Cloning and characterization of Escherichia coli DUF299: A bifunctional ADP-dependent kinase - Pi-dependent pyrophosphorylase from bacteria

Abstract

Background. Phosphoenolpyruvate synthetase (PEPS; EC 2.7.9.2) catalyzes the synthesis of phosphoenolpyruvate from pyruvate in Escherichia coli when cells are grown on a three carbon source. It also catalyses the anabolic conversion of pyruvate to phosphoenolpyruvate in gluconeogenesis. A bioinformatics search conducted following the successful cloning and expression of maize leaf pyruvate, orthophosphate dikinase regulatory protein (PDRP) revealed the presence of PDRP homologs in more than 300 bacterial species; the PDRP homolog was identified as DUF299. Results. This paper describes the cloning and expression of both PEPS and DUF299 from E. coli and establishes that E. coli DUF299 catalyzes both the ADP-dependent inactivation and the P i-dependent activation of PEPS. Conclusion. This paper represents the first report of a bifunctional regulatory enzyme catalysing an ADP-dependent phosphorylation and a Pi-dependent pyrophosphorylation reaction in bacteria. © 2010 Burnell; licensee BioMed Central Ltd.