Physiological and biochemical analysis of the effects of alkaline phosphatase overproduction in Escherichia coli

H. Kadokura, K. Watanabe, K. Tsuneizumi, K. Yoda, M. Yamasaki

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)

Abstract

Overexpression of the Escherichia coli phoA gene, coding for alkaline phosphatase (PhoA), on multicopy plasmids caused a severe defect in the precursor processing (secretion) of PhoA, β-lactamase, and the outer membrane protein OmpA. This secretion defect continued even after the repression of phoA expression, indicating that protein secretion was irreversibly impaired in cells. Among the secretary proteins, only OmpA gradually secreted posttranslationally. The inverted inner membrane vesicles prepared from cells with the secretion defect showed appreciably reduced translocation activity in vitro. But the membrane vesicles retained the ability to generate a proton motive force which, together with ATP, is essential as an energy source for the efficient secretion of proteins in E. coli. An appreciable amount of incompletely translocated PhoA molecules was detected in the inner membranes of cells with the secretion defect.

Original languageEnglish
Pages (from-to)3596-3600
Number of pages5
JournalJournal of bacteriology
Volume177
Issue number12
DOIs
Publication statusPublished - 1995

ASJC Scopus subject areas

  • Microbiology
  • Molecular Biology

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