Food Science and Technology Department


Date of this Version

September 1998


Published in APPLIED AND ENVIRONMENTAL MICROBIOLOGY, Sept. 1998, p. 3147–3152 Vol. 64, No. 9. Copyright © 1998, American Society for Microbiology. All Rights Reserved. Used by permission.


The phosphoenolpyruvate (PEP)-dependent phosphotransferase system (PTS) utilizes high-energy phosphate present in PEP to drive the uptake of several different carbohydrates in bacteria. In order to examine the role of the PTS in the physiology of Listeria monocytogenes, we identified the ptsH and ptsI genes encoding the HPr and enzyme I proteins, respectively, of the PTS. Nucleotide sequence analysis indicated that the predicted proteins are nearly 70% similar to HPr and enzyme I proteins from other organisms. Purified L. monocytogenes HPr overexpressed in Escherichia coli was also capable of complementing an HPr defect in heterologous extracts of Staphylococcus aureus ptsH mutants. Additional studies of the transcriptional organization and control indicated that the ptsH and ptsI genes are organized into a transcription unit that is under the control of a consensus-like promoter and that expression of these genes is mediated by glucose availability and pH or by by-products of glucose metabolism.

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