Table 1. Values of the nuclear parameters and contributions for the five components issued from simulations of the spectra^*.

Species	δ(mm s−1)	ΔEQ(mm s−1)	Γ(mm s−1)†	% in control cell samples		% in induced ISCA cells
ISCA1
HS FeII	1.36	3.13	0.43	25	39	30	43
HS FeII	1.18	2.97	0.43	14		13
[Fe4S4]2+ and LS FeII haem	0.45	1.15	0.40	15	61	12	34
FeIII NP	0.48	0.61	0.57	45		22
[Fe2S2]2+‡	0.27	0.50	0.28	<2	<4	12	24
	0.28	0.68	0.28	<2		12
ISCA2
HS FeII	1.36	3.13	0.52	36	57	41	54
HS FeII	1.18	2.97	0.52	21		13
[Fe4S4]2+ and LS FeII haem	0.45	1.15	0.41	13	43	10	26
FeIII NP	0.48	0.61	0.60	30		16
[Fe2S2]2+‡	0.27	0.50	0.32	<2	<4	10	20
	0.28	0.68	0.32	<2		10

^*Shown in Fig. 1c Italic numbers indicate the overall contributions of HS Fe^II species, of the two components with 0.4–0.5 mm s⁻¹ isomer shift values (Fe₄S₄ clusters, LS ferrous haems and Fe^III NP), and of the two sites of the Fe₂S₂ clusters. Uncertainties are ±0.02 mm s⁻¹ on δ, ΔE_Q and Γ and ±3 on the percentage of each site.

^†The linewidth for HS Fe^II components were constrained to be equal. The same holds for the two sites of the [Fe₂S₂]²⁺ clusters.

^‡Isomer shift and quadrupole splitting values are those published for the [Fe₂S₂]²⁺ cluster of ^NifIscA (ref. ⁵³) and were fixed. The two sites were assumed to contribute in a 1:1 ratio.