Table 3.

Fe-Fe and Fe-ligand Bond Lengths (Å), Broken-Symmetry State Energies (E, eV), Fe Net Spin Populations (NSP), and Mössbauer Properties (Isomer shifts δ, Quadrupole Splittings ΔE_Q, mm s⁻¹, and η) of the Resting State [Fe₄S₄(S_γ-Cys)₄]²⁻ Cluster in Wild-Type Pa-APSR with Substrate Binding: Comparison between Calculations and Experiments (Exp).

	Calculated Chain-B with APS			Exp a
	Fe1↓Fe2↓Fe3↑Fe4↑	Fe1↑Fe2↓Fe3↓Fe4↑	Fe1↑Fe2↓Fe3↑Fe4↓
Fe1-Fe2	2.741	2.718	2.669	2.7
Fe1-Fe3	2.683	2.690	2.717	2.7
Fe1-Fe4	2.727	2.813	2.742	2.7
Fe2-Fe3	2.732	2.863	2.750	2.7
Fe2-Fe4	2.680	2.708	2.792	2.7
Fe3-Fe4	2.728	2.670	2.678	2.7
Fe1-S1	2.304	2.205	2.303	2.3
Fe1-S2	2.333	2.308	2.227	2.3
Fe1-S3	2.209	2.310	2.314	2.3
Fe2-S1	2.313	2.308	2.221	2.3
Fe2-S2	2.267	2.183	2.274	2.2
Fe2-S4	2.247	2.343	2.338	2.3
Fe3-S1	2.178	2.267	2.271	2.2
Fe3-S3	2.310	2.222	2.308	2.2
Fe3-S4	2.305	2.293	2.217	2.2
Fe4-S2	2.193	2.273	2.285	2.3
Fe4-S3	2.290	2.284	2.202	2.3
Fe4-S4	2.310	2.230	2.302	2.3
Fe1-Sγ-Cys140	2.304	2.329	2.326	2.3
Fe2-Sγ-Cys139	2.293	2.325	2.315	2.3
Fe3-Sγ-Cys228	2.290	2.306	2.306	2.3
Fe4-Sγ-Cys231	2.257	2.289	2.276	2.3
E	−1446.545	−1446.291	−1446.501
NSP(Fe1, Fe2, Fe3, Fe4)	(−3.13, −3.11, 3.12, 3.07)	(3.14, −3.16, −3.12, 3.13)	(3.14, −3.14, 3.17, −3.13)
δ(Fe1, Fe2, Fe3, Fe4)	(0.45, 0.45, 0.43, 0.42)	(0.46, 0.45, 0.43, 0.43)	(0.47, 0.46, 0.44, 0.43)	0.45 18
Average δ	0.44	0.44	0.45
ΔEQ(Fe1, Fe2, Fe3, Fe4)	(1.08, 0.95, 0.79, −1.03)	(0.87, 1.24, 1.15, 0.70)	(0.85, 1.04, 0.87, 1.23)	1.12 18
Average |ΔEQ|	0.96	0.99	1.00
η(Fe1, Fe2, Fe3, Fe4)	(0.33, 0.65, 0.53, 0.88)	(0.78, 0.34, 0.29, 0.62)	(0.89, 0.64, 0.42, 0.33)

^aThe crystal structure was at 2.7 Å resolution, PDB code: 2GOY.¹³ Distances are taken from chain-B with substrate binding.