Solution NMR Structure of a Designed Metalloprotein and Complementary Molecular Dynamics Refinement

Calhoun, Jennifer R.; Liu, Weixia; Spiegel, Katrin; Peraro, Matteo Dal; Klein, Michael L.; Valentine, Kathleen G.; Wand, A. Joshua; DeGrado, William F.

doi:10.1016/j.str.2007.11.011

Cited by 37 publications

(47 citation statements)

References 29 publications

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“…A single chain DF protein, DFsc (with Ala residues around the active site), was also designed, and the NMR structure of di-Zn(II)-DFsc was obtained. 985,986 While rapid oxidation of the diferrous center was observed, it was due to an off-pathway iron-tyrosinate complex and not the important diferric intermediate observed for the other diferrous DF proteins. 987,988 Substitution of the four Ala residues to Gly (G4-DFsc) led to the minimization of this complex and a scaffold, which could also catalyze 4-aminophenol oxidation on the same order of magnitude as DFsc was obtained.…”

Section: De Novo Designmentioning

confidence: 94%

Protein Design: Toward Functional Metalloenzymes

et al. 2014

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Section: De Novo Designmentioning

confidence: 94%

Protein Design: Toward Functional Metalloenzymes

et al. 2014

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“…1–8 Ligand-metal covalence, as most trivially evidenced in redox non-innocent ligands, is one of the defining traits governing homogeneous catalysis. 9–13 The coordination of non-innocent ligands to redox inactive metals can result in intramolecular charge transfer and oxidation of the ligand, thus opening new reaction pathways and enabling unexpected ligand-based reactivity.…”

Section: Introductionmentioning

confidence: 99%

Spin-Polarization-Induced Preedge Transitions in the Sulfur K-Edge XAS Spectra of Open-Shell Transition-Metal Sulfates: Spectroscopic Validation of σ-Bond Electron Transfer

et al. 2017

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Sulfur K-edge XAS spectra of the monodentate sulfate complexes [MII(itao)(SO4)(H2O)0,1] and [Cu(Me6tren)(SO4)] exhibit well-defined pre-edge transitions at 2479.4 eV, 2479.9 eV, 2478.4 eV, and 2477.7 eV, respectively (M = Co, Ni, Cu), despite having no direct metal-sulfur bond, while the XAS pre-edge of [Zn(itao)(SO4)] is featureless. The sulfur K-edge XAS of [Cu(itao)(SO4)] but not of [Cu(Me6tren)(SO4)] uniquely exhibits a weak transition at 2472.1 eV, an extraordinary 8.7 eV below the first inflection of the rising K-edge. Pre-edge transitions also appear in the sulfur K-edge XAS of crystalline [MII(SO4)(H2O)] (M = Fe, Co, Ni, Cu, but not Zn) and in sulfates of higher-valent early transition metals. Ground state density functional theory (DFT) and time-dependent DFT (TDDFT) calculations show that charge transfer from coordinated sulfate to paramagnetic late transition metals produces spin polarization that differentially mixes the spin-up (α) and spin-down (β) spin-orbitals of the sulfate ligand, inducing negative spin density at sulfate sulfur. Ground state DFT calculations show that sulfur 3p character then mixes into metal 4s and 4p valence orbitals and various combinations of ligand anti-bonding orbitals, producing measureable sulfur XAS transitions. TDDFT calculations confirm the presence of XAS pre-edge features 0.5 to 2 eV below the sulfur rising K-edge energy. The 2472.1 eV feature arises when orbitals at lower energy than the frontier occupied orbitals with S 3p character mix with the Cu(II) electron hole. Transmission of spin polarization and thus of radical character through several bonds between the S and the electron hole provides a new mechanism for the counter-intuitive appearance of pre-edge transitions in the XAS spectra of transition metal oxoanion ligands in the absence of any direct metal-absorber bond. The 2472.1 eV transition is evidence for further radicalization from Cu(II), which extends across an H-bond bridge between sulfate and the itao ligand and involves orbitals at energies below the frontier set. This electronic structure feature provides direct spectroscopic confirmation of the through-bond electron transfer mechanism of redox-active metalloproteins.

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“…Early demonstrations showed iron sulfur clusters spontaneously assemble in maquettes 2 singly or in pairs, with or without heme(s); later singlechain variants were designed [Gibney et al, 1996;Mulholland et al, 1998;Musgrave et al, 2002;Nanda et al, 2005;Grzyb et al, 2010;Nanda et al, 2016]. Maquette frames of the kind in Figure 7 have also proved to offer a creative environment for metals alone and in clusters ( Figure 5C) [Dieckmann et al, 1997;Farrer et al, 2000;Calhoun et al, 2005;Geremia et al, 2005;Touw et al, 2007;Calhoun et al, 2008;Tegoni et al, 2012;Zastrow et al, 2012;Roy et al, 2014].…”

Section: First-principles Of De Novo Designed Protein Structures Outlmentioning

confidence: 99%

Maquette Strategy for Creation of Light- and Redox-Active Proteins

Ennist¹,

Mancini²,

Auman³

et al. 2017

Photosynthesis and Bioenergetics

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Twenty five years ago we began utilizing the maquette strategy long used by sculptors and architects to develop first-principles de novo proteins that could perform functions inspired by natural proteins. This brief account traces our approach to engineering light-and redox-driven activities in structurally elementary maquette proteins that reflect little or no primary sequence relationship with those of the inspiring natural system. We follow first-principle maquette protein development from their original production by chemical synthesis of individual helix peptides with di-cystenyl-linked assembly into four-helix bundle proteins, to their bacterial expression as single chain maquette proteins and recently to cellular assembly with selected light-and redox-active cofactors. This last advance includes integration of expressed maquettes with the natural machinery of cofactor maturation and transmembrane transport and extends to maquette fusion with natural cofactor-equipped proteins in cells. Growing experience has led to the recognition that mechanistic components developed en route to one selected maquette function can be retained and applied to the engineering of maquettes designed for other activities. This flexibility plus extraordinary compatibility of maquette proteins with cellular operations explains the large number of maquettes currently in development directed toward performance of a broad range of light and redox driven functions in vitro and in vivo.

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Solution NMR Structure of a Designed Metalloprotein and Complementary Molecular Dynamics Refinement

Cited by 37 publications

References 29 publications

Protein Design: Toward Functional Metalloenzymes

Protein Design: Toward Functional Metalloenzymes

Spin-Polarization-Induced Preedge Transitions in the Sulfur K-Edge XAS Spectra of Open-Shell Transition-Metal Sulfates: Spectroscopic Validation of σ-Bond Electron Transfer

Maquette Strategy for Creation of Light- and Redox-Active Proteins

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