title: Histidine phosphocarrier protein regulates pyruvate kinase A activity in response to glucose in Vibrio vulnificus.
abstract: The bacterial phosphoenolpyruvate:sugar phosphotransferase system (PTS) consists of two general energy-coupling proteins [enzyme I and histidine phosphocarrier protein (HPr)] and several sugar-specific enzyme IIs. Although, in addition to the phosphorylation-coupled transport of sugars, various regulatory roles of PTS components have been identified in Escherichia coli, much less is known about the PTS in the opportunistic human pathogen Vibrio vulnificus. In this study, we have identified pyruvate kinase A (PykA) as a binding partner of HPr in V. vulnificus. The interaction between HPr and PykA was strictly dependent on the presence of inorganic phosphate, and only dephosphorylated HPr interacted with PykA. Experiments involving domain swapping between the PykAs of V. vulnificus and E. coli revealed the requirement for the C-terminal domain of V. vulnificus PykA for a specific interaction with V. vulnificus HPr. Dephosphorylated HPr decreased the Km of PykA for phosphoenolpyruvate by approximately fourfold without affecting Vmax . Taken together, these findings indicate that the V. vulnificus PTS catalyzing the first step of glycolysis stimulates the final step of glycolysis in the presence of glucose through the direct interaction of dephospho-HPr with the C-terminal domain of PykA.
authors.affiliation: Department of Biological Sciences and Institute of Microbiology, Seoul National University, Seoul, 151-742, South Korea.
authors.forename: Hey-Min
authors.initials: HM
authors.lastname: Kim
authors.forename: Young-Ha
authors.initials: YH
authors.lastname: Park
authors.forename: Chang-Kyu
authors.initials: CK
authors.lastname: Yoon
authors.forename: Yeong-Jae
authors.initials: YJ
authors.lastname: Seok
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D005947:Glucose / Q000378:metabolism*; D006639:Histidine / Q000378:metabolism; D006801:Humans; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D011770:Pyruvate Kinase / Q000235:genetics / Q000378:metabolism*; D014735:Vibrio Infections / Q000382:microbiology*; D041261:Vibrio vulnificus / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D006639:Histidine; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System; C030182:phosphocarrier protein HPr; D011770:Pyruvate Kinase; D005947:Glucose