title: The nature of the di-iron site in the bacterioferritin from Desulfovibrio desulfuricans.
abstract: The first crystal structure of a native di-iron center in an iron-storage protein (bacterio)ferritin is reported. The protein, isolated from the anaerobic bacterium Desulfovibrio desulfuricans, has the unique property of having Fe-coproporphyrin III as its heme cofactor. The three-dimensional structure of this bacterioferritin was determined in three distinct catalytic/redox states by X-ray crystallography (at 1.95, 2.05 and 2.35 A resolution), corresponding to different intermediates of the di-iron ferroxidase site. Conformational changes associated with these intermediates support the idea of a route for iron entry into the protein shell through a pore that passes through the di-iron center. Molecular surface and electrostatic potential calculations also suggest the presence of another ion channel, distant from the channels at the three- and four-fold axes proposed as points of entry for the iron atoms.
authors.affiliation: Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. República, EAN, Apartado 127, 2781-901 Oeiras, Portugal.
authors.forename: Sofia
authors.initials: S
authors.lastname: Macedo
authors.forename: Célia V
authors.initials: CV
authors.lastname: Romão
authors.forename: Edward
authors.initials: E
authors.lastname: Mitchell
authors.forename: Pedro M
authors.initials: PM
authors.lastname: Matias
authors.forename: Ming Y
authors.initials: MY
authors.lastname: Liu
authors.forename: António V
authors.initials: AV
authors.lastname: Xavier
authors.forename: Jean
authors.initials: J
authors.lastname: LeGall
authors.forename: Miguel
authors.initials: M
authors.lastname: Teixeira
authors.forename: Peter
authors.initials: P
authors.lastname: Lindley
authors.forename: Maria A
authors.initials: MA
authors.lastname: Carrondo
mesh_terms: D001426:Bacterial Proteins; D001665:Binding Sites; D002570:Ceruloplasmin / Q000737:chemistry; D018360:Crystallography, X-Ray; D003573:Cytochrome b Group / Q000737:chemistry*; D003901:Desulfovibrio / Q000737:chemistry; D005293:Ferritins / Q000737:chemistry*; D006418:Heme / Q000737:chemistry; D007473:Ion Channels / Q000737:chemistry; D007501:Iron / Q000737:chemistry; D008958:Models, Molecular; D010084:Oxidation-Reduction; D011487:Protein Conformation; D020836:Protein Structure, Quaternary; D021122:Protein Subunits; D055672:Static Electricity
chemical_list: D001426:Bacterial Proteins; D003573:Cytochrome b Group; D007473:Ion Channels; D021122:Protein Subunits; D006418:Heme; D005293:Ferritins; C018032:bacterioferritin; D007501:Iron; D002570:Ceruloplasmin