Anion binding to oxidized type 2 depleted and native laccase: A spectroscopically effective model for exogenous ligand binding to the type 3 - type 2 active site

Abstract

Chemical and spectroscopic comparison of anion binding to the oxidized type 3 sites in type 2 depleted and native Rhus vernicifera laccase demonstrates that the type 3 - type 2 active site of laccase has an especially high affinity for exogenous ligands. N 3 − , O 2 2− and F − binding and competition, and resonance Raman studies, indicate that this high affinity is not due to strong, equatorial type 2 ligation, but rather to a structurally non-specific role of the type 2 copper in stabilizing anion binding at the type 3 binuclear cupric site. These studies, combined with previous results on half met type 2 depleted laccase, generate a spectroscopically effective model for peroxide birding to the type 3 - type 2 active site.