FIG. 2.

EPR analysis of recombinant Fdx3. EPR spectrum of reduced Fdx3 was recorded at 10 K, with a modulation frequency of 100 kHz and a modulation amplitude of 1 mT. The protein concentration was 170 μM in 20 mM Tris-HCl (pH 7.5) containing 50 mM NaCl. It was fully reduced with an excess (5 reducing equivalents) of sodium dithionite (1 mM) under anaerobic conditions (monitored by optical absorption). The spin concentration was estimated to be 250 μM by integration of the EPR signal and comparison with a reference.