title: Effects of Fe(III) binding to the nucleotide-independent site of F1-ATPase: enzyme thermostability and response to activating anions.
abstract: Mitochondrial F1-ATPase was induced in different conformations by binding of specific ligands, such as nucleotides. Then, Fourier transform infrared spectroscopy (FT-IR) and kinetic analyses were run to evaluate the structural and functional effects of Fe(III) binding to the nucleotide-independent site. Binding of one equivalent of Fe(III) induced a localised stabilising effect on the F1-ATPase structure destabilised by a high concentration of NaCl, through rearrangements of the ionic network essential for the maintenance of enzyme tertiary and/or quaternary structure. Concomitantly, a lower response of ATPase activity to activating anions was observed. Both FT-IR and kinetic data were in accordance with the hypothesis of the Fe(III) site location near one of the catalytic sites, i.e. at the alpha/beta subunit interface.
authors.affiliation: Dipartimento di Scienze e Tecnologie Biomediche, Università di Udine, Italy. scontessi@makek.dstb.uniud.it
authors.forename: S
authors.initials: S
authors.lastname: Contessi
authors.forename: F
authors.initials: F
authors.lastname: Tanfani
authors.forename: A
authors.initials: A
authors.lastname: Scirè
authors.forename: I
authors.initials: I
authors.lastname: Mavelli
authors.forename: G
authors.initials: G
authors.lastname: Lippe
mesh_terms: D000838:Anions; D001665:Binding Sites; D004789:Enzyme Activation; D004795:Enzyme Stability; D005290:Ferric Compounds / Q000378:metabolism*; D006358:Hot Temperature; D007700:Kinetics; D006180:Proton-Translocating ATPases / Q000378:metabolism*; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D000838:Anions; D005290:Ferric Compounds; D006180:Proton-Translocating ATPases