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The Ca2+ as cofactor of mitochondrial H+-translocating F1FO-ATP(hydrol)ase
  • Salvatore Nesci,
  • Alessandra Pagliarani
Salvatore Nesci
Alma Mater Studiorum Università di Bologna
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Alessandra Pagliarani
Alma Mater Studiorum University of Bologna
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Abstract

The mitochondrial F1FO-ATPase in the presence of the natural cofactor Mg2+ acts as the enzyme of life by synthesizing ATP, but it can also hydrolyze ATP to pump H+. Interestingly, Mg2+ can be replaced by Ca2+, but only to sustain ATP hydrolysis and not ATP synthesis. When Ca2+ inserts in F1, the torque generation built by the chemomechanical coupling between F1 and the rotating central stalk was reported as unable to drive the transmembrane H+ flux within FO. However, the failed H+ translocation is not consistent with the oligomycin-sensitivity of the Ca2+-dependent F1FO-ATP(hydrol)ase. New enzyme roles in mitochondrial energy transduction are suggested by recent advances. Accordingly, the structural F1FO-ATPase distortion driven by ATP hydrolysis sustained by Ca2+ is consistent with the permeability transition pore signal propagation pathway. The Ca2+-activated F1FO-ATPase, by forming the pore, may contribute to dissipate the transmembrane H+ gradient created by the same enzyme complex.

Peer review status:ACCEPTED

08 Oct 2020Submitted to PROTEINS: Structure, Function, and Bioinformatics
09 Oct 2020Submission Checks Completed
09 Oct 2020Assigned to Editor
20 Oct 2020Reviewer(s) Assigned
06 Nov 2020Review(s) Completed, Editorial Evaluation Pending
25 Nov 2020Editorial Decision: Revise Major
03 Dec 20201st Revision Received
04 Dec 2020Submission Checks Completed
04 Dec 2020Assigned to Editor
04 Dec 2020Reviewer(s) Assigned
10 Dec 2020Review(s) Completed, Editorial Evaluation Pending
27 Dec 2020Editorial Decision: Accept