Far-Red Resonance Raman Study of Copper A in Subunit II of Cytochrome <i>c</i> Oxidase

Many of the active sites involved in electron transfer (ET) in biology have more than one metal and are mixed valent in at least one redox state. These include Cu(A), and the polynuclear Fe-S clusters which vary in their extent of delocalization. In this tutorial review the relative contributions to delocalization are evaluated using S K-edge X-ray absorption, magnetic circular dichroism and other spectroscopic methods. The role of intra-site delocalization in ET is considered.

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“…This has been probed directly by absorption (Abs) and resonance Raman (rR) spectroscopies. 16,17 Fig. 4C shows the Abs spectrum of Cu A .…”

Section: The Cu a Sitementioning

confidence: 99%

Mixed valent sites in biological electron transfer

2008

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“…Many experimental and theoretical studies have revealed geometrical and electronic properties of the Cu A site1–33. X‐ray crystal structures of the Cu A site from C c O, N 2 OR, and engineered blue copper proteins show the characteristic structural feature, as shown in Figure 16–14, 17–19.…”

Section: Introductionmentioning

confidence: 99%

“…An extended X‐ray absorption fine structure and parallel magnetic circular dichroism data on the oxidized Cu A site propose a directly bonded CuCu unit24, 25, 27–29. Absorption and resonance Raman spectra suggest a transition between the CuCu bonding‐to‐antibonding molecular orbitals of the mixed‐valence oxidized Cu A site associated with the valence delocalization of the Cu 2 S 2 core and provide a strong electronic coupling between the two copper ions24, 28–31. To examine the effect of the CuCu bonding contribution to the CuCu interaction in the Cu 2 S 2 core, the Cu A site was compared to synthetic model complex reported by Tolman and coworkers24, 26, 28, 32.…”

Section: Introductionmentioning

confidence: 99%

Electronic structures of the Cu₂S₂ core of the Cu_A site in cytochrome c oxidase and nitrous oxide reductase

Takano

Shigeta

Koizumi

et al. 2011

Int J of Quantum Chemistry

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ABSTRACT:The Cu A site functions as an electron transfer intermediate in cytochrome c oxidase (CcO) and nitrous oxide reductase. X-ray crystal structures have shown that the Cu A site is a binuclear copper site, bridged by two cysteinyl thiolate groups. Each copper ion is coordinated by a histidine side chain and a weaker axial ligand: a methionine side chain or a backbone carbonyl group. The ground state of the oxidized Cu A site is strongly related to the singly occupied orbital, as the oxidized state of the Cu A site is doublet. Spectroscopic studies have suggested the r u * ground state of the Cu A site due to the direct CuACu interaction, facilitating a rapid electron transfer over long distances with low driving forces. In this study, to elucidate what factors are responsible for the stabilization of the r u * ground state of the Cu A site, the electronic structures of the Cu 2 S 2 core of the Cu A have been studied, using the density functional theory (M06). Our computational results show that the ground state of the Cu 2 S 2 core is the p u state even with a shorter CuACu distance, and that an addition of electrostatic and orbital interactions by ligand coordination stabilizes the r u * state rather than the p u state, because electrostatic repulsion and antibonding orbital interaction between the dr* orbital of the CuACu dimer and the lone pairs of the coordinating His residues rise

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“…It can perform rapid long‐range electron transfer from an electron source such as cytochrome c 2–5. Many experimental and theoretical studies have revealed geometrical and electronic properties of the Cu A site 1–37. Three‐dimensional X‐ray crystallographic structures of the Cu A site from C c O, N 2 OR, and engineered blue copper proteins show the characteristic structural feature, as shown in Figure 1 6–14, 17–19.…”

Section: Introductionmentioning

confidence: 99%

Central pathology review in multicenter trials and studies

Vujanić¹,

Sandstedt²,

Kelsey³

et al. 2009

Cancer

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BACKGROUND:Central pathology review (CPR) is an important component of multicenter tumor trials. The authors retrospectively analyzed the quality of pathology material submitted to determine the benefits and limitations of rapid CPR.METHODS:Analysis of pathology specimens from previous renal tumors in children trials (1980‐2007) included the number of cases submitted, the number of slides per case, discrepancies in diagnosis and staging between institutional pathologists and CPR, and the impact of rapid CPR on treatment.RESULTS:The percentage of cases submitted for CPR increased from 76% in earlier trials to 100% in the current trial. The number of slides submitted rose from a median of 6 (International Pediatric Oncology Society [SIOP] 9301) to 25 for the SIOP‐UK Renal Tumors 2001 trial. Discrepancies between the institutional pathologists and CPR were as follows: diagnosis: SIOP 9, 17%; SIOP 93‐01, 14%; United Kingdom Wilms Tumour 3 Trial (UKWT3), 3.5%; SIOP‐UK 2001, 3.8%; staging: SIOP 6, 9%; SIOP 93‐01, 14%; UKWT3, 17%; SIOP‐UK 2001, 3.8% of cases. There were clinically significant discrepancies in diagnosis and/or stage in 30 of 152 (20%) cases submitted for delayed CPR in SIOP‐UK 2001.CONCLUSIONS:The number and quality of material submitted for CPR has markedly improved over time, predominantly due to the introduction of a simple standard operating procedure. Discrepancies in diagnosis and staging remain, but rapid review CPR allows clinicians to modify treatment if required. Benefits from the CPR system followed in SIOP‐UK 2001 have been clearly demonstrated, and similar systems should be considered for future trials of other tumors. Cancer 2009. © 2009 American Cancer Society.

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Far-Red Resonance Raman Study of Copper A in Subunit II of Cytochrome c Oxidase

Cited by 44 publications

References 33 publications

Mixed valent sites in biological electron transfer

Mixed valent sites in biological electron transfer

Electronic structures of the Cu₂S₂ core of the Cu_A site in cytochrome c oxidase and nitrous oxide reductase

Central pathology review in multicenter trials and studies

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Far-Red Resonance Raman Study of Copper A in Subunit II of Cytochrome c Oxidase

Cited by 44 publications

References 33 publications

Mixed valent sites in biological electron transfer

Mixed valent sites in biological electron transfer

Electronic structures of the Cu2S2 core of the CuA site in cytochrome c oxidase and nitrous oxide reductase

Central pathology review in multicenter trials and studies

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Electronic structures of the Cu₂S₂ core of the Cu_A site in cytochrome c oxidase and nitrous oxide reductase