FIG. 1.

Vanillate and many other plant products are metabolized through protocatechuate. The pob, qui, and pca genes are clustered in the Acinetobacter chromosome. The open box indicates protocatechuate, and the shaded box indicates carboxymuconate, which is produced by the action of protocatechuate 3,4-dioxygenase on protocatechuate. Arrows indicate metabolic reactions and are accompanied by the designations of genes encoding the enzymes that catalyze the reactions. Metabolic accumulation of carboxymuconate in strain ADP230, defective in pcaB, prevents the growth of cells in the presence of substrates that can be metabolized to carboxymuconate.