EPR study of the mixed-valent diiron sites in mouse and herpes simplex virus ribonucleotide reductases. Effect of the tyrosyl radical on structure and reactivity of the diferric center

Researchers have investigated the mixed-valent states of the recombinant mammalian (mouse) and HSV1 R2 proteins. An EPR study looked at the diiron sites in mouse and HSV1 R2 proteins obtained by reduction in frozen solution at 77 K with mobile electrons produced by gamma-radiolysis. It was established that gamma-irradiation of mouse and HSV1 R2 proteins in a water-glycerol glass at 77 K leads to transient mixed-valent diiron intermediates in quite high yields.