Metal sites in small blue copper proteins, blue copper oxidases and vanadium-containing enzymes

Messerschmidt, Albrecht

doi:10.1007/3-540-62888-6_2

Cited by 102 publications

(75 citation statements)

References 106 publications

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“…1 to Fig. 4) are typical for type 2 protein-Cu(II) complexes (axial g matrix, copper hyperfine splitting, A ʈ Ͼ400 MHz) (29). Type 2 complexes are largely square planar with a possible fifth weak coordination.…”

Section: Resultsmentioning

confidence: 88%

Copper(II) Binding to the Human Doppel Protein May Mark Its Functional Diversity from the Prion Protein

Cereghetti¹,

Negro²,

Vinck

et al. 2004

Journal of Biological Chemistry

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Section: Resultsmentioning

confidence: 88%

Copper(II) Binding to the Human Doppel Protein May Mark Its Functional Diversity from the Prion Protein

Cereghetti¹,

Negro²,

Vinck

et al. 2004

Journal of Biological Chemistry

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“…The copper ion forms a type 1 Cu-binding site ( Fig. 1), which is characterized by a bright blue color, a narrow hyperfine splitting in the electron paramagnetic resonance (EPR) spectra, a high reduction potential (13)(14)(15), and a strong structural similarity between oxidized and reduced states (13)(14)(15)(16)(17). In fact, in both oxidation states, the copper ion is coordinated by a cysteine (Cys) thiolate group and two histidine (His) nitrogen atoms in a trigonal planar conformation.…”

mentioning

confidence: 99%

Role of protein frame and solvent for the redox properties of azurin from Pseudomonas aeruginosa

Cascella

Magistrato

Tavernelli

et al. 2006

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

140

164

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We have coupled hybrid quantum mechanics (density functional theory; Car-Parrinello)/molecular mechanics molecular dynamics simulations to a grand-canonical scheme, to calculate the in situ redox potential of the Cu 2؉ ؉ e ؊ 3 Cu ؉ half reaction in azurin from Pseudomonas aeruginosa. An accurate description at atomistic level of the environment surrounding the metal-binding site and finite-temperature fluctuations of the protein structure are both essential for a correct quantitative description of the electronic properties of this system. We report a redox potential shift with respect to copper in water of 0.2 eV (experimental 0.16 eV) and a reorganization free energy ‫؍‬ 0.76 eV (experimental 0.6 -0.8 eV). The electrostatic field of the protein plays a crucial role in fine tuning the redox potential and determining the structure of the solvent. The inner-sphere contribution to the reorganization energy is negligible. The overall small value is mainly due to solvent rearrangement at the protein surface.density functional theory ͉ electron transfer ͉ molecular dynamics ͉ reorganization energy E lectron transfer (ET) processes are ubiquitous chemical reactions that occur in a variety of essential biological functions, such as immune response, respiration, and photosynthesis (1-10). Among the different families of ET proteins, single-copper cupredoxins, also known as blue copper proteins, are particularly appealing for theoretical studies because of their relatively small size and the great availability of experimental measurements in the literature. Blue copper proteins exchange electrons among themselves or with other redox proteins, such as cytochrome c551 or nitrite reductase, using a protein-bound Cu metal ion, that can exist in the Cu(II) or Cu(I) redox states (11,12). The copper ion forms a type 1 Cu-binding site ( Fig. 1), which is characterized by a bright blue color, a narrow hyperfine splitting in the electron paramagnetic resonance (EPR) spectra, a high reduction potential (13-15), and a strong structural similarity between oxidized and reduced states (13-17). In fact, in both oxidation states, the copper ion is coordinated by a cysteine (Cys) thiolate group and two histidine (His) nitrogen atoms in a trigonal planar conformation. The coordination polyhedron is completed by one axial ligand, typically a methionine (Met) thioether group. In azurin, a backbone amide oxygen of a glycine (Gly) constitutes an additional axial ligand (18). The structural similarity between the two redox states provides an advantage for the functionality of these ET proteins, as the reorganization free energy () for the redox process is small [0.6-0.8 eV (17, 19)], allowing a high ET rate (20-23). This is not the case for solvated copper ions and synthetic Cu complexes, which tend to have large structural changes concurrent with any variation in their oxidation state (24). The origin of the low value of is still unclear. The initial hypothesis implied that the rigidity of the protein would force Cu(II) to be bound in a geomet...

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“…The difference in color arises from subtle differences in the geometry and ligand donor set about the copper active site (12). For example, blue copper proteins, such as plastocyanin, azurin, laccase, NIR, and ceruloplasmin, have a mononuclear copper active site, the copper-thiolate bond of which resides in a trigonal geometry about the copper ion in addition to two copper-histidine coordinations (1,8,9,11,26) (Fig. 1A).…”

mentioning

confidence: 99%

Experimental evidence for a link among cupredoxins: Red, blue, and purple copper transformations in nitrous oxide reductase

Savelieff¹,

Wilson²,

Youssef³

et al. 2008

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

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The cupredoxin fold is an important motif in numerous proteins that are central to several critical cellular processes ranging from aerobic and anaerobic respiration to catalysis and iron homeostasis. Three types of copper sites have been found to date within cupredoxin folds: blue type 1 (T1) copper, red type 2 (T2) copper, and purple Cu A. Although as much as 90% sequence difference has been observed among some members of this superfamily of proteins that span several kingdoms, sequence alignment and phylogenic trees strongly suggest an evolutionary link and common ancestry. However, experimental evidence for such a link has been lacking. We report herein the observation of pH-dependent transformation between blue T1 copper, red T2 copper, and the native purple Cu A centers of nitrous oxide reductase (N2OR) from Paracoccus denitrificans. The blue and red copper centers form initially before they are transformed into purple Cu A center. This transformation process is pH-dependent, with lower pH resulting in fewer trapped T1 and T2 coppers and faster transition to purple Cu A. These observations suggest that the purple CuA site contains the essential elements of T1 and T2 copper centers and that the Cu A center is preferentially formed at low pH. Therefore, this work provides an underlying link between the various cupredoxin copper sites and possible experimental evidence in vitro for the evolutionary relationship between the cupredoxin proteins. The findings also lend physiological relevance to cupredoxin site biosynthesis.blue type 1 copper ͉ purple copper CuA ͉ red type 2 copper ͉ folding ͉ kinetics

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Metal sites in small blue copper proteins, blue copper oxidases and vanadium-containing enzymes

Cited by 102 publications

References 106 publications

Copper(II) Binding to the Human Doppel Protein May Mark Its Functional Diversity from the Prion Protein

Copper(II) Binding to the Human Doppel Protein May Mark Its Functional Diversity from the Prion Protein

Role of protein frame and solvent for the redox properties of azurin from Pseudomonas aeruginosa

Experimental evidence for a link among cupredoxins: Red, blue, and purple copper transformations in nitrous oxide reductase

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