Electronic structures of active sites in copper proteins: contributions to reactivity

Solomon, Edward I.; Baldwin, Michael J.; Lowery, Michael D.

doi:10.1021/cr00012a003

Cited by 881 publications

(553 citation statements)

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“…The other striking feature was the strong blue colour of the proteins in the oxidized state which corresponds to a strong absorption around 600 nm with an extinction (3000-6000 M-'cm-'). This is about an order of magnitude (or more larger) than that of an ordinary Cu coordination compound in this spectral region [8].…”

Section: Type 1 Copper Sitesmentioning

confidence: 70%

“…The spectroscopic features of type 1 Cu sites have intrigued coordination chemists for a long time as they could not be understood on the basis of the then current knowledge of the coordination chemistry of copper. The EPR spectrum has an axial appearance with g, C g, < g; it sometimes exhibits a small rhombic distortion [8]. The relative order of the g-values indicates that the unpaired electron in the Cu(I1) ground state resides in the dx2+ orbital.…”

Section: Type 1 Copper Sitesmentioning

confidence: 99%

“…The relative order of the g-values indicates that the unpaired electron in the Cu(I1) ground state resides in the dx2+ orbital. One of the puzzling observations was the very small value of the Cu hyperfine splitting, A,,, in the g,, region of the EPR spectrum, which amounted to I 70 x 10e4 cm-' and for which there was no precedent [8]. The other striking feature was the strong blue colour of the proteins in the oxidized state which corresponds to a strong absorption around 600 nm with an extinction (3000-6000 M-'cm-').…”

Section: Type 1 Copper Sitesmentioning

confidence: 99%

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Engineering type 1 copper sites in proteins

1993

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The use of site-directed mutagenesis methods has revolutionalized the study of the so-called type 1 and type 2 copper sites in proteins. In particular our understanding of the relation between the structure, and the mechanistic and spectroscopic features of these sites is benefitting from the application of these techniques. Recent progress in the field is reviewed with emphasis on the study of type 1 sites. Topics covered comprise the characteristics of the natural type 1 and type 2 sites, the genetics of blue copper proteins, the modification of Cu sites, the spectroscopy of natural and engineered type 1 and type 2 sites, the effect of mutations on midpoint potentials and the mechanism of electron transfer as carried out by the blue copper proteins.

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Section: Type 1 Copper Sitesmentioning

confidence: 70%

Section: Type 1 Copper Sitesmentioning

confidence: 99%

Section: Type 1 Copper Sitesmentioning

confidence: 99%

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Engineering type 1 copper sites in proteins

1993

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“…At low temperature these axially distorted states are frozen in, and it is possible to observe their EPR spectrum. The reduction in the hyperfine splitting parameter in the direction of the symmetry axis (A | ) characteristic of the EPR spectra of type 1 blue copper protein, is due to the highly covalent S Cys equatorial bond 56,57 and does not occur in Cu: Zn(D,L-histidine) 2 . ENDOR and ESEEM data on Cu ions in Zn-(D,L-histidine) 2 would allow to obtain more information about the bonding scheme, to verify the proposed model.…”

Section: Discussionmentioning

confidence: 99%

Structure, Disorder, and Molecular Dynamics in Zn(d,l-histidine)₂: EPR of Copper Ion Dopants, X-ray Diffraction, and Calorimetric Studies

Dalosto¹,

Calvo²,

Pizarro³

et al. 2001

J. Phys. Chem. A

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We report EPR, X-ray crystallographic, and calorimetric measurements in copper-doped and pure Zn(II) bis(D,L-histidino)pentahydrate (C 12 H 26 N 6 O 9 Zn), to be called Zn(D,L-histidine) 2 . EPR data in copper-doped single crystals were obtained at 9.8 GHz as a function of the orientation of the magnetic field B at 298 and 80 K, and as a function of temperature (T) for fixed orientations of B. Powder samples were studied at 9.8 and 35 GHz. Steep changes of the EPR spectra with temperature occur around T c ) 268 K. Above T c we observe spectra arising from a single copper with rhombic g and copper hyperfine A tensors. The resonances display a strong dependence of the line width with the hyperfine component. Below T c the spectra can be assigned to two different copper ions displaying axial symmetry and related by a C 2 rotation. As T increases approaching T c , they collapse into the high-temperature spectrum. A peak in the differential specific heat of pure Zn(D,L-histidine) 2 between 235 and 270 K indicates a transition intrinsic to the host material. Full X-ray structural studies were performed at 293 and at 150 K, above and below T c . At 293 K our results are similar to those reported before. The low-temperature data show disorder in the water molecules. We interpret the experimental results with a model where the copper atoms hop randomly between different states. This dynamics is related to the fluctuating disorder in the lattice and produces steep changes on the EPR spectra of copper ion dopants. The role of dynamic Jahn-Teller distortions is discussed. A bonding scheme for the copper ions in Zn(D,L-histidine) 2 is proposed, and it is compared with that encountered in type 1 blue copper proteins.

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“…Nevertheless, currently applied incubation times of 30 and more minutes are too long to be economical. An important hindrance in reaction efficiency is its low redox-potential of the enzymes (Solomon et al 1992, Shleev et al 2004. Screening for mutations by modern molecular biological techniques can yield enzymes with higher redox-potential for recombinant production , Zumarraga et al 2007; further reading in Chapter 19 of this book).…”

Section: Homogenisationmentioning

confidence: 99%

Wood production, wood technology, and biotechnological impacts

Kües¹

2007

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Electronic structures of active sites in copper proteins: contributions to reactivity

Cited by 881 publications

References 23 publications

Engineering type 1 copper sites in proteins

Engineering type 1 copper sites in proteins

Structure, Disorder, and Molecular Dynamics in Zn(d,l-histidine)₂: EPR of Copper Ion Dopants, X-ray Diffraction, and Calorimetric Studies

Wood production, wood technology, and biotechnological impacts

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Electronic structures of active sites in copper proteins: contributions to reactivity

Cited by 881 publications

References 23 publications

Engineering type 1 copper sites in proteins

Engineering type 1 copper sites in proteins

Structure, Disorder, and Molecular Dynamics in Zn(d,l-histidine)2: EPR of Copper Ion Dopants, X-ray Diffraction, and Calorimetric Studies

Wood production, wood technology, and biotechnological impacts

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Product

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Structure, Disorder, and Molecular Dynamics in Zn(d,l-histidine)₂: EPR of Copper Ion Dopants, X-ray Diffraction, and Calorimetric Studies