TABLE 1.

Redox, spectroscopic, and functional properties of the EhFdp1 variants

EvarianthFdp1	E°(FMNox → FMNsq FMNsq → FMNred)	EPR g values	E°, (Fe3+Fe3+ → Fe3+Fe2+ Fe3+Fe2+ → Fe2+Fe2+)	kobs, NO reaction	NO Reductase activity	Vmax O2
	mV		mV	s−1	μm NO s−1 μm protein	s−1
WT	−55–140	1.95, 1.77	+ 170 + 132	0.12 ± 0.02	1.7 ± 0.4	400 ± 30
K53D	−58–114	1.94, 1.78	+ 160 + 45	0.20 ± 0.01	3.4 ± 1.0	667 ± 29
Y271S	−33–130	1.89, 1.86, 1.75	+ 165 + 59	0.94 ± 0.03	3.1 ± 0.9	1020 ± 12
K53D/Y271S	−43–127	1.87, 1.75	+ 112 + 4	2.1 ± 0.1	6.0 ± 1.0	627 ± 41