Figure 4.

The conserved cysteine residues in the E. coli Fur are the ligands for the [2Fe-2S] cluster. The Fur mutant proteins were constructed by the site-directed mutagenesis and purified from the E. coli iscA/sufA mutant cells. A, UV-visible absorption spectra of the WT Fur (spectrum 1), the mutant H190A (spectrum 2), and the mutant E108A (spectrum 3). B, UV-visible absorption spectra of the WT Fur (spectrum 1), the mutant C93A (spectrum 2), the mutant C96A (spectrum 3), and the mutant C133A (spectrum 4). Each spectrum was offset for clarity. The protein concentrations were ∼100 μm. The results are representative of three independent experiments.