DesT Coordinates the Expression of Anaerobic and Aerobic Pathways for Unsaturated Fatty Acid Biosynthesis in Pseudomonas aeruginosa

The fabA and fabB genes are responsible for anaerobic unsaturated fatty acid formation in Pseudomonas aeruginosa. Expression of the fabAB operon was repressed by exogenous unsaturated fatty acids, and DNA sequences upstream of the translational start site were used to affinity purify DesT. The single protein interaction with the fabAB promoter detected in wild-type cell extracts was absent in the desT deletion strain, as was the repression of fabAB expression by unsaturated fatty acids. Thus, DesT senses the overall composition of the acyl-coenzyme A pool to coordinate the expression of the operons for the anaerobic (fabAB) and aerobic (desCB) pathways for unsaturated fatty acid synthesis.