Fig 9. Sulfur transfer and Fe-S cluster biosynthesis assays of BsSufS and BsSufU in the presence of BsFra.

(A) The specific activity of BsSufS was measured in vitro by the release of sulfide from cysteine. The activity of BsSufS (green) is unaffected by BsFra (cyan), but is greatly increased by the presence of BsSufU (red). The addition of BsFra to BsSufS/BsSufU does not affect the activity of BsSufS. (B) In vitro biogenesis of Fe-S clusters by BsSufS/BsSufU over time (red). Addition of BsFra (blue) results in a very slight increase in cluster yield.