Table 2. Free energies for proton translocation through the cytoplasmic and periplasmic water wires and neighboring water molecules (bulk)*.

			Z (Å)	Free energy (kJ/mol)
(bulk)	Peripl. water wire	wat1	14.7	0.0
		wat2	12.7	8.7
		wat3	10.7	15.0
		wat4	8.3	14.4
		wat5	6.1	7.5
D160		wat6	5.4	11.0
		wat7	3.2	14.4
		wat8	0.6	18.5
H168
	cytopl. water wire	wat9	−0.4	17.3
		wat10	−0.8	14.4
		wat11	−3.2	12.1
H318		wat12	−5.1	13.8

*The vertical coordinate z was calculated relative to the position of the sidechain of H168. Positions of the sidechains of D160, H168 and H318 with respect to the periplasmic and cytoplasmic water wires are indicated in the left column.