Understanding uranium-protein interaction is important for revealing the mechanism of uranyl ion (UO_2~(2+)) toxicity. In this study, we investigated the interaction between UO_2~(2+) and a quadruple mutant of cytochrome b5 (E44/48/56A/D60A cyt b_5, namely 4A cyt b_5) by spectroscopic approaches. The four mutated negatively-charged surface residues of cyt b_5 have been considered to be the interactive sites with cytochrome c (cyt c). Also, we studied the interaction between UO_1~(2+) and the protein-protein complex of 4A cyt b5-cyt c. The results were compared to the interaction between UO_2~(...
