plasma, can affect cellular copper uptake.

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Section: Electron Spin Resonance Spectroscopy (Esr)mentioning

confidence: 99%