Description
Experimental Technique/Method:X-RAY DIFFRACTION
Resolution:1.99
Classification:OXIDOREDUCTASE
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
DOI:10.2210/pdb3n3a/pdb
Abstract:
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.
Resolution:1.99
Classification:OXIDOREDUCTASE
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
DOI:10.2210/pdb3n3a/pdb
Abstract:
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 available | 2010 |
|---|---|
| Publisher | RCSB-PDB |