So in the first step, what happens is we have this hydrophilic half channel is open to the matrix of the mitochondria. And at the center of that half channel is this aspartate 61 residue that bears a negative charge. And so the proton will move from a high concentration through this half channel and it will bind onto that aspartate 61 residue found at the center of this C subunit that lies along this half channel. Now, once that movement actually takes place, once the movement takes place and the H plus binds onto this aspartate residue, we form aspartic acid. And aspartic acid is not as hydrophilic as aspartate. And so because aspartic acid is actually more hydrophobic, that aspartic acid that is formed when the H plus ion binds until aspartate 61 will want to move into the hydrophobic region of the inner membrane of the mitochondria.