The rhodanese RhdA helps Azotobacter vinelandii in maintaining cellular redox balance
AbstractThe tandem domain rhodanese-homology protein RhdA ofAzotobacter vinelandiishows an active-site loop structure that confers structural peculiarity in the environment of its catalytic cysteine residue. Thein vivoeffects of the lack of RhdA were investigated using anA. vinelandiimutant strain (MV474) in which therhdAgene was disrupted by deletion. Here, by combining analytical measurements and transcript profiles, we show that deletion of therhdAgene generates an oxidative stress condition to whichA. vinelandiiresponds by activating defensive mechanisms. In conditions of growth in the presence of the superoxide generator phenazine methosulfate, a stressor-dependent induction ofrhdAgene expression was observed, thus highlighting that RhdA is important forA. vinelandiito sustain oxidative stress. The potential of RhdA to buffer general levels of oxidants inA. vinelandiicells via redox reactions involving its cysteine thiol is discussed.