InterPro domain: IPR012348

The R2 protein of ribonucleotide reductase catalyses the reduction of all four ribonucleotides to deoxyribonucleotides for use in DNA synthesis. This catalysis involves generating and storing a tyrosyl radical, which is essential for ribonucleotide reduction. The crystal structure consists of a core of four helices in a closed bundle with a left-handed twist and one crossover connection, and a bimetal-ion centre in the middle of the bundle [ 1 ].

This entry represents proteins that are structurally related to the R2 protein of class I ribonucleotide reductase, including the alpha and beta subunits of methane monooxygenase, and delta 9-stearoyl-acyl carrier protein desaturase [ 2 ].

1. The three-dimensional structure of mammalian ribonucleotide reductase protein R2 reveals a more-accessible iron-radical site than Escherichia coli R2. J. Mol. Biol. 262, 706-20
2. Di-iron-carboxylate proteins. Curr. Opin. Struct. Biol. 5, 758-66