3N3A : Ribonucleotide Reductase Dimanganese(II)-NrdF from Escherichia coli in Complex with Reduced NrdI

  • Amie K. Boal (Contributor)
  • Joseph A. Cotruvo (Contributor)
  • Joanne Stubbe (Contributor)
  • Amy C Rosenzweig (Contributor)



Experimental Technique/Method:X-RAY DIFFRACTION
Release Date:2010-08-18
Deposition Date:2010-05-19
Revision Date:2011-07-13
Molecular Weight:108515.39
Macromolecule Type:Protein
Residue Count:944
Atom Site Count:6693

The class Ib ribonucleotide reductase of Escherichia coli can initiate reduction of nucleotides to deoxynucleotides with either a Mn(III)2-tyrosyl radical (Y•) or a Fe(III)2-Y• cofactor in the NrdF subunit. Whereas Fe(III)2-Y• can self-assemble from Fe(II)2-NrdF and O2, activation of Mn(II)2-NrdF requires a reduced flavoprotein, NrdI, proposed to form the oxidant for cofactor assembly by reduction of O2. The crystal structures reported here of E. coli Mn(II)2-NrdF and Fe(II)2-NrdF reveal different coordination environments, suggesting distinct initial binding sites for the oxidants during cofactor activation. In the structures of Mn(II)2-NrdF in complex with reduced and oxidized NrdI, a continuous channel connects the NrdI flavin cofactor to the NrdF Mn(II)2 active site. Crystallographic detection of a putative peroxide in this channel supports the proposed mechanism of Mn(III)2-Y• cofactor assembly.
Date made available2010

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