Water-Gated Proton Transfer Dynamics in Respiratory Complex I

Area of Science:

• Biochemistry
• Molecular Biology
• Bioenergetics

Background:

• Respiratory complex I is vital for cellular energy production, converting redox energy into a proton gradient.
• Despite recent structural data, the precise mechanism of complex I function remains elusive.
• Understanding complex I is key to comprehending mitochondrial function and disease.

Purpose of the Study:

• To elucidate the mechanism of proton translocation in respiratory complex I.
• To identify the molecular components controlling protonation dynamics within the enzyme.
• To explore the link between complex I function and mitochondrial disease.

Main Methods:

• Integration of large-scale quantum and classical molecular simulations.
• Application of site-directed mutagenesis techniques.
• Utilization of biophysical experimental approaches.

Main Results:

• Identified control of protonation dynamics by buried ion-pairs and water molecules.
• Established evolutionary conserved long-range coupling elements within complex I.
• Proposed an energy-efficient electrostatic wave mechanism for proton-electron coupling across the membrane domain.

Conclusions:

• Complex I utilizes an electrostatic wave for efficient, long-range proton-electron coupling (PCET).
• Specific conformational states of internal components regulate proton transfer dynamics.
• Dysfunction in this PCET machinery is implicated in the development of mitochondrial diseases.