Faculty Collaboration Database

Multiquantum EPR of the mixed valence copper site in nitrous oxide reductase. Biophys J 1993 May;64(5):1576-9

Date

05/01/1993

Pubmed ID

8391869

Pubmed Central ID

PMC1262484

DOI

10.1016/S0006-3495(93)81527-3

Scopus ID

2-s2.0-0027238621 (requires institutional sign-in at Scopus site)   21 Citations

Abstract

This work demonstrates the use of multiquantum EPR to study the magnetic properties of copper complexes and copper proteins. Pure absorption spectra are obtained because of the absence of field modulation. The signal intensity of 3-quantum spectra is proportional to the spin lattice relaxation time T1, while its linewidth in a frequency difference sweep is T1(-1). A change in lineshape for the EPR detectable mixed value [Cu(1.5) . . . Cu(1.5)] site in nitrous oxide reductase is attributed to suppression of the forbidden transitions. The data confirm the unusually fast relaxation time for this site, which requires temperatures of less than 100 K to resolve hyperfine structure. The T1's for the mixed valence [Cu(1.5) . . . Cu(1.5)] site in nitrous oxide reductase are very similar to T1's for the Cua site in cytochrome c oxidase. The similar relaxation properties, together with previous multifrequency EPR results, support the hypothesis that the EPR detectable sites in cytochrome c oxidase and nitrous oxide reductase are mixed valence [Cu(1.5) . . . Cu(1.5)] configurations.

Author List

Mchaourab HS, Pfenninger S, Antholine WE, Felix CC, Hyde JS, Kroneck PM

MESH terms used to index this publication - Major topics in bold

Binding Sites
Biophysical Phenomena
Biophysics
Copper
Electrochemistry
Electron Spin Resonance Spectroscopy
Electron Transport Complex IV
Oxidoreductases
Pseudomonas