Copper-binding energetics of amicyanin in different folding states.

Amicyanin is a type I copper protein that mediates electron transfer between methylamine dehydrogenase and cytochrome c- for energy production in Paracoccus denitrificans. Although the Met98 axial ligand of amicyanin has been shown to dictate metal selectivity and specificity during protein folding, the mechanism involved in copper-mediated amicyanin folding is unknown. Here, we kinetically and spectroscopically described reaction steps for incorporating copper into fully and less folded apo-amicyanin and established thermodynamic parameters for two amicyanin folding states.