Biochemical characterization of phosphoryl transfer involving HPr of the phosphoenolpyruvate-dependent phosphotransferase system in Treponema denticola, an organism that lacks PTS permeases

Biochemistry. 2005 Jan 18;44(2):598-608. doi: 10.1021/bi048412y.


Treponema pallidum and Treponema denticola encode within their genomes homologues of energy coupling and regulatory proteins of the phosphoenolpyruvate:sugar phosphotransferase system (PTS) but no recognizable homologues of PTS permeases. These homologues include (1) Enzyme I, (2) HPr, (3) two IIA(Ntr)-like proteins, and (4) HPr(Ser) kinase/phosphorylase (HprK). Because the Enzyme I-encoding gene in T. pallidum is an inactive pseudogene and because all other pts genes in both T. pallidum and T. denticola are actively expressed, the primary sensory transduction mechanism for signal detection and transmission appears to involve HprK rather than EI. We have overexpressed and purified to near homogeneity four of the five PTS proteins from T. denticola. Purified HprK phosphorylates HPr with ATP, probably on serine, while Enzyme I phosphorylates HPr with PEP, probably on histidine. Furthermore, HPr(His)-P can transfer its phosphoryl group to IIA(Ntr)-1. Factors and conditions regulating phosphoryl transfer prove to differ from those described previously for Bacillus subtilis, but cross-enzymatic activities between the Treponema, Salmonella, and Bacillus phosphoryl-transfer systems could be demonstrated. Kinetic analyses revealed that the allosterically regulated HPr kinase/phosphorylase differs from its homologues in Bacillus subtilis and other low G+C Gram-positive bacteria in being primed for kinase activity rather than phosphorylase activity in the absence of allosteric effectors. The characteristics of this enzyme and the Treponema phosphoryl-transfer chain imply unique modes of signal detection and sensory transmission. This paper provides the first biochemical description of PTS phosphoryl-transfer chains in an organism that lacks PTS permeases.

Publication types

  • Comparative Study
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adenosine Triphosphate / metabolism
  • Amino Acid Sequence
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism
  • Escherichia coli Proteins / metabolism
  • Genetic Complementation Test
  • Molecular Sequence Data
  • Phosphate Transport Proteins / deficiency*
  • Phosphate Transport Proteins / genetics
  • Phosphoenolpyruvate Sugar Phosphotransferase System / chemistry*
  • Phosphoenolpyruvate Sugar Phosphotransferase System / genetics
  • Phosphoenolpyruvate Sugar Phosphotransferase System / isolation & purification
  • Phosphoenolpyruvate Sugar Phosphotransferase System / metabolism*
  • Phosphorus Radioisotopes / metabolism
  • Phosphorylation
  • Phosphotransferases (Nitrogenous Group Acceptor) / chemistry*
  • Phosphotransferases (Nitrogenous Group Acceptor) / genetics
  • Phosphotransferases (Nitrogenous Group Acceptor) / metabolism*
  • Protein-Serine-Threonine Kinases / chemistry*
  • Protein-Serine-Threonine Kinases / genetics
  • Protein-Serine-Threonine Kinases / metabolism*
  • Sequence Alignment
  • Treponema denticola / enzymology*
  • Treponema denticola / genetics
  • Treponema pallidum / enzymology
  • Treponema pallidum / genetics


  • Bacterial Proteins
  • Escherichia coli Proteins
  • Phosphate Transport Proteins
  • Phosphorus Radioisotopes
  • phosphate permease
  • Adenosine Triphosphate
  • IIA(Ntr) protein, E coli
  • Phosphoenolpyruvate Sugar Phosphotransferase System
  • phosphocarrier protein HPr
  • HPr kinase
  • Protein-Serine-Threonine Kinases
  • Phosphotransferases (Nitrogenous Group Acceptor)
  • phosphoenolpyruvate-protein phosphotransferase