3N38: Ribonucleotide Reductase Nrdf From Escherichia Coli Soaked With Ferrous Ions

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.
PDB ID: 3N38Download
MMDB ID: 84194
PDB Deposition Date: 2010/5/19
Updated in MMDB: 2010/11
Experimental Method:
x-ray diffraction
Resolution: 1.9  Å
Source Organism:
Similar Structures:
Biological Unit for 3N38: dimeric; determined by author and by software (PISA)
Molecular Components in 3N38
Label Count Molecule
Proteins (2 molecules)
Ribonucleoside-diphosphate Reductase 2 Subunit Beta(Gene symbol: nrdF)
Molecule annotation
Chemicals (4 molecules)
* Click molecule labels to explore molecular sequence information.

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