Harnessing free radicals: formation and function of the tyrosyl radical in ribonucleotide reductase.

Deals with class-I ribonucleotide reductases (RNR), for which the Escherichia coli enzyme serves as a prototype. Formation of the diiron(III)-tyrosyl-radical cofactor of class-I RNRs; Other diiron(III) requiring proteins; Function of the tyrosyl radical; Importance of tyrosine radicals or modified tyrosine radicals in metabolism.