Evolution of Rhodopseudomonas palustris to degrade halogenated aromatic compounds involves changes in pathway regulation and enzyme specificity.

, encodes all the enzymes required for degradation of a halogenated aromatic compound, it is unable to metabolize that compound. Using adaptive evolution, we found that a regulatory mutation and a variant of promiscuous enzyme with increased substrate specificity were required. This work provides insight into how an environmental isolate evolved to use a halogenated aromatic compound.