Multi-frequency e.p.r. studies of a mercury-containing mixed-metal derivative of laccase. Biochem J 1986 Apr 15;235(2):415-20
Date
04/15/1986Pubmed ID
3017305Pubmed Central ID
PMC1146702DOI
10.1042/bj2350415Scopus ID
2-s2.0-0023049397 (requires institutional sign-in at Scopus site) 26 CitationsAbstract
Multi-frequency e.p.r. studies of a derivative of laccase containing one mercury atom and three of copper were carried out at -150 degrees C. The e.p.r. signal of the mercury derivative and fluoride-binding studies establish that a type-2-like copper centre is present. The signal suffers broadening, owing to g-strain, but at low frequencies (S-band) ligand hyperfine splitting can be resolved, and it can be explained in terms of coupling to three nitrogen atoms. The g values and the effect of solvent deuteration on the line width suggest that the fourth ligand in the equatorial plane is a water molecule. Simulations of the e.p.r. spectrum reveal that the site is slightly rhombic at -150 degrees C, a finding in accord with the proposed N3O donor set. Finally, it is emphasized that a structural reorganization of the type-2 copper site occurs with the binding of fluoride at low temperature. The reorganization may be linked to a conformational change which has previously been claimed to occur on cooling; however, this transition is not necessarily relevant to the temperature-dependence of fluoride binding.
Author List
Morie-Bebel MM, McMillin DR, Antholine WEMESH terms used to index this publication - Major topics in bold
Binding SitesCopper
Electron Spin Resonance Spectroscopy
Fluorides
Laccase
Mercury
Oxidoreductases
Temperature