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Critical evaluation of the one- versus the two-channel model for the operation of the ATP synthase’s Fo motor

2000; Elsevier BV; Volume: 1459; Issue: 2-3 Linguagem: Inglês

10.1016/s0005-2728(00)00190-0

1879-2650

Peter Dimroth, Ulrich Matthey, Georg Kaim,

Fuel Cells and Related Materials

The mechanism of converting an electrochemical gradient of protons or Na(+) ions across the membrane into rotational torque by the F(o) motor of the ATP synthase has been described by a two-channel model or by a one-channel model. Experimental evidence obtained with the F(o) motor from the Propionigenium modestum ATP synthase is described which is in accordance with the one-channel model, but not with the two-channel model. This evidence includes the ATP-dependent occlusion of one (22)Na(+) per ATP synthase with a mutated Na(+)-impermeable a subunit or the Na(+)(in)/(22)Na(+)(out) exchange which is not affected by modifying part of the c subunit sites with dicyclohexylcarbodiimide.