Resolving ligand hyperfine couplings of type 1 and 2 Cu(ii) in ascorbate oxidase by high field pulse EPRcorrelation spectroscopy

Abstract

Ascorbate oxidase contains two paramagnetic Cu(II) binding sites, type 1 (T1) and type 2 (T2) and in both sites the Cu(II) is coordinated to histidine residues. We use several pulse EPR techniques at high field (95 GHz) to determine ligand ¹H and ¹⁴N hyperfine couplings in the two sites and identify the T1 signals by a new triple resonance correlation technique named THYCOS.