title: The general PTS component HPr determines the preference for glucose over mannitol.
abstract: Preferential sugar utilization is a widespread phenomenon in biological systems. Glucose is usually the most preferred carbon source in various organisms, especially in bacteria where it is taken up via the phosphoenolpyruvate:sugar phosphotransferase system (PTS). The currently proposed model for glucose preference over non-PTS sugars in enteric bacteria including E. coli is strictly dependent on the phosphorylation state of the glucose-specific PTS component, enzyme IIAGlc(EIIAGlc). However, the mechanism of the preference among PTS sugars is largely unknown in Gram-negative bacteria. Here, we show that glucose preference over another PTS sugar, mannitol, is absolutely dependent on the general PTS component HPr, but not on EIIAGlc, in E. coli. Dephosphorylated HPr accumulates during the transport of glucose and interacts with the mannitol operon regulator, MtlR, to augment its repressor activity. This interaction blocks the inductive effect of mannitol on the mannitol operon expression and results in the inhibition of mannitol utilization.
authors.affiliation: School of Biological Sciences and Institute of Microbiology, Seoul National University, Seoul 00826, Korea.
authors.forename: Mangyu
authors.initials: M
authors.lastname: Choe
authors.affiliation: School of Biological Sciences and Institute of Microbiology, Seoul National University, Seoul 00826, Korea.
authors.forename: Young-Ha
authors.initials: YH
authors.lastname: Park
authors.affiliation: Department of Biological Sciences, Myongji University, Yongin, Gyeonggido 17058, Republic of Korea.
authors.forename: Chang-Ro
authors.initials: CR
authors.lastname: Lee
authors.affiliation: School of Biological Sciences and Institute of Microbiology, Seoul National University, Seoul 00826, Korea.
authors.forename: Yeon-Ran
authors.initials: YR
authors.lastname: Kim
authors.affiliation: School of Biological Sciences and Institute of Microbiology, Seoul National University, Seoul 00826, Korea.
authors.forename: Yeong-Jae
authors.initials: YJ
authors.lastname: Seok
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D001692:Biological Transport; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000235:genetics* / Q000378:metabolism; D005285:Fermentation; D015964:Gene Expression Regulation, Bacterial; D005947:Glucose / Q000378:metabolism*; D008353:Mannitol / Q000378:metabolism*; D009876:Operon; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System / Q000235:genetics* / Q000378:metabolism; D010766:Phosphorylation; D012097:Repressor Proteins / Q000235:genetics* / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; C085654:MtlR protein, E coli; D012097:Repressor Proteins; C032242:crr protein, E coli; D008353:Mannitol; D010731:Phosphoenolpyruvate Sugar Phosphotransferase System; C030182:phosphocarrier protein HPr; D005947:Glucose