A structural approach to understanding the iron-binding properties of phylogenetically different frataxins
Φόρτωση...
Ημερομηνία
Συγγραφείς
Adinolfi, S.
Trifuoggi, M.
Politou, A. S.
Martin, S.
Pastore, A.
Τίτλος Εφημερίδας
Περιοδικό ISSN
Τίτλος τόμου
Εκδότης
Περίληψη
Τύπος
Είδος δημοσίευσης σε συνέδριο
Είδος περιοδικού
peer-reviewed
Είδος εκπαιδευτικού υλικού
Όνομα συνεδρίου
Όνομα περιοδικού
Hum Mol Genet
Όνομα βιβλίου
Σειρά βιβλίου
Έκδοση βιβλίου
Συμπληρωματικός/δευτερεύων τίτλος
Περιγραφή
Friedreich's ataxia (FRDA), an autosomal recessive cardio- and neurodegenerative disease, is caused by low expression of frataxin, a small mitochondrial protein, encoded in the nucleus. At the biochemical level, the lack of frataxin leads to dysregulation of mitochondrial iron homeostasis and oxidative damage, which eventually causes neuronal death. It is, however, still unclear whether frataxin is directly involved in iron binding, since the yeast orthologue, but not the human protein, has been shown to form large aggregates in the presence of large iron excess. We have compared the properties of three proteins from the frataxin family--the bacterial CyaY from Escherichia coli, the yeast Yfh1 and human frataxin--as representative of organisms of increasing complexity. We show that the three proteins have the same fold but different thermal stabilities and iron-binding properties. While human frataxin has no tendency to bind iron, CyaY forms iron-promoted aggregates with a behaviour similar to that of yeast frataxin. However, aggregation can be competed by chelator agents or by ionic strength. At physiological salt conditions, almost no aggregation is observed. The design of mutants produced to identify the protein surface involved in iron-promoted aggregation allows us to demonstrate that the process is mediated by a negatively charged surface ridge. Mutation of three of these residues is sufficient to convert CyaY in a protein with properties similar to those of human frataxin. On the other hand, mutation of the exposed surface of the beta sheet, which contains most of the conserved residues, does not affect aggregation, suggesting that iron binding is a non-conserved part of a more complex cellular function of frataxins.
Περιγραφή
Λέξεις-κλειδιά
Amino Acid Sequence, Bacterial Proteins/chemistry/genetics/metabolism, Drug Stability, Escherichia coli/genetics/metabolism, Escherichia coli Proteins/chemistry/genetics/metabolism, Friedreich Ataxia/genetics/metabolism, Humans, Iron/metabolism, Iron-Binding Proteins/*chemistry/genetics/*metabolism, Kinetics, Models, Molecular, Molecular Sequence Data, Molecular Structure, Mutagenesis, Site-Directed, Phylogeny, Protein Binding, Protein Conformation, Protein Folding, Recombinant Proteins/chemistry/genetics/metabolism, Saccharomyces cerevisiae Proteins/chemistry/genetics/metabolism, Sequence Homology, Amino Acid
Θεματική κατηγορία
Παραπομπή
Σύνδεσμος
http://www.ncbi.nlm.nih.gov/pubmed/12140189
http://hmg.oxfordjournals.org/content/11/16/1865.full.pdf
http://hmg.oxfordjournals.org/content/11/16/1865.full.pdf
Γλώσσα
en
Εκδίδον τμήμα/τομέας
Όνομα επιβλέποντος
Εξεταστική επιτροπή
Γενική Περιγραφή / Σχόλια
Ίδρυμα και Σχολή/Τμήμα του υποβάλλοντος
Πανεπιστήμιο Ιωαννίνων. Σχολή Επιστημών Υγείας. Τμήμα Ιατρικής