title: The crystal structure of the Dps2 from Deinococcus radiodurans reveals an unusual pore profile with a non-specific metal binding site.
abstract: The crystal structure of recombinant Dps2 (DRB0092, DNA protecting protein under starved conditions) from the Gram-positive, radiation-resistant bacterium Deinococcus radiodurans has been determined in its apo and iron loaded states. Like other members of the Dps family, the bacterial DrDps2 assembles as a spherical dodecamer with an outer shell diameter of 90 A and an interior diameter of 40 A. A total of five iron sites were located in the iron loaded structure, representing the first stages of iron biomineralisation. Each subunit contains a mononuclear iron ferroxidase centre coordinated by residues highly conserved amongst the Dps family of proteins. In the structures presented, a distinct iron site is observed 6.1 A from the ferroxidase centre with a unique ligand configuration of mono coordination by the protein and no bridging ligand to the ferroxidase centre. A non-specific metallic binding site, suspected to play a regulative role in iron uptake/release from the cage, was found in a pocket located near to the external edge of the C-terminal 3-fold channel.
authors.affiliation: ESRF (European Synchrotron Radiation Facility), 6 rue Jules Horowitz, BP 220, 38043 Grenoble, France.
authors.forename: M G
authors.initials: MG
authors.lastname: Cuypers
authors.forename: E P
authors.initials: EP
authors.lastname: Mitchell
authors.forename: C V
authors.initials: CV
authors.lastname: Romão
authors.forename: S M
authors.initials: SM
authors.lastname: McSweeney
mesh_terms: D000595:Amino Acid Sequence; D001059:Apoproteins / Q000737:chemistry; D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism; D001665:Binding Sites; D002570:Ceruloplasmin / Q000737:chemistry; D018360:Crystallography, X-Ray; D034301:Deinococcus / Q000737:chemistry*; D019281:Dimerization; D007501:Iron / Q000378:metabolism*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D018272:Porins / Q000737:chemistry*; D017510:Protein Folding; D017433:Protein Structure, Secondary; D016415:Sequence Alignment; D055672:Static Electricity
chemical_list: D001059:Apoproteins; D001426:Bacterial Proteins; D018272:Porins; D007501:Iron; D002570:Ceruloplasmin