scholarly journals Structural basis of proton translocation and force generation in mitochondrial ATP synthase

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Niklas Klusch ◽  
Bonnie J Murphy ◽  
Deryck J Mills ◽  
Özkan Yildiz ◽  
Werner Kühlbrandt
Keyword(s):  
Atp Synthase ◽  
Proton Translocation ◽  
Potential Gradient ◽  
Structural Basis ◽  
Ring Rotation ◽  
Mitochondrial Atp Synthase ◽  
The Matrix ◽  
A Subunit ◽  
Proton Leakage ◽  
Rotary Catalysis

ATP synthases produce ATP by rotary catalysis, powered by the electrochemical proton gradient across the membrane. Understanding this fundamental process requires an atomic model of the proton pathway. We determined the structure of an intact mitochondrial ATP synthase dimer by electron cryo-microscopy at near-atomic resolution. Charged and polar residues of the a-subunit stator define two aqueous channels, each spanning one half of the membrane. Passing through a conserved membrane-intrinsic helix hairpin, the lumenal channel protonates an acidic glutamate in the c-ring rotor. Upon ring rotation, the protonated glutamate encounters the matrix channel and deprotonates. An arginine between the two channels prevents proton leakage. The steep potential gradient over the sub-nm inter-channel distance exerts a force on the deprotonated glutamate, resulting in net directional rotation.

scholarly journals Structure and conformational states of the bovine mitochondrial ATP synthase by cryo-EM

eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Anna Zhou ◽  
Alexis Rohou ◽  
Daniel G Schep ◽  
John V Bason ◽  
Martin G Montgomery ◽  
...  
Keyword(s):  
Atp Synthase ◽  
Catalytic Mechanism ◽  
Proton Translocation ◽  
Atp Synthesis ◽  
Bioinformatic Analysis ◽  
Mitochondrial Atp Synthase ◽  
A Subunit ◽  
Classification Of Images ◽  
Atp Synthases

Adenosine triphosphate (ATP), the chemical energy currency of biology, is synthesized in eukaryotic cells primarily by the mitochondrial ATP synthase. ATP synthases operate by a rotary catalytic mechanism where proton translocation through the membrane-inserted FO region is coupled to ATP synthesis in the catalytic F1 region via rotation of a central rotor subcomplex. We report here single particle electron cryomicroscopy (cryo-EM) analysis of the bovine mitochondrial ATP synthase. Combining cryo-EM data with bioinformatic analysis allowed us to determine the fold of the a subunit, suggesting a proton translocation path through the FO region that involves both the a and b subunits. 3D classification of images revealed seven distinct states of the enzyme that show different modes of bending and twisting in the intact ATP synthase. Rotational fluctuations of the c8-ring within the FO region support a Brownian ratchet mechanism for proton-translocation-driven rotation in ATP synthases.

Essential arginine residue of the Fo-a subunit in FoF1-ATP synthase has a role to prevent the proton shortcut without c-ring rotation in the Fo proton channel

2010 ◽  
Vol 430 (1) ◽  
pp. 171-177 ◽  
Author(s):  
Noriyo Mitome ◽  
Sakurako Ono ◽  
Hiroki Sato ◽  
Toshiharu Suzuki ◽  
Nobuhito Sone ◽  
...  
Keyword(s):  
Atp Synthase ◽  
Proton Translocation ◽  
Critical Role ◽  
Arginine Residue ◽  
Proton Channel ◽  
Ring Rotation ◽  
A Subunit ◽  
Coupled Reactions ◽  
Single Polypeptide ◽  
Fof1 Atp Synthase

In FoF1 (FoF1-ATP synthase), proton translocation through Fo drives rotation of the oligomer ring of Fo-c subunits (c-ring) relative to Fo-a. Previous reports have indicated that a conserved arginine residue in Fo-a plays a critical role in the proton transfer at the Fo-a/c-ring interface. Indeed, we show in the present study that thermophilic FoF1s with substitution of this arginine (aR169) to other residues cannot catalyse proton-coupled reactions. However, mutants with substitution of this arginine residue by a small (glycine, alanine, valine) or acidic (glutamate) residue mediate the passive proton translocation. This translocation requires an essential carboxy group of Fo-c (cE56) since the second mutation (cE56Q) blocks the translocation. Rotation of the c-ring is not necessary because the same arginine mutants of the ‘rotation-impossible’ (c10-a)FoF1, in which the c-ring and Fo-a are fused to a single polypeptide, also exhibits the passive proton translocation. The mutant (aR169G/Q217R), in which the arginine residue is transferred to putatively the same topological position in the Fo-a structure, can block the passive proton translocation. Thus the conserved arginine residue in Fo-a ensures proton-coupled c-ring rotation by preventing a futile proton shortcut.

scholarly journals Structure and conformational states of the bovine mitochondrial ATP synthase by cryo-EM

2015 ◽  
Author(s):  
Anna Zhou ◽  
Alexis Rohou ◽  
Daniel G Schep ◽  
John V Bason ◽  
Martin G Montgomery ◽  
...  
Keyword(s):  
Atp Synthase ◽  
Catalytic Mechanism ◽  
Proton Translocation ◽  
Atp Synthesis ◽  
Bioinformatic Analysis ◽  
Mitochondrial Atp Synthase ◽  
A Subunit ◽  
Classification Of Images ◽  
Atp Synthases

Adenosine triphosphate (ATP), the chemical energy currency of biology, is synthesized in eukaryotic cells primarily by the mitochondrial ATP synthase. ATP synthases operate by a rotary catalytic mechanism where proton translocation through the membrane-inserted FO region is coupled to ATP synthesis in the catalytic F1 region via rotation of a central rotor subcomplex. We report here single particle electron cryomicroscopy (cryo-EM) analysis of the bovine mitochondrial ATP synthase. Combining cryo-EM data with bioinformatic analysis allowed us to determine the fold of the a subunit, suggesting a proton translocation path through the FO region that involves both the a and b subunits. 3D classification of images revealed seven distinct states of the enzyme that show different modes of bending and twisting in the intact ATP synthase. Rotational fluctuations of the c8-ring within the FO region support a Brownian ratchet mechanism for proton-translocation driven rotation in ATP synthases.

The a subunit asymmetry dictates the two opposite rotation directions in the synthesis and hydrolysis of ATP by the mitochondrial ATP synthase

2015 ◽  
Vol 84 (1) ◽  
pp. 53-57 ◽  
Author(s):  
Salvatore Nesci ◽  
Fabiana Trombetti ◽  
Vittoria Ventrella ◽  
Alessandra Pagliarani
Keyword(s):  
Atp Synthase ◽  
Mitochondrial Atp Synthase ◽  
A Subunit ◽  
Hydrolysis Of

scholarly journals Rotary substates of mitochondrial ATP synthase reveal the basis of flexible F1-Fo coupling

2019 ◽  
Author(s):  
Bonnie J. Murphy ◽  
Niklas Klusch ◽  
Julian D. Langer ◽  
Deryck J. Mills ◽  
Özkan Yildiz ◽  
...  
Keyword(s):  
Atp Synthase ◽  
Metal Ion ◽  
De Novo ◽  
Atp Synthesis ◽  
Joint Movement ◽  
Access Channel ◽  
Subunit Interface ◽  
Ring Rotation ◽  
Mitochondrial Atp Synthase ◽  
Ordered Water

F1Fo-ATP synthases play a central role in cellular metabolism, making the energy of the proton-motive force across a membrane available for a large number of energy-consuming processes. We determined the single-particle cryo-EM structure of active dimeric ATP synthase from mitochondria of Polytomella sp. at 2.7- 2.8 Å resolution. Separation of 13 well-defined rotary substates by 3D classification provides a detailed picture of the molecular motions that accompany c-ring rotation and result in ATP synthesis. Crucially, the F1 head rotates along with the central stalk and c-ring rotor for the first ~30° of each 120° primary rotary step. The joint movement facilitates flexible coupling of the stoichiometrically mismatched F1 and Fo subcomplexes. Flexibility is mediated primarily by the interdomain hinge of the conserved OSCP subunit, a well-established target of physiologically important inhibitors. Our maps provide atomic detail of the c-ring/a-subunit interface in the membrane, where protonation and deprotonation of c-ring cGlu111 drives rotary catalysis. An essential histidine residue in the lumenal proton access channel binds a strong non-peptide density assigned to a metal ion that may facilitate c-ring protonation, as its coordination geometry changes with c-ring rotation. We resolve ordered water molecules in the proton access and release channels and at the gating aArg239 that is critical in all rotary ATPases. We identify the previously unknown ASA10 subunit and present complete de novo atomic models of subunits ASA1-10, which make up the two interlinked peripheral stalks that stabilize the Polytomella ATP synthase dimer.

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