Figure 4.

ICP–MS analysis of retentates obtained by ultrafiltration of LanP (Mfla_0908) incubated with different rare-earth elements.A, schematic illustration of the binding assay and the removal of unbound metals by centrifugal ultrafiltration. B–D, quantification of rare-earth elements in retentates by ICP–MS. In the negative control, no protein was present (blue bars). For the assays with protein (orange bars), 4 μM LanP was incubated with (B) 20 μM LaCl₃, (C) 100 μM LaCl₃ and 100 μM CaCl₂, and (D) 20 μM of each CeCl₃, LaCl₃, NdCl₃, YCl_3, and 10 μM PrCl₃. Each assay was repeated three times, and the error bars depict the standard deviation. ICP–MS, inductively coupled plasma mass spectrometry.