Figure 5.

Tyrosyl radical reduction in mouse R2 RNR protein by the proligand HL¹, and complexes 1 and 3, in the absence and in the presence of a reductant. The samples contained 20 μM mR2 in 50 mM Hepes buffer, pH 7.60/100 mM KCl, and 20 μM HL¹, 1 or 3 in 1% (v/v) DMSO/H₂O, and 2 mM dithiothreiotol (DTT). Error bars are standard deviations from two independent experiments. Inset: 30 K EPR spectrum of tyrosyl radical in mR2 (microwave power 3.2 mW, modulation amplitude 5 G).