Table 2.

Results of Mössbauer and NRVS spectroscopy on the [4Fe-4S]²⁺ cluster [33,38]. The Mössbauer spectra were recorded at T = 77 K and B = 0 T. The ΔE_Q and δ values of the HMBPP-bound IspH are found in parentheses.

	ΔEQ [mm s−1]	δ [mm s−1]	Oxidation State and Coordination
Component 1 (50%)	1.21 (1.33)	0.42 (0.42)	Tetrahedrally coordinated Fe2.5+, mixed valence iron pairs, 3 S2− and 1 Cys ligand
Component 2 (25%)	0.89 (0.92)	0.37 (0.38)	Tetrahedrally coordinated high-spin Fe3+, 3 S2− and 1 Cys ligand
Component 3 (25%)	1.97 (1.00)	0.89 (0.64)	Hexa-coordinated high-spin Fe2+, 3 S2− and 3 H2O (tetrahedrally coordinated, 3 S2− and OHHMBPP)