Structural and mechanistic investigations on Salmonella typhimurium acetate kinase (AckA): identification of a putative ligand binding pocket at the dimeric interface.

ABSTRACT:

Background

Bacteria such as Escherichia coli and Salmonella typhimurium can utilize acetate as the sole source of carbon and energy. Acetate kinase (AckA) and phosphotransacetylase (Pta), key enzymes of acetate utilization pathway, regulate flux of metabolites in glycolysis, gluconeogenesis, TCA cycle, glyoxylate bypass and fatty acid metabolism.

Results

Here we report kinetic characterization of S. typhimurium AckA (StAckA) and structures of its unliganded (Form-I, 2.70 Å resolution) and citrate-bound (Form-II, 1.90 Å resolution) forms. The enzyme showed broad substrate specificity with k(cat)/K(m) in the order of acetate > propionate > formate. Further, the Km for acetyl-phosphate was significantly lower than for acetate and the enzyme could catalyze the reverse reaction (

SUBMITTER: Chittori S 

PROVIDER: S-EPMC3475010 | biostudies-literature | 2012 Oct

REPOSITORIES: biostudies-literature