Molecular Investigation of Iron–Sulfur Cluster Assembly Scaffolds under Stress

Abstract

Fe/S biosynthesis is controlled in <i>Escherichia coli</i> by two machineries, the housekeeping ISC machinery and the SUF system that is functional under stress conditions. Despite many <i>in vivo</i> studies showing that SUF is more adapted for Fe/S assembly under stress, no molecular data supporting this concept have been provided so far. This work focuses on molecular studies of key actors in Fe/S assembly, the SufB and IscU scaffolds under oxidative stress and iron limitation. We show that the IscU Fe₂S₂ cluster is less stable than the SufB Fe₂S₂ cluster in the presence of hydrogen peroxide, oxygen, and an iron chelator