. Author manuscript; available in PMC: 2010 Jan 13.

Published in final edited form as: Biochemistry. 2009 Jan 13;48(1):59–73. doi: 10.1021/bi8016087

Table 5.

Multi-Shell EXAFS Curve-Fitting Results for Biferrous DFsc, DFscY51L, and DFscE11D^a.

Sample		R (Å)	σ² × 10⁵ (Å²)	ΔE₀	F^c
DFsc	2 Fe–O/N^b	2.03	380	−5.9	0.241
	3 Fe–O/N	2.16	690
	1 Fe–C/O	2.55	470
	2 Fe–C	3.00	430
	4 Fe–N–C^d	3.20	430^e
	2 Fe–C	3.60	320
	2 Fe–C	3.78	440
	5 Fe–C	4.15	560
	10 Fe–N/C–C/N/O^f	4.35	560^e

DFscY51L	2 Fe–O/N	2.03	530	−6.2	0.191
	3 Fe–O/N	2.13	810
	1 Fe–C/O	2.55	190
	2 Fe–C	3.00	670
	4 Fe–N–C^d	3.30	670^e
	2 Fe–C	3.61	430
	2 Fe–C	3.78	410
	5 Fe–C	4.17	670
	10 Fe–N/C–C/N/O^f	4.35	670^e

DFscE11D	2 Fe–O/N	2.00	530	−4.8	0.194
	3 Fe–O/N	2.13	790
	1 Fe–C/O	2.54	380
	2 Fe–C	3.02	780
	4 Fe–N–C^d	3.31	780^e
	2 Fe–C	3.63	470
	2 Fe–C	3.79	710
	3 Fe–C	4.05	1130
	6 Fe–N/C–C/N/O^f	4.36	1130^e

All fits were performed over the k range of 2-15 Å^-1. The estimated uncertainty in R is ± 0.02 Å for the first shell and ± 0.05 Å for outer shells; the uncertainty in N is ~25%.

Scatterers differing by Z ± 1 are not distinguishable in an EXAFS fit. The first element in a pair indicates the type of atom used to model the backscattered wave in the FEFF calculation.

The goodness of the fit is defined as F = [Σ(k⁶(χ_exptl – χ_calcd)²)/(Σk⁶χ_exptl²)]^½.

Modeled as the Fe-N-C path of 128° of an imidazole ring.

The σ² values for multiple-scattering paths were restricted to those of the corresponding single-scattering paths.

Modeled as the Fe-N-C path of 158° of an imidazole ring.