3is7

Structure of mineralized Bfrb from Pseudomonas aeruginosa to 2.1A Resolution

spinqualitylabelsall models 3is7, resolution 2.10Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3is7 is a 24 chain structure with sequence from "bacillus_aeruginosus"_(schroeter_1872)_trevisan_1885 "bacillus aeruginosus" (schroeter 1872) trevisan 1885. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: HEM, K Related: 3is8, 3ise, 3isf Gene: bfrB, PA3531 ("Bacillus aeruginosus" (Schroeter 1872) Trevisan 1885) Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [Q9HY79_PSEAE] Iron-storage protein (By similarity). Iron-storage protein, whose ferroxidase center binds Fe(2+) ions, oxidizes them by dioxygen to Fe(3+), and participates in the subsequent Fe(3+) oxide mineral core formation within the central cavity of the protein complex (By similarity).[PIRNR:PIRNR002560] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMed The structure of recombinant Pseudomonas aeruginosa bacterioferritin B (Pa BfrB) has been determined from crystals grown from protein devoid of core mineral iron (as-isolated) and from protein mineralized with approximately 600 iron atoms (mineralized). Structures were also obtained from crystals grown from mineralized BfrB after they had been soaked in an FeSO(4) solution (Fe soak) and in separate experiments after they had been soaked in an FeSO(4) solution followed by a soak in a crystallization solution (double soak). Although the structures consist of a typical bacterioferritin fold comprised of a nearly spherical 24-mer assembly that binds 12 heme molecules, comparison of microenvironments observed in the distinct structures provided interesting insights. The ferroxidase center in the as-isolated, mineralized, and double-soak structures is empty. The ferroxidase ligands (except His130) are poised to bind iron with minimal conformational changes. The His130 side chain, on the other hand, must rotate toward the ferroxidase center to coordinate iron. In comparison, the structure obtained from crystals soaked in an FeSO(4) solution displays a fully occupied ferroxidase center and iron bound to the internal, Fe((in)), and external, Fe((out)), surfaces of Pa BfrB. The conformation of His130 in this structure is rotated toward the ferroxidase center and coordinates an iron ion. The structures also revealed a pore on the surface of Pa BfrB that likely serves as a port of entry for Fe(2+) to the ferroxidase center. On its opposite end, the pore is capped by the side chain of His130 when it adopts its "gate-closed" conformation that enables coordination to a ferroxidase iron. A change to its "gate-open", noncoordinative conformation creates a path for the translocation of iron from the ferroxidase center to the interior cavity. These structural observations, together with findings obtained from iron incorporation measurements in solution, suggest that the ferroxidase pore is the dominant entry route for the uptake of iron by Pa BfrB. These findings, which are clearly distinct from those made with Escherichia coli Bfr [Crow, A. C., Lawson, T. L., Lewin, A., Moore, G. R., and Le Brun, N. E. (2009) J. Am. Chem. Soc. 131, 6808-6813], indicate that not all bacterioferritins operate in the same manner. Structural Studies of Bacterioferritin B from Pseudomonas aeruginosa Suggest a Gating Mechanism for Iron Uptake via the Ferroxidase Center .,Weeratunga SK, Lovell S, Yao H, Battaile KP, Fischer CJ, Gee CE, Rivera M Biochemistry. 2010 Jan 21. PMID:20067302 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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