Biochemical and biophysical characterization of the selenium-binding and reducing site in Arabidopsis thaliana homologue to mammals selenium-binding protein 1. - BIG - Chimie et Biologie des Métaux (CBM) Accéder directement au contenu
Article Dans Une Revue Journal of Biological Chemistry Année : 2014

Biochemical and biophysical characterization of the selenium-binding and reducing site in Arabidopsis thaliana homologue to mammals selenium-binding protein 1.

David Cobessi
Géraldine Sarret
Vincent Forge
  • Fonction : Auteur
  • PersonId : 853643
Denis Testemale

Résumé

The function of selenium-binding protein 1 (SBP1), present in almost all organisms, has not yet been established. In mammals, SBP1 is known to bind the essential element selenium but the binding site has not been identified. In addition, the SBP family has numerous potential metal-binding sites that may play a role in detoxification pathways in plants. In Arabidopsis thaliana, AtSBP1 over-expression increases tolerance to two toxic compounds for plants, selenium and cadmium, often found as soil pollutants. For a better understanding of AtSBP1 function in detoxification mechanisms, we investigated the chelating properties of the protein toward different ligands with a focus on selenium using biochemical and biophysical techniques. Thermal shift assays together with inductively coupled plasma mass spectrometry revealed that AtSBP1 binds selenium after incubation with selenite (SeO3(2-)) with a ligand to protein molar ratio of 1:1. Isothermal titration calorimetry confirmed the 1:1 stoichiometry and revealed an unexpectedly large value of binding enthalpy suggesting a covalent bond between selenium and AtSBP1. Titration of reduced Cys residues and comparative mass spectrometry on AtSBP1 and the purified selenium-AtSBP1 complex identified Cys(21) and Cys(22) as being responsible for the binding of one selenium. These results were validated by site-directed mutagenesis. Selenium K-edge x-ray absorption near edge spectroscopy performed on the selenium-AtSBP1 complex demonstrated that AtSBP1 reduced SeO3(2-) to form a R-S-Se(II)-S-R-type complex. The capacity of AtSBP1 to bind different metals and selenium is discussed with respect to the potential function of AtSBP1 in detoxification mechanisms and selenium metabolism.
Fichier principal
Vignette du fichier
2014_Schild_Journal of Biological Chemistry_1.pdf (4.76 Mo) Télécharger le fichier
Origine : Fichiers éditeurs autorisés sur une archive ouverte
Loading...

Dates et versions

hal-01108713 , version 1 (27-05-2020)

Licence

Copyright (Tous droits réservés)

Identifiants

Citer

Florie Schild, Sylvie Kieffer-Jacquinot, Andrés Palencia, David Cobessi, Géraldine Sarret, et al.. Biochemical and biophysical characterization of the selenium-binding and reducing site in Arabidopsis thaliana homologue to mammals selenium-binding protein 1.. Journal of Biological Chemistry, 2014, 289 (46), pp.31765-31776. ⟨10.1074/jbc.M114.571208⟩. ⟨hal-01108713⟩
460 Consultations
51 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More