Analysis of Escherichia coli TonB membrane topology by use of PhoA fusions

S. K. Roof, J. D. Allard, K. P. Bertrand, K. Postle

Research output: Contribution to journalComment/debate

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Alkaline phosphatase (PhoA) fusions to TonB amino acids 32, 60, 125, 207, and 239 (the carboxy terminus) all showed high PhoA activity; a PhoA fusion to TonB amino acid 12 was inactive. The full-length TonB-PhoA fusion protein was associated with the cytoplasmic membrane and retained partial TonB function. These results support a model in which TonB is anchored in the cytoplasmic membrane by its hydrophobic amino terminus, with the remainder of the protein, including its hydrophobic carboxy terminus, extending into the periplasm.

Original languageEnglish (US)
Pages (from-to)5554-5557
Number of pages4
JournalJournal of bacteriology
Issue number17
StatePublished - Jan 1 1991


All Science Journal Classification (ASJC) codes

  • Microbiology
  • Molecular Biology

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