The native intermediate state of the small laccase persists for months at 4 °C and pH 7.
An isolated Type-3 copper site produces the 1H NMR spectrum of the resting oxidized state.
The site of three coupled Cu ions produces the 1H NMR spectrum of the native intermediate.
A method for calculating the chemical shifts in an oxidized Cu3 cluster is developed.
The energy of the quartet state supports the model of a hydroxo ligand at the Type-2 site.