Figure 4.

Native mass spectra of Staphylococcus aureus (Sa) cobalt and nickel transporter (Cnt) A protein. CntA is an extracytoplasmic nickel-binding subunit of an ABC-importer. A: Apo form of SaCntA analyzed at high collision energy (i.e., E: 140 Vs).⁵⁶ The 300–500 and 3500–5000 m/z ranges are shown. B: SaCntA, incubated with culture supernatant, was studied at the collision energy of 140 Vs. C: Expanded views of the 380–395 and 4050–4200 m/z ranges. The left view illustrates the isotopic pattern of the nickel-binding ligand. The right view shows the presence of two peaks corresponding to the apo and liganded SaCntA. Empty circles, apo SaCntA; filled circles, liganded SaCntA; asterisk, Ni(II)-containing ligand.