Spectroscopic Studies of Cobalt(II) Binding to Escherichia coli Bacterioferritin

Keech, A.; Brun, Nick E. Le; Wilson, Michael T.; Andrews, Simon C.; Moore, Geoffrey R.; Thomson, Andrew J.

doi:10.1074/jbc.272.1.422

Cited by 31 publications

(31 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…4, Table 2). Furthermore, the spectrum is remarkably similar to the spectra of previous di-Co(II)–DF proteins [8, 12, 17, 21], and to the spectrum of di-Co(II)– bacterioferritin, which contains an identical four Glu, two His binding site (Table 2) [37, 38]. However, di-Co(II)–DF3 exhibits lower molar extinction coefficients per Co(II) ion compared with the other di-Co(II) proteins discussed here.…”

Section: Resultssupporting

confidence: 76%

Spectroscopic and metal-binding properties of DF3: an artificial protein able to accommodate different metal ions

et al. 2010

View full text Add to dashboard Cite

The design, synthesis, and metal-binding properties of DF3, a new de novo designed di-iron protein model are described ("DF" represents due ferri, Italian for "two iron," "di-iron"). DF3 is the latest member of the DF family of synthetic proteins. They consist of helix-loop-helix hairpins, designed to dimerize and form an antiparallel four-helix bundle that encompasses a metal-binding site similar to those of non-heme carboxylate-bridged di-iron proteins. Unlike previous DF proteins, DF3 is highly soluble in water (up to 3 mM) and forms stable complexes with several metal ions (Zn, Co, and Mn), with the desired secondary structure and the expected stoichiometry of two ions per protein. UV-vis studies of Co(II) and Fe(III) complexes confirm a metal-binding environment similar to previous di-Co(II)-and di-Fe(III)-DF proteins, including the presence of a µ-oxo-di-Fe(III) unit. Interestingly, UV-vis, EPR, and resonance Raman studies © SBIC 2010 Correspondence to: Angela Lombardi. suggest the interaction of a tyro-sine adjacent to the di-Fe(III) center. The design of DF3 was aimed at increasing the accessibility of small molecules to the active site of the four-helix bundle. Indeed, binding of azide to the di-Fe(III) site demonstrates a more accessible metal site compared with previous DFs. In fact, fitting of the binding curve to the Hill equation allows us to quantify a 150% accessibility enhancement, with respect to DF2. All these results represent a significant step towards the development of a functional synthetic DF metalloprotein.

show abstract

Section: Resultssupporting

confidence: 76%

Spectroscopic and metal-binding properties of DF3: an artificial protein able to accommodate different metal ions

et al. 2010

View full text Add to dashboard Cite

show abstract

“…7A). This is consistent with the inhibitory effect these elements have on ferroxidase activity35363738; Cu however is usually reported to enhance the ferroxidase activity39. As for Ca and Mg, they showed a potentiation of the light production, especially for Ca although not statistically significant (135.7 ± 30.5%; P = 0.2609).…”

Section: Resultssupporting

confidence: 75%

Evidence that ferritin is associated with light production in the mucus of the marine worm Chaetopterus

Rawat

Deheyn

2016

Sci Rep

View full text Add to dashboard Cite

The blue glow of the mucus from Chaetopterus involves a photoprotein, iron and flavins. Identity and respective role of these components remain, however, largely unresolved today, likely because of viscosity issues and inhibition of this system by oxidizers conventionally used to track bioluminescence activity. Here, we used gentle centrifugation to obtain a mucus supernatant showing no inhibition to oxidizers, allowing for further analysis. We applied conventional chromatographic techniques to isolate major proteins associated with light emission. Luminescence ability of elutriate fractions was tested with hydrogen peroxide to track photoprotein and/or protein-bound chromophore. Fractions producing light contained few major proteins, one with similarity to ferritin. Addition to the mucus of elements with inhibitory/potentiary effect on ferritin ferroxidase activity induced corresponding changes in light production, emphasizing the possible role of ferritin in the worm bioluminescence. DNA of the protein was cloned, sequenced, and expressed, confirming its identity to a Chaetopterus Ferritin (ChF). Both ferric and ferrous iron were found in the mucus, indicating the occurrence of both oxidase and reductase activity. Biochemical analysis showed ChF has strong ferroxidase activity, which could be a source of biological iron and catalytic energy for the worm bioluminescence when coupled to a reduction process with flavins.

show abstract

“…The complex was then diluted with H 2 O͞10% DMSO, lyophilized, and redissolved in 50 mM Mops buffer, pH 7.0 (1.42 10 Ϫ5 M concentration). The UV-visible spectrum was obtained by using a Perkin-Elmer Lambda 7 UV spectrophotometer ( ϭ 524 nm, ϭ 143 M Ϫ1 cm Ϫ1 ; ϭ 574 nm, ϭ 190 M Ϫ1 cm Ϫ1 ; ϭ 594 nm, ϭ 165 M Ϫ1 cm Ϫ1 ; ϭ 625 nm, ϭ 80 M Ϫ1 cm Ϫ1 ; extinction coefficients, calculated per DF1 monomer), are typical of five-coordinate Co(II), and show a very close correspondence with the extinction coefficients of bacterioferritin ( ϭ 520 nm, ϭ 126 M Ϫ1 cm Ϫ1 ; ϭ 555 nm, ϭ 155 M Ϫ1 cm Ϫ1 ; ϭ 600 nm, ϭ 107 M Ϫ1 cm Ϫ1 ; ϭ 625 nm, ϭ 75 M Ϫ1 cm Ϫ1 ) (58).…”

Section: Metal Complex Preparationmentioning

confidence: 98%

Retrostructural analysis of metalloproteins: Application to the design of a minimal model for diiron proteins

Lombardi

Summa

Geremia

et al. 2000

Proc. Natl. Acad. Sci. U.S.A.

233

279

View full text Add to dashboard Cite

De novo protein design provides an attractive approach for the construction of models to probe the features required for function of complex metalloproteins. The metal-binding sites of many metalloproteins lie between multiple elements of secondary structure, inviting a retrostructural approach to constructing minimal models of their active sites. The backbone geometries comprising the metal-binding sites of zinc fingers, diiron proteins, and rubredoxins may be described to within approximately 1 Å rms deviation by using a simple geometric model with only six adjustable parameters. These geometric models provide excellent starting points for the design of metalloproteins, as illustrated in the construction of Due Ferro 1 (DF1), a minimal model for the GluXxx-Xxx-His class of dinuclear metalloproteins. This protein was synthesized and structurally characterized as the di-Zn(II) complex by x-ray crystallography, by using data that extend to 2.5 Å. This four-helix bundle protein is comprised of two noncovalently associated helix-loop-helix motifs. The dinuclear center is formed by two bridging Glu and two chelating Glu side chains, as well as two monodentate His ligands. The primary ligands are mostly buried in the protein interior, and their geometries are stabilized by a network of hydrogen bonds to second-shell ligands. In particular, a Tyr residue forms a hydrogen bond to a chelating Glu ligand, similar to a motif found in the diiron-containing R2 subunit of Escherichia coli ribonucleotide reductase and the ferritins. DF1 also binds cobalt and iron ions and should provide an attractive model for a variety of diiron proteins that use oxygen for processes including iron storage, radical formation, and hydrocarbon oxidation. P roteins use a limited repertoire of metal ion cofactors to help catalyze a multitude of reactions. For example, diiron sites (1-4) mediate reversible oxygen binding in hemerythrins, whereas they function as hydrolytic centers in phosphatases. Structurally similar diiron sites also mediate a number of oxygendependent oxidative processes. Ferritins serve as ferroxidases, while other diiron proteins catalyze hydroxylation, epoxidation, and desaturation reactions. Further, a diiron site in Escherichia coli ribonucleotide reductase is responsible for the formation of a Tyr radical. How do the structures of these proteins tune the chemical properties of a common diiron center to obtain such a diversity of highly specific catalysts? This question is being addressed through the study of the natural proteins as well as the study of small-molecule diiron complexes (1-4). Although impressive progress has been made on both fronts, these approaches have inherent limitations. The study of large proteins is hampered by their extreme complexity, and it is difficult to synthesize small-molecule models capable of simultaneously binding diiron, oxygen, and various substrates. Recently, we and others have sought a molecular middle ground between these two extremes through the design of small proteins and peptid...

show abstract

Spectroscopic Studies of Cobalt(II) Binding to Escherichia coli Bacterioferritin

Cited by 31 publications

References 17 publications

Spectroscopic and metal-binding properties of DF3: an artificial protein able to accommodate different metal ions

Spectroscopic and metal-binding properties of DF3: an artificial protein able to accommodate different metal ions

Evidence that ferritin is associated with light production in the mucus of the marine worm Chaetopterus

Retrostructural analysis of metalloproteins: Application to the design of a minimal model for diiron proteins

Contact Info

Product

Resources

About