Structural and kinetic characterization of Francisella tularensis acetate kinase

Francisella tularensis is the bacteria responsible for tularemia, or rabbit fever. Weaponized strains of F. tularensis were developed in the 1940's, and although all stockpiles of these strains were presumably destroyed, the bacterium still has the potential to be converted into a bioweapon. In order to treat weaponized strains, new targets and new treatments must be developed. To this end, we have characterized the acetate kinase from F. tularensis both structurally and kinetically. The acetate kinase gene was subcloned into a pProEX‐HTb expression vector, and was purified using a nickel‐affinity column. The structure of F. tularensis acetate kinase was determined to a resolution of 2.2 Å, and is similar to other known acetate and propionate kinases. The kinetic constants, k cat and K M, with acetate as the substrate were determined to be 363 s −1 and 14 mM, respectively. While the kinetic constants, k cat and K M , with propionate as the substrate were determined to be 66 s −1 and 75 mM, respectively. In addition, we utilized high‐throughput virtual screening to identify potential inhibitors of the acetate kinase, and we have demonstrated that the acetate kinase is amenable to inhibitor screening using a thermal stability assay. This research was funded by the Wabash College Byron K. Trippet Fund and the Haines Biochemistry Fund.