Table 1.

Dissociation constants (K_d) of YxeB-L142-6×His and YxeB-S142-6×His

Ligand	Kd (nM)
	YxeB-L142-6×His	YxeB-S142-6×His
DFO	NC	35.9 (0.0056*)
FO	38.8 (0.0032*)	29.1 (0.0054*)
Cr-DFO	69.0 (0.0036*)	98.9 (0.0054*)
DFch	NC	23.0 (0.0113*)
Fch	43.0 (0.0184*)	29.3 (0.0096*)

NC is not calculated using Hyperquad (18) because the protein fluorescence increased (Fig. S1).

^*Number indicates SD calculated by Hyperquad (18).