Rotors hydrophobically asymmetric

Prediction of Hydrophobically Asymmetric and Elastically Deformable Rotor and Housing... 

Above, the predicted hydrophobically asymmetric rotor was found. Furthermore, the hydrophobically asymmetric rotor associated... 

ATP binding naturally results from the hydrophobically asymmetric rotor. 

Thus the fundamental predictions of the hydrophobic elastic consilient mechanism are that the rotor would exhibit asymmetric hydrophobicity, that different arrangements of nucleotide analogues representing different states of polarity at the catalytic sites would orient the rotor, and that hydrolysis of ATP in formation of the most polar state at a catalytic site of the involved protein subunit(s) would demonstrate a near-ideal elastic deformation of the y-rotor and the protein subunit(s). Of course, such a mechanism would exhibit high efficiency and reversibility. 

The rotor that is driven by the Fo-motor comprises a single y-subunit and a small e-subunit attached to the y-subunit at a point proximal to the base of the Fo-motor. This is called the y-rotor. In the hydrophobic elastic consilient mechanism, the interactions of a hydrophobi-cally asymmetric y-rotor with the housing of the Fi-motor with different occupancy states of the catalytic sites constitute the basis for mechano-chemical transduction of the Fi-motor. 

Our perspective of the hydrophobic consilient mechanism as it would apply to ATP synthase requires that there be an asymmetric hydro-phobic rotor and that a variable apolar-polar repulsion occur between the different occupancy states of the catalytic p-subunits and the rotor. If the hydrophobic consilient mechanism is relevant, then the structure utilized in Figure 8.30 should occur with a distinctly and hydro-phobically asymmetric y-rotor. 

Prediction 1 The rotor must be hydrophobi-cally asymmetric. Because the catalytic housing of the Fi-ATPase is essentially threefold symmetric but with different occupancies in the three p-catalytic subunits, three different faces of the y-rotor are identified from the crystal structure with different occupancies of the three catalytic subunits. Indeed, the three faces are calculated to have very different Gibbs free energies for hydrophobic association, AGha, namely, -20, 0, and +9kcal/mole in order of decreasing hydrophobicity. Thus, the prediction of a rotor with hydrophobic asymmetry is strikingly borne out. Tbe order of hydrophobicity, when considered in terms of the apolar-polar repulsion between occupancy and direction of rotation, makes sense with respect to mechanism. 

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