The OmpR protein of Escherichia coli binds to sites in the ompF promoter region in a hierarchical manner determined by its degree of phosphorylation

Arfaan Rampersaud, Susan L. Harlocker, Masayori Inouye

Research output: Contribution to journalArticle

72 Citations (Scopus)

Abstract

In Escherichia coli the ompF gene encodes a major outer membrane porin protein that is differentially regulated by the OmpR protein. OmpR acts as a positive as well as a negative regulator of ompF expression by binding to DNA sequences in the ompF promoter region. The DNA binding activity of OmpR is itself regulated by phosphorylation through the kinase protein EnvZ. Phosphorylation is believed to change the function of OmpR from an activator to a repressor molecule. By using purified OmpR and various regions of the ompF promoter we show that phosphorylation causes binding of OmpR to a DNA region between the -40 to -100 region of the ompF promoter previously shown to be important for ompF expression. As the amount of OmpR-phosphate increases, a binding site located at a further upstream -360 to -380 region was occupied. This latter site has been reported to be important for ompF repression. Further experiments indicate that the -70 to -100 region is a high affinity site, while the -45 to -60 and -360 to -380 regions are low affinity sites. We also provide evidence that OmpR binding at the -360 to - 380 region requires previous binding at downstream sequences, which is indicative of long range interactions between OmpR molecules. We interpret our results in terms of a model for ompF regulation involving hierarchical binding by phosphorylated OmpR and potential DNA looping.

Original languageEnglish (US)
Pages (from-to)12559-12566
Number of pages8
JournalJournal of Biological Chemistry
Volume269
Issue number17
StatePublished - Apr 29 1994

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Phosphorylation
Escherichia coli Proteins
Genetic Promoter Regions
DNA
Activator Appliances
Repressor Proteins
Porins
DNA sequences
Protein Kinases
Escherichia coli
Membrane Proteins
Proteins
Genes
Phosphates
Binding Sites
Membranes
Molecules
Experiments

All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Molecular Biology
  • Cell Biology

Cite this

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title = "The OmpR protein of Escherichia coli binds to sites in the ompF promoter region in a hierarchical manner determined by its degree of phosphorylation",
abstract = "In Escherichia coli the ompF gene encodes a major outer membrane porin protein that is differentially regulated by the OmpR protein. OmpR acts as a positive as well as a negative regulator of ompF expression by binding to DNA sequences in the ompF promoter region. The DNA binding activity of OmpR is itself regulated by phosphorylation through the kinase protein EnvZ. Phosphorylation is believed to change the function of OmpR from an activator to a repressor molecule. By using purified OmpR and various regions of the ompF promoter we show that phosphorylation causes binding of OmpR to a DNA region between the -40 to -100 region of the ompF promoter previously shown to be important for ompF expression. As the amount of OmpR-phosphate increases, a binding site located at a further upstream -360 to -380 region was occupied. This latter site has been reported to be important for ompF repression. Further experiments indicate that the -70 to -100 region is a high affinity site, while the -45 to -60 and -360 to -380 regions are low affinity sites. We also provide evidence that OmpR binding at the -360 to - 380 region requires previous binding at downstream sequences, which is indicative of long range interactions between OmpR molecules. We interpret our results in terms of a model for ompF regulation involving hierarchical binding by phosphorylated OmpR and potential DNA looping.",
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The OmpR protein of Escherichia coli binds to sites in the ompF promoter region in a hierarchical manner determined by its degree of phosphorylation. / Rampersaud, Arfaan; Harlocker, Susan L.; Inouye, Masayori.

In: Journal of Biological Chemistry, Vol. 269, No. 17, 29.04.1994, p. 12559-12566.

Research output: Contribution to journalArticle

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T1 - The OmpR protein of Escherichia coli binds to sites in the ompF promoter region in a hierarchical manner determined by its degree of phosphorylation

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AB - In Escherichia coli the ompF gene encodes a major outer membrane porin protein that is differentially regulated by the OmpR protein. OmpR acts as a positive as well as a negative regulator of ompF expression by binding to DNA sequences in the ompF promoter region. The DNA binding activity of OmpR is itself regulated by phosphorylation through the kinase protein EnvZ. Phosphorylation is believed to change the function of OmpR from an activator to a repressor molecule. By using purified OmpR and various regions of the ompF promoter we show that phosphorylation causes binding of OmpR to a DNA region between the -40 to -100 region of the ompF promoter previously shown to be important for ompF expression. As the amount of OmpR-phosphate increases, a binding site located at a further upstream -360 to -380 region was occupied. This latter site has been reported to be important for ompF repression. Further experiments indicate that the -70 to -100 region is a high affinity site, while the -45 to -60 and -360 to -380 regions are low affinity sites. We also provide evidence that OmpR binding at the -360 to - 380 region requires previous binding at downstream sequences, which is indicative of long range interactions between OmpR molecules. We interpret our results in terms of a model for ompF regulation involving hierarchical binding by phosphorylated OmpR and potential DNA looping.

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