Cu(I) Luminescence from the Tetranuclear Cu<sub>4</sub>S<sub>4</sub> Cofactor of a Synthetic 4-Helix Bundle

Kharenko, Olesya A.; Kennedy, David C.; Demeler, Borries; Maroney, Michael J.; Ogawa, Michael Y.

doi:10.1021/ja042757m

Cited by 53 publications

(79 citation statements)

References 17 publications

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“…2,4 To further expand the tools for preparing such materials, continuing efforts are being directed towards gaining a better understanding of how various combination of non-covalent interactions can be used to prepare self-assembled materials having predictable and well-defined morphologies. 6,7 Inspired by workers in the field of supramolecular coordination chemistry, we [8][9][10][11][12] and others [13][14][15][16] have been exploring a new route for preparing self-assembled materials which uses transition metal chemistry to help direct the organization of self-assembling polypeptides in ways that may add to, and perhaps complement, the existing repertoire of native protein structures. This approach of "metal-mediated peptide assembly" coordinates Vol.…”

Section: Introductionmentioning

confidence: 99%

Self-Organization of porphyrin-peptide units by metal-mediated peptide assembly

Carvalho¹,

Ogawa²

2010

J. Braz. Chem. Soc.

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O polipeptídeo H21(30-mer) forma dímeros "coiled-coil" que apresentam dois resíduos histidínicos expostos ao solvente nos lados opostos de sua superfície. Este peptídeo reage com a protoporfirina IX de cobalto, Co(ppIX), para produzir [Co(ppIX){(H21(30-mer)} 2 ], como determinado por espectroscopia UV-Vis. Esta ligação bi-axial disponibiliza um potencial domínio de oligomerização "coiled-coil" em cada face do anel porfirínico de cobalto. Dicroísmo circular e cromatografia líquida de exclusão de alto desempenho forneceram evidências da auto-organização destas unidades porfirina-peptídeo em solução. A evaporação da solução porfirina-peptídeo em uma superfície sólida resultou na formação de longos materiais cilíndricos com milímetros de comprimento e micrometros de diâmetro. A presença do complexo Co(ppIX) nestes materiais foi confirmada por microscopia Raman. Estes materiais, entretanto, foram formados somente com o tampão fosfato, e não com tampões orgânicos ou água pura, indicando que sua formação deve envolver um processo mais complicado do que originalmente antecipado.The polypeptide H21(30-mer) folds into a two-stranded coiled-coil in which two solventexposed histidine residues reside on opposite sides of its surface. This peptide was allowed to react with cobalt(III) protoporphyrin IX, Co(ppIX), to produce [Co(ppIX){(H21(30-mer)} 2 ], as determined by UV-Vis spectroscopy. This bis-axial ligation thus positions a potential coiledcoil oligomerization domain onto each face of the cobalt porphyrin ring. Circular dichroism spectroscopy and high performance size exclusion chromatography provide evidence for the solution-phase self-assembly of these porphyrin-peptide units. Evaporation of the porphyrinpeptide solution on a solid support results in the formation of long rod-like materials having millimeter-scale lengths and micron-scale diameters. The presence of Co(ppIX) in these materials was confirmed by Raman microscopy. However, they were formed only from phosphate buffer, and not from organic buffers or pure water, indicating that their formation might involve a more complicated process than originally anticipated.Keywords: cobalt protoporphyrin IX, peptides, fibers, self-assembly IntroductionMolecular self-assembly has proven to be a valuable approach towards the bottom-up design of synthetic materials. [1][2][3][4][5] Much inspiration for this work comes from biological precedents in which optimal combinations of hydrogen-bond, electrostatic, and hydrophobic interactions are used to assemble polypeptides and nucleic acids into robust structural motifs. 2,4 To further expand the tools for preparing such materials, continuing efforts are being directed towards gaining a better understanding of how various combination of non-covalent interactions can be used to prepare self-assembled materials having predictable and well-defined morphologies. 6,7 Inspired by workers in the field of supramolecular coordination chemistry, we 8-12 and others [13][14][15][16] have been exploring a new route for preparing self-assem...

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Section: Introductionmentioning

confidence: 99%

Self-Organization of porphyrin-peptide units by metal-mediated peptide assembly

Carvalho¹,

Ogawa²

2010

J. Braz. Chem. Soc.

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“…The substantial research incorporating metal cofactors into designed peptide frameworks has been described in several recent reviews (13-15). Helical scaffolds have been the predominant structural motif used for the incorporation of many types of metal-binding sites, including hemes (16), iron-sulfur clusters (17), dinuclear metal centers (18), copper centers (19,20), and heavy metal-binding trigonal thiolate sites (7,21). ␤-Hairpins and other globular structures that bind As(III), Zn(II), and other metal cofactors have also been designed (22)(23)(24)(25).…”

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Identifying important structural characteristics of arsenic resistance proteins by using designed three-stranded coiled coils

Touw

Nordman

Stuckey³

et al. 2007

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

154

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Arsenic, a contaminant of water supplies worldwide, is one of the most toxic inorganic ions. Despite arsenic's health impact, there is relatively little structural detail known about its interactions with proteins. Bacteria such as Escherichia coli have evolved arsenic resistance using the Ars operon that is regulated by ArsR, a repressor protein that dissociates from DNA when As(III) binds. This protein undergoes a critical conformational change upon binding As(III) with three cysteine residues. Unfortunately, structures of ArsR with or without As(III) have not been reported. Alternatively, de novo designed peptides can bind As(III) in an endo configuration within a thiolate-rich environment consistent with that proposed for both ArsR and ArsD. We report the structure of the As(III) complex of Coil Ser L9C to a 1.8-Å resolution, providing x-ray characterization of As(III) in a Tris thiolate protein environment and allowing a structural basis by which to understand arsenated ArsR.arsenic-binding proteins ͉ coiled coil peptides ͉ crystallography ͉ heavy metal toxicity ͉ protein design A rsenic toxicity is a worldwide problem as a natural contaminant of water supplies. Despite the fact that it is a human toxin and carcinogen, few structural reports on its interaction with biological ligands have appeared. Escherichia coli and other bacteria have evolved a detoxification mechanism that employs the arsRDABC operon (1). Arsenic removal by these encoded proteins is initiated when As(III) binds to ArsR, resulting in the dissociation of the repressor protein from the promoter DNA. The structure of the ArsA component of the ATP-dependent extrusion pump ArsAB with antimonite bound in close proximity to the nucleotide-binding site was able to provide some insight into the active transport of As(III) out of the cell (2). Additionally, structural characterization of substrate and product complexes of the arsenate reductase ArsC, which reduces arsenate (AsO 4 3Ϫ ) to arsenite (AsO 2 Ϫ ), has helped elucidate this step of the arsenic detoxification pathway (3, 4). Recent studies of E. coli ArsD indicate that it is a metallochaperone, transporting As(III) to ArsA for extrusion (5). Extended x-ray absorption fine structure and mutagenesis studies have shown that ArsR coordinates As(III) with three cysteine thiolates at a distance of 2.25 Å, a coordination mode that ArsD is also proposed to employ (1, 5). However, no x-ray or NMR structures of ArsR, the repressor protein, or ArsD have been reported to date. Furthermore, AsS 3 structures have not been reported for any biologically relevant small-molecule thiolates, such as glutathione, and only a handful of related AsS 3 complexes with aromatic ligands or chelated alkyl dithiolate coordination are reported (6).We set out to model the putative As(III) coordination environments of ArsR and ArsD in a designed peptide system. Previously, we have shown that the three-stranded coiled coildesigned with the heptad repeat strategy, such as TRI L16C (sequences of all peptides are in Table 1...

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“…Whereas the observation of decreasing ET rates with increasing driving force has long been observed in unimolecular, [7] or otherwise diffusionally restricted donor/acceptor systems, [8,9] such behavior has rarely been seen when the donor and acceptor complexes are allowed to diffuse freely in solution. [10,11] Our group recently reported [5,6] the metal-binding properties of the 32-residue polypeptide C16C19-GGY whose sequence is based on the (IEALEGK) n heptad repeat previously shown to self-assemble into a-helical coiled coils. [12,13] However, the third heptad repeat of C16C19-GGY was modified by substituting cysteine residues at positions 16 and 19 of the sequence to construct a potential metal-binding site within the hydrophobic core of the coiled coil.…”

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Evidence That a Miniature Cu^I Metalloprotein Undergoes Collisional Electron Transfer in the Inverted Marcus Region

et al. 2006

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Cu(I) Luminescence from the Tetranuclear Cu₄S₄ Cofactor of a Synthetic 4-Helix Bundle

Cited by 53 publications

References 17 publications

Self-Organization of porphyrin-peptide units by metal-mediated peptide assembly

Self-Organization of porphyrin-peptide units by metal-mediated peptide assembly

Identifying important structural characteristics of arsenic resistance proteins by using designed three-stranded coiled coils

Evidence That a Miniature Cu^I Metalloprotein Undergoes Collisional Electron Transfer in the Inverted Marcus Region

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Cu(I) Luminescence from the Tetranuclear Cu4S4 Cofactor of a Synthetic 4-Helix Bundle

Cited by 53 publications

References 17 publications

Self-Organization of porphyrin-peptide units by metal-mediated peptide assembly

Self-Organization of porphyrin-peptide units by metal-mediated peptide assembly

Identifying important structural characteristics of arsenic resistance proteins by using designed three-stranded coiled coils

Evidence That a Miniature CuI Metalloprotein Undergoes Collisional Electron Transfer in the Inverted Marcus Region

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Cu(I) Luminescence from the Tetranuclear Cu₄S₄ Cofactor of a Synthetic 4-Helix Bundle

Evidence That a Miniature Cu^I Metalloprotein Undergoes Collisional Electron Transfer in the Inverted Marcus Region