Electron nuclear double resonance of cytochrome oxidase: Nitrogen and proton endor from the ‘copper’ EPR signal

Camp, H. L. Van; Wei, Yau‐Huei; Scholes, Charles P.; King, Tsoo E.

doi:10.1016/0005-2795(78)90507-x

Cited by 37 publications

(13 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…1 the X-band EPR spectrum of the g = 2 region of a frozen solution of cytochrome oxidase is shown. The signal from the "intrinsic Cu" site is free from features associated with adventitiously bound copper (7) and, except for possibly higher resolution brought about by the glycerol in the medium, is in complete accord with the spectrum published by van Camp et al (11). Both these spectra (see Fig.…”

Section: Resultssupporting

confidence: 79%

“…(9) have recently reported the resolution in.2-to 4-GHz EPR of hyperfine structure that may be-from copper. However, it has also been noted that the spectra features listed above are characteristic of thiyl radicals (R-S.) (10), and, in a recent electron-nuclear double resonance (ENDOR) investigation of cytochrome oxidase, proton and nitrogen ENDOR was observed, but copper could not be detected (11).…”

mentioning

confidence: 99%

See 1 more Smart Citation

Copper electron-nuclear double resonance of cytochrome c oxidase.

Hoffman¹,

Roberts²,

Swanson³

et al. 1980

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

View full text Add to dashboard Cite

show abstract

Section: Resultssupporting

confidence: 79%

mentioning

confidence: 99%

Copper electron-nuclear double resonance of cytochrome c oxidase.

Hoffman¹,

Roberts²,

Swanson³

et al. 1980

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

View full text Add to dashboard Cite

show abstract

“…For strongly coupled protons of both ubiquinone here and metal systems like CuA of cytochrome c oxidase (Van Camp et al, 1978), we found that the higher frequency partner of the proton pair predicted in eq 1 was more intense than the lower frequency partner. Such an intensity difference may be due to the competing effects on ENDOR transition probability from direct RF-induced nuclear transitions and from RF-induced modulation of the hyperfine coupling (Kevan & Kispert, 1976, section 1.4.3).…”

Section: Translates Into a Linementioning

confidence: 83%

Electron nuclear double resonance (ENDOR) of the Qc.cntdot.- ubisemiquinone radical in the mitochondrial electron transport chain

Salerno¹,

Osgood²,

Liu³

et al. 1990

Biochemistry

View full text Add to dashboard Cite

We present an electron nuclear double resonance (ENDOR) study of the bound Qc.- ubisemiquinone in the mitochondrial quinol cytochrome c reductase complex. An ENDOR probe specifically modified for insertion into our electron paramagnetic resonance cavity was used for this study. We observed strongly hyperfine-coupled protons whose exchangeable nature indicated they were hydrogen-bonded to the quinone oxygen(s). It is thought that such hydrogen bonds are critical in binding the ubiquinone to protein, in stabilizing its semiquinone form, and in modulating the thermodynamic properties of the bound ubiquinone in the mitochondrial quinol cytochrome c reductase complex. Additional ENDOR features were assigned to protons of the quinone ring itself and to weakly coupled protons that may be associated with nearby amino acids. From very weakly hyperfine-coupled, distant, exchangeable protons there was also ENDOR evidence to suggest proximity and accessibility of the ubiquinone site to the solvent.

show abstract

“…Dioxygen activation is one of the major functions of biological metal centers, and ENDOR spectroscopy has been used to study heme, nonheme iron (27), diiron (28), and noniron dioxygen-activating enzymes (29). Heme oxygenations in particular are perhaps the most widely studied bioinorganic reactions: during the 1990s, roughly one paper on cytochromes P450 alone was published every five hours (Martin Newcomb, personal communication).…”

Section: Dioxygen Activation By Heme Enzymesmentioning

confidence: 99%

Electron-nuclear double resonance spectroscopy (and electron spin-echo envelope modulation spectroscopy) in bioinorganic chemistry

Hoffman

2003

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

View full text Add to dashboard Cite

This perspective discusses the ways that advanced paramagnetic resonance techniques, namely electron-nuclear double resonance (ENDOR) and electron spin-echo envelope modulation (ESEEM) spectroscopies, can help us understand how metal ions function in biological systems.T he invitation to write this article explained, ''Perspective articles are intended to survey, from the author's distinctive perspective, some frontier aspects of the featured field and to highlight important recent developments and challenges.'' Within that definition, I shall discuss the ways that advanced paramagnetic resonance techniques, namely electron-nuclear double resonance (ENDOR) spectroscopy (1) and its junior partner electron spin-echo envelope modulation (ESEEM) spectroscopy (2), help us understand how metal ions function in biological systems and provide information in all of the critical categories listed in Table 1. In these early days of proteomics, where the primary sequence of all proteins in an organism are knowable in principle, and increasingly in fact, and where large-scale efforts are under way to determine the resting-state x-ray crystal structures of these proteins, this article is a representative response to the broader question: what roles do spectroscopies play? The answer, of course, is many, and important ones. BackgroundKey information about the composition, bonding, and structure of a paramagnetic metal center can be obtained by analysis of the electron-nuclear hyperfine and nuclear quadrupole couplings (3) of nuclei associated with endogenous and exogenous metal ligands, enzymebound substrates, inhibitors, and products, as well as the metal ions themselves. In principle, these couplings can be derived from splittings observable in a center's EPR spectrum. For most metallo-biomolecules, however, a variety of factors make these interactions unresolvable for most (or any) nuclei, and the chemical information is lost.ENDOR and ESEEM spectroscopies (3-7) retrieve the missing information. They provide an NMR spectrum of those nuclei that interact with the electron spin of the paramagnetic center, and such spectra display orders-ofmagnitude-better resolution than the

show abstract

Electron nuclear double resonance of cytochrome oxidase: Nitrogen and proton endor from the ‘copper’ EPR signal

Cited by 37 publications

References 21 publications

Copper electron-nuclear double resonance of cytochrome c oxidase.

Copper electron-nuclear double resonance of cytochrome c oxidase.

Electron nuclear double resonance (ENDOR) of the Qc.cntdot.- ubisemiquinone radical in the mitochondrial electron transport chain

Electron-nuclear double resonance spectroscopy (and electron spin-echo envelope modulation spectroscopy) in bioinorganic chemistry

Contact Info

Product

Resources

About