Control of metallation and active cofactor assembly in the class Ia and Ib ribonucleotide reductases: diiron or dimanganese?

Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, United States; Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, United States. stubbe@mit.edu

Current opinion in chemical biology 2011 Apr

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Ribonucleotide reductases (RNRs) convert nucleotides to deoxynucleotides in all organisms. Activity of the class Ia and Ib RNRs requires a stable tyrosyl radical (Yⁱ), which can be generated by the reaction of O2 with a diferrous cluster on the β subunit to form active diferric-Yⁱ cofactor. Recent experiments have demonstrated, however, that in vivo the class Ib RNR contains an active dimanganese(III)-Yⁱ cofactor. The similar metal binding sites of the class Ia and Ib RNRs, their ability to bind both MnII and FeII, and the activity of the class Ib RNR with both diferric-Yⁱ and dimanganese(III)-Y cofactors raise the intriguing question of how the cell prevents mismetallation of these essential enzymes. The presence of the class Ib RNR in numerous pathogenic bacteria also highlights the importance of manganese for these organisms' growth and virulence. Copyright © 2010 Elsevier Ltd. All rights reserved.

Citation

JoAnne Stubbe, Joseph A Cotruvo. Control of metallation and active cofactor assembly in the class Ia and Ib ribonucleotide reductases: diiron or dimanganese? Current opinion in chemical biology. 2011 Apr;15(2):284-90