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. Author manuscript; available in PMC: 2013 Jul 14.
Published in final edited form as: Dalton Trans. 2012 Mar 20;41(26):7984–7993. doi: 10.1039/c2dt30147d

Table 3.

Best EXAFS fits to the NO-bound and Fe(II)–unligated states of H-NOX from Sw and Pa.a

Sw H-NOX and Pa H-NOX Fe(II)–unligated and Fe(II)–NO complexes
Sw Fe(II)–NO Pa Fe(II)–NO Sw Fe(II)–unligated Pa Fe(II)–unligated
shell r σ 2 shell r σ 2 shell r σ 2 shell r σ 2
1 Fe-NO 1.75 1.8 1 Fe-NO 1.72 5.3
4 Fe-Np 1.99 2.0 4 Fe-Np 1.98 4.0 4 Fe-Np + 1
Fe-NHis 		2.06 5.7 4 Fe-Np + 1
Fe-NHis 		2.06 5.2
8 Fe••Cα 3.02 3.0 8 Fe••Cα 3.03 2.8 8 Fe••Cα 3.11 6.6 8 Fe••Cα 3.10 3.1
16 Fe••Cα/Np 3.19 6.1 16 Fe••Cα/Np 3.20 5.6
4 Fe••Ch 3.38 3.5 4 Fe••Ch 3.41 0.55 4 Fe••Ch 3.40 2.37
8 Fe••Cβ 4.36 4.8 8 Fe••Cβ 4.37 7.1 8 Fe••Cβ 4.42 3.8 8 Fe••Cβ 4.42 3.9
16 Fe••Cβ/Np 4.39 9.6 16 Fe••Cβ/Np 4.39 14.2 16 Fe••Cβ/Np 4.45 7.6 16 Fe••Cβ/Np 4.45 7.7
F 0.342 F 0.406 F 0.301 F 0.306
ΔE0 7.65 ΔE0 6.21 ΔE0 3.88 ΔE0 3.31
a

r is in units of Å; σ2 is in units of 10−3 Å2; ΔE0 is in units of eV. All fits are to unfiltered data. F represents a goodness-of-fit parameter. Fourier transform ranges: k = 2.0 – 12.0 Å−1 (resolution = 0.157 Å) for Sw H-NOX Fe(II)–unligated; k = 2.0 – 13.0 Å−1 (resolution = 0.142 Å) for Pa H-NOX Fe(II)–unligated; k = 2.0 – 13.85 Å−1 (resolution = 0.134 Å) for Sw H-NOX Fe(II)–NO; k = 2.0 – 12.5 Å−1 (resolution = 0.150 Å) for Pa H-NOX Fe(II)–NO. Values of r for the Fe••Cα single scattering and Fe••Cα/Np multiple scattering paths were constrained to a constant difference from one another, while σ2 for the multiple scattering path was constrained to be twice that of the single scattering path. A similar constraint was placed on the Cβ and Cβ/Np combination. Inclusion of the Fe••Cα/Np multiple scattering paths was not required for fits of Fe(II)–unligated data.