Figure 9.
Apo/holo ratios of CopZs by alkylation-MS analysis. ΔcopZ complemented strains were cultured in the absence and presence of 0.5 mm CuSO4 during 10 min. A, CopZ1, and B, CopZ2, Cys were alkylated with maleimide and enriched protein preparations analyzed by MS/MS. The apo (white) and holo (black) ratios were quantified by summing the fragment intensity to obtain the molar fraction of modified versus nonmodified Cys in Cu-binding site-containing peptides. Data are the average of two independent experiments.