Figure 6.
Evidence that 1:1 Cu(I) to protein species are mononuclear. Top panel, comparison of Fourier transforms of the Se EXAFS of the M160SeM species at Cu(I) to protein ratios of 1:1 and 2:1 showing near equivalency of the intensity of the Se-Cu peaks in the FT expected for a mononuclear Cu(I) species. Bottom panel, absorption edges of Cu(I) mononuclear species compared with the 3-coordinate Cu(I) derivative of the H135A variant of B. subtilis Sco (where Cu(I) is bound by 2 Cys and 1 Met residue). The low intensity of the 8983 eV peaks of the mononuclear Cu(I) CuA intermediates suggest 4-coordination.