Reduction potential variations in azurin through secondary coordination sphere phenylalanine incorporations

Berry, Steven M.; Baker, Madelyn H.; Reardon, Nicole J.

doi:10.1016/j.jinorgbio.2010.06.004

Cited by 42 publications

(51 citation statements)

References 91 publications

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“…Abbreviations used: AcoP _A.f : Acidophile cytochrome c oxidase Partner from Acidithiobacillus ferrooxidans (current study); Ami _M.e : amicyanin from Methylobacterium extorquens [59]; Aur C _C.a and Aur D _C.a : auracyanin C and D from Chloroflexus aurantiacus [48]; Azu-1_ M.sp and Azu-2_ M.sp: azurin isoform 1 and 2 from Methylomonas sp. [59]; Azu_ P.a: azurin from Pseudomonas aeruginosa [55], [60]; CBP_ Cu: cucumber basic protein from Cucumber [19]; Lpc_ S.c: lipocyanin from Streptomyces coelicolor [61]; Nir_ A.c: Nitrite reductase from Achromobacter cycloclastes [19]; Nitroso_ N.e: nitrosocyanin from Nitrosomonas europaea [62]; Paz_ Ac : pseudoazurin from Achromobacter cycloclastes [60]; Plc_ Sp : plastocyanin from spinach [60]; Rus _ A.f: rusticyanin from Acidithiobacillus ferrooxidans (current study) [34]; Ste _Cu: stellacyanin from Cucumber [63], [64].…”

Section: Resultsmentioning

confidence: 99%

“…Site directed mutagenesis has shown that redox potential can be modulated by amino acid substitution in the vicinity of copper [51], [52], [53]. As observed for rusticyanin, hydrophobic patches close to the metal binding site appear to increase redox potentials, since they exclude water or residues with electronegative ligand atoms [54], [55].…”

Section: Discussionmentioning

confidence: 99%

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Spectroscopic Characterization of a Green Copper Site in a Single-Domain Cupredoxin

et al. 2014

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Cupredoxins are widespread copper-binding proteins, mainly involved in electron transfer pathways. They display a typical rigid greek key motif consisting of an eight stranded β-sandwich. A fascinating feature of cupredoxins is the natural diversity of their copper center geometry. These geometry variations give rise to drastic changes in their color, such as blue, green, red or purple. Based on several spectroscopic and structural analyses, a connection between the geometry of their copper-binding site and their color has been proposed. However, little is known about the relationship between such diversity of copper center geometry in cupredoxins and possible implications for function. This has been difficult to assess, as only a few naturally occurring green and red copper sites have been described so far. We report herein the spectrocopic characterization of a novel kind of single domain cupredoxin of green color, involved in a respiratory pathway of the acidophilic organism Acidithiobacillus ferrooxidans. Biochemical and spectroscopic characterization coupled to bioinformatics analysis reveal the existence of some unusual features for this novel member of the green cupredoxin sub-family. This protein has the highest redox potential reported to date for a green-type cupredoxin. It has a constrained green copper site insensitive to pH or temperature variations. It is a green-type cupredoxin found for the first time in a respiratory pathway. These unique properties might be explained by a region of unknown function never found in other cupredoxins, and by an unusual length of the loop between the second and the fourth copper ligands. These discoveries will impact our knowledge on non-engineered green copper sites, whose involvement in respiratory chains seems more widespread than initially thought.

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Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Spectroscopic Characterization of a Green Copper Site in a Single-Domain Cupredoxin

et al. 2014

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“…E m was found to vary linearly with log P , a measure of the hydrophobicity of the amino acid at position 121. This work was extended by Berry and coworkers, who introduced phenylalanine residues surrounding the metal-binding site [34]. The added hydrophobicity of these residues elevated E m by approximately 30 mV per phenylalanine with minimal perturbations to the Cu II electronic structure.…”

Section: Cumentioning

confidence: 95%

Biological Outer-Sphere Coordination

Lancaster

2011

Molecular Electronic Structures of Transition Metal Complexes I

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The concept of outer-sphere coordination (OSC) is surveyed in the context of bioinorganic chemistry. A distinction is made between electronic and structural OSC, both arising from the interaction of the protein matrix with inner sphere ligands. Electronic OSC entails the electronic interaction between the polypeptide and inner-sphere ligands. These effects principally arise from hydrogenbonding interactions, though through-space dipolar interactions are also encountered. Structural OSC comprises primarily steric effects that do not necessarily impact ligand electronics but rather influence inner sphere topology. Additionally, the protein matrix can be envisioned as a local "solvent" whose bulk dielectric and point charges influence the metal center. Recurring themes are highlighted where OSC regulates the properties of various metalloproteins distinguished by cofactors and/or function. Finally, cases are presented where OSC has guided molecular design.

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“…Other factors that contribute to E° differences among T1 Cu centers include the hydrophobicity of nearby residues, hydrogen bonding to the S(Cys), and electrostatic interactions in the protein backbone [51, 52]. The effects on E° due to hydrogen bonds and protein dipole interactions have been investigated [53, 54].…”

Section: Electron Transfer Properties Of the T1 Coppermentioning

confidence: 99%

Electron transfer and reaction mechanism of laccases

Jones

Solomon

2015

Cell. Mol. Life Sci.

466

358

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Laccases are part of the family of multicopper oxidases (MCOs), which couple the oxidation of substrates to the four electron reduction of O2 to H2O. MCOs contain a minimum of four Cu's divided into Type 1 (T1), Type 2 (T2), and binuclear Type 3 (T3) Cu sites that are distinguished based on unique spectroscopic features. Substrate oxidation occurs near the T1, and electrons are transferred approximately 13 Å through the protein via the Cys-His pathway to the T2/T3 trinuclear copper cluster (TNC) where dioxygen reduction occurs. This review outlines the electron transfer (ET) process in laccases, and the mechanism of O2 reduction as elucidated through spectroscopic, kinetic, and computational data. Marcus theory is used to describe the relevant factors which impact ET rates including the driving force (ΔG°), reorganization energy (λ), and electronic coupling matrix element (HDA). Then the mechanism of O2 reaction is detailed with particular focus on the intermediates formed during the two 2e− reduction steps. The first 2e− step forms the peroxide intermediate (PI), followed by the second 2e− step to form the native intermediate (NI), which has been shown to be the catalytically relevant fully oxidized form of the enzyme.

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Reduction potential variations in azurin through secondary coordination sphere phenylalanine incorporations

Cited by 42 publications

References 91 publications

Spectroscopic Characterization of a Green Copper Site in a Single-Domain Cupredoxin

Spectroscopic Characterization of a Green Copper Site in a Single-Domain Cupredoxin

Biological Outer-Sphere Coordination

Electron transfer and reaction mechanism of laccases

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