Rationalizing the Right Ratios.
The three hydroxamate siderophores, avaroferrin, bisucaberin, and putrebactin are synthesized by the same key enzyme AvbD. Rütschlin et al. (2017) show that the ratio of these three compounds is not governed by the enzyme's substrate specificity but rather by the substrate pool. This ensures a large metabolic flexibility and adaptability to new environments.