Structure of the human ATP synthase.

Area of Science:

• Biochemistry
• Molecular Biology
• Structural Biology

Background:

• Adenosine triphosphate (ATP) is the primary energy currency in cells.
• The F 1F o-ATP synthase enzyme complex is responsible for ATP production.
• The precise molecular mechanism of human ATP synthase function remained largely unknown.

Purpose of the Study:

• To elucidate the molecular mechanism of human ATP synthase.
• To visualize the key rotational states and substates of the enzyme.
• To understand how structural features facilitate ATP synthesis and proton transfer.

Main Methods:

• Cryo-electron microscopy (cryo-EM) was employed to capture high-resolution structures.
• Three main rotational states and one substate of human ATP synthase were visualized.
• Structural analysis focused on subunit interactions and conformational changes.

Main Results:

• Snapshots revealed ADP release coinciding with the F 1 subunit's open conformation.
• The symmetry mismatch between F 1 and F o motors is accommodated by complex torsional flexing, particularly of the gamma subunit.
• Water molecules in half-channels suggest proton transfer via a Grotthuss mechanism.
• Clinically relevant mutations were localized to subunit interfaces, destabilizing the complex.

Conclusions:

• The study provides unprecedented structural insights into human ATP synthase function.
• Mechanisms for ADP coordination, proton translocation, and inter-motor communication were elucidated.
• Structural mapping of mutations offers a basis for understanding associated pathologies and developing therapeutic strategies.