In this study, we constructed a metal-binding site close to the heme cofactor in myoglobin (Mb) by covalently attaching a nonnative metal-binding ligand of bipyridine to Cys46 through the F46C mutation in the heme distal site. The X-ray structure of the designed enzyme, termed F46C-mBpy Mb, was solved in the Cu(II)-bound form, which revealed the formation of a heterodinuclear center of Cu-His-H(2)O-heme. Cu(II)-F46C-mBpy Mb exhibits not only nitrite reductase reactivity but also cascade reaction activity involving both hydrolysis and oxidation. Furthermore, F46C-mBpy Mb displays Mn-peroxidase ...
