. Author manuscript; available in PMC: 2017 Sep 1.

Published in final edited form as: Biochim Biophys Acta. 2016 Jun 16;1857(9):1594–1606. doi: 10.1016/j.bbabio.2016.06.005

Table 3.

DFT relative energies (kcal/mol) for proton transfer in Fe_a3³⁺-(O-OH)⁻-Cu_B²⁺-Y237⁻ DNC models and proton uptake from the N-side of the membrane (at pH = 7), with Q being the total charge of the cluster model. See Table 1 and Figure 1 for the protonation states of Asp372, PRAa₃ and His376 in the different intermediates. In state B₂, His376 is doubly protonated and both Asp372 and PRAa₃ are deprotonated. The prime indicates δ-protonation in place of ε-protonation of His376. See Figure 3 for a representation of the cluster model.

State	Q	E
		PW91-D3	OLYP-D3	B3LYP-D3//PW91-D3
A’ + (H⁺,pH=7)	0	0.0	0.0	0.0
B + (H⁺,pH=7)	0	9.8	8.8	13.4
B₂ + (H⁺,pH=7)	0	10.5	6.8	8.3
C’	1	14.2	9.3	4.9
D	1	–5.8	–5.5	-13.3