Alternative proton binding mode in ATP synthases

Area of Science:

• Biochemistry
• Structural Biology
• Molecular Biophysics

Background:

• ATP synthases are crucial rotary motors converting ion gradients into ATP.
• Existing models focus on protonation/deprotonation of c-ring amino acids for proton translocation.
• This mechanism is central to energy conversion in all living organisms.

Purpose of the Study:

• To present an alternative mechanism for proton binding in ATP synthases.
• To explore the role of hydronium ion coordination in proton translocation.
• To provide a new perspective on the function of these essential enzymes.

Main Methods:

• Review of existing biochemical data.
• Analysis of structural considerations of the c-ring.
• Integration of recent findings from other proton-translocating proteins.

Main Results:

• Evidence supports two distinct proton binding modes in the c-ring of H+-ATP synthases.
• Hydronium ion coordination is proposed as a significant factor in proton translocation.
• This coordination mechanism may be a general principle in proton-translocating proteins.

Conclusions:

• The traditional protonation/deprotonation model may be incomplete.
• Hydronium ion coordination offers a revised understanding of ATP synthase function.
• This revised mechanism could have broader implications for understanding membrane protein function.