Table 2. LC-MS analysis of (apo)flavodoxin.

Species	Label in Figure 8	Expected mass (Da)	Measured mass (Da)	Δ(mass) (Da)
Apoflavodoxin	M	19531.8	19533±1.5	+1.2 Da
Apoflavodoxin +1 O	MO	19547.8	Not observed	-
Apoflavodoxin +2 O	MO2	19563.8	19565±2	+1.2 Da
Apoflavodoxin +3 O	MO3	19579.8	19582±2	+2.2 Da
Apoflavodoxin + NBD	M-NBD	19695.9	19697±2	+1.1 Da
Apoflavodoxin +1 O + NBD	MO-NBD	19711.9	19713±2	+1.1 Da
Apoflavodoxin dimer	D	39063.6	39066±5	+2.4 Da

Monomeric protein species are labelled M. Molecular masses of NBD-Cl and NBD are 199.6 and 164.1 Da, respectively. Expected mass and measured mass are average masses.