Table 2.

Best-fit simulation Fe XAS parameters for Fe-fIscU, FeS-fIscU and Yah1. Difference in parameters suggests the Fe-binding site in Fe-fIscU is distinct from an authentic FeS-cluster coordination site.^a

Sample	Fe-Nearest Neighbor Ligandsb				Fe•••Long Range Ligandsb				F′g
	Atomc	R(Å)d	C.N.e	σ2f	Atomc	R(Å)d	C.N.e	σ2 f
Fe – fIscU	O/N	1.99	3.0	3.78	C	3.13	1.5	3.01	0.32
	O/N	2.15	2.0	2.94
FeS-fIscU	O/N	2.03	1.5	4.37	C	4.07	2.0	2.37	0.46
	S	2.28	2.0	5.03	C	4.83	4.0	0.76
	Fe	2.72	0.5	3.84
FeS-Yah1	S	2.29	4.0	5.58					0.40
	Fe	2.71	0.75	2.36

^aYeast Fe-Isu1 and FeS-Isu1 values from EXAFS simulations, published recently¹⁵, include [Atom, R, CN, σ²] and (F′) values of: Fe-yIsu1 – [O/N, 2.01, 1.0, 1.91], [O/N, 2.14, 4.5, 3.25], [C, 3.01, 1.5, 1.14], (0.99); and FeS-yIsu1 – [O/N, 2.11, 2.5, 5.05], [S, 2.26, 1.0, 2.45], [Fe, 2.69, 0.5, 1.70], (0.69).

^bIndependent metal-ligand scattering environment

^cScattering atoms: O (Oxygen), N (Nitrogen), C (Carbon), S (Sulfur) and Fe (Iron)

^dMetal-ligand bond length

^eMetal-ligand coordination number

^fDebye-Waller factor given in Ų × 10³

^gNumber of degrees of freedom weighted mean square deviation between data and fit