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Effects of Fe2+/Fe3+ Binding to Human Frataxin and Its D122Y Variant, as Revealed by Site-Directed Spin Labeling (SDSL) EPR Complemented by Fluorescence and Circular Dichroism Spectroscopies.
Doni, Davide; Passerini, Leonardo; Audran, Gérard; Marque, Sylvain R A; Schulz, Marvin; Santos, Javier; Costantini, Paola; Bortolus, Marco; Carbonera, Donatella.
Afiliação
  • Doni D; Department of Biology, University of Padova, Viale G. Colombo 3, 35131 Padova, Italy.
  • Passerini L; Department of Chemical Sciences, University of Padova, Via F. Marzolo 1, 35131 Padova, Italy.
  • Audran G; Institut de Chimie Radicalaire, Aix Marseille Universitè, CNRS, ICR, UMR 7273, Case 551, Ave Escadrille Normandie Niemen, CEDEX 20, 13397 Marseille, France.
  • Marque SRA; Institut de Chimie Radicalaire, Aix Marseille Universitè, CNRS, ICR, UMR 7273, Case 551, Ave Escadrille Normandie Niemen, CEDEX 20, 13397 Marseille, France.
  • Schulz M; Institut de Chimie Radicalaire, Aix Marseille Universitè, CNRS, ICR, UMR 7273, Case 551, Ave Escadrille Normandie Niemen, CEDEX 20, 13397 Marseille, France.
  • Santos J; Departamento de Química Biológica, Instituto de Biociencias, Biotecnología y Biomedicina (iB3-UBA), Facultad de Ciencia Exactas y Naturales, Universidad de Buenos Aires, Intendente Güiraldes 2160-Ciudad Universitaria, 1428EGA CONICET, Godoy Cruz 2290, Buenos Aires C1425FQB, Argentina.
  • Costantini P; Instituto de Química y Fisicoquímica Biológicas Dr. Alejandro Paladini, Universidad de Buenos Aires, CONICET, Junín 956, Buenos Aires 1113AAD, Argentina.
  • Bortolus M; Department of Biology, University of Padova, Viale G. Colombo 3, 35131 Padova, Italy.
  • Carbonera D; Department of Chemical Sciences, University of Padova, Via F. Marzolo 1, 35131 Padova, Italy.
Int J Mol Sci ; 21(24)2020 Dec 17.
Article em En | MEDLINE | ID: mdl-33348670
ABSTRACT
Frataxin is a highly conserved protein whose deficiency results in the neurodegenerative disease Friederich's ataxia. Frataxin's actual physiological function has been debated for a long time without reaching a general agreement; however, it is commonly accepted that the protein is involved in the biosynthetic iron-sulphur cluster (ISC) machinery, and several authors have pointed out that it also participates in iron homeostasis. In this work, we use site-directed spin labeling coupled to electron paramagnetic resonance (SDSL EPR) to add new information on the effects of ferric and ferrous iron binding on the properties of human frataxin in vitro. Using SDSL EPR and relating the results to fluorescence experiments commonly performed to study iron binding to FXN, we produced evidence that ferric iron causes reversible aggregation without preferred interfaces in a concentration-dependent fashion, starting at relatively low concentrations (micromolar range), whereas ferrous iron binds without inducing aggregation. Moreover, our experiments show that the ferrous binding does not lead to changes of protein conformation. The data reported in this study reveal that the currently reported binding stoichiometries should be taken with caution. The use of a spin label resistant to reduction, as well as the comparison of the binding effect of Fe2+ in wild type and in the pathological D122Y variant of frataxin, allowed us to characterize the Fe2+ binding properties of different protein sites and highlight the effect of the D122Y substitution on the surrounding residues. We suggest that both Fe2+ and Fe3+ might play a relevant role in the context of the proposed FXN physiological functions.
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Texto completo: 1 Base de dados: MEDLINE Assunto principal: Marcadores de Spin / Compostos Férricos / Compostos Ferrosos / Dicroísmo Circular / Proteínas de Ligação ao Ferro / Ferro Limite: Humans Idioma: En Ano de publicação: 2020 Tipo de documento: Article

Texto completo: 1 Base de dados: MEDLINE Assunto principal: Marcadores de Spin / Compostos Férricos / Compostos Ferrosos / Dicroísmo Circular / Proteínas de Ligação ao Ferro / Ferro Limite: Humans Idioma: En Ano de publicação: 2020 Tipo de documento: Article