Table 5. Comparison of K_d Values for Studied and Biological Ligands for Fe(II), Zn(II), and Mn(II)^a.

ligand	Fe(II)	Mn(II)	Zn(II)	ref
P2	4.75 × 10–7	7.02 × 10–7	6.31 × 10–8	this work
E. coli Fur	1.2 × 10–6	2.4 × 10–5	1.4 × 10–10	(78)
S. pyogenes MtsA	4.3 × 10–6			(79)
B. subtilis MntR		(0.2−2) × 10–6		(80)
Y. pestis YfeA		1.78 × 10–8	6.6 × 10–9	(81)
T. pallidum TroA		7.1 × 10–9	2.25 × 10–8	(82)
D. radiodurans MntH		1.9 × 10–4		(83)
Synechocystis ZnuA			7.3 × 10–9	(84)

^aK_d values calculated for our systems as at pH 7.0.