Synthesis of an acyl-acyl carrier protein synthetase inhibitor to study fatty acid recycling

Fatty acids are essential to most organisms and are made endogenously by the fatty acid synthase (FAS). FAS is an attractive target for antibiotics and many inhibitors are in clinical development. However, some gram-negative bacteria harbor an enzyme known as the acyl-acyl carrier protein synthetase (AasS), which allows them to scavenge fatty acids from the environment and shuttle them into FAS and ultimately lipids. The ability of AasS to recycle fatty acids may help pathogenic gram-negative bacteria circumvent FAS inhibition. We therefore set out to design and synthesize an inhibitor of AasS and test its effectiveness on an AasS enzyme from Vibrio harveyi, the most well studied AasS to date, and from Vibrio cholerae, a pathogenic model. The inhibitor C10-AMS [5′-O-(N-decanylsulfamoyl)adenosine], which mimics the tightly bound acyl-AMP reaction intermediate, was able to effectively inhibit AasS catalytic activity in vitro. Additionally, C10-AMS stopped the ability of Vibrio cholerae to recycle fatty acids from media and survive when its endogenous FAS was inhibited with cerulenin. C10-AMS can be used to study fatty acid recycling in other bacteria as more AasS enzymes continue to be annotated and provides a platform for potential antibiotic development.