- Names
-
- S. Morante
- S. Botticelli
- R. Chiaraluce
- V. Consalvi
- G. La Penna
- L. Novak
- A. Pasquo
- M. Petrosino
- O. Proux
- G. Rossi
- G. Salina
- F. Stellato
- Title
- Metal Ion Binding in Wild-Type and Mutated Frataxin: A Stability Study
- Abstract
- This work studies the stability of wild-type frataxin and some of its variants found in cancer tissues upon Co2+ binding. Although the physiologically involved metal ion in the frataxin enzymatic activity is Fe2+, as it is customarily done, Co2+ is most often used in experiments because Fe2+ is extremely unstable owing to the fast oxidation reaction Fe2+ → Fe3+. Protein stability is monitored following the conformational changes induced by Co2+ binding as measured by circular dichroism, fluorescence spectroscopy, and melting temperature measurements. The stability ranking among the wild-type frataxin and its variants obtained in this way is confirmed by a detailed comparative analysis of the XAS spectra of the metal-protein complex at the Co K-edge. In particular, a fit to the EXAFS region of the spectrum allows positively identifying the frataxin acidic ridge as the most likely location of the metal-binding sites. Furthermore, we can explain the surprising feature emerging from a detailed analysis of the XANES region of the spectrum, showing that the longer 81-210 frataxin fragment has a smaller propensity for Co2+ binding than the shorter 90-210 one. This fact is explained by the peculiar role of the N-terminal disordered tail in modulating the protein ability to interact with the metal.
- Keywords
- spectroscopy
- Content
- sample, experimental physics, materials sciences, spectral data
- Year
- 2022
- Journal
- Frontiers in Molecular Biosciences
- Volume
- 9
- Pages
- 1 - 13
- Document type
- article
- Publication state
- published
- Doi
- 10.3389/fmolb.2022.878017
- Identifiers
-
- bibcode: 10.3389/fmolb.2022.878017