Identification of a regulated alkaline phosphatase, a cell surface-associated lipoprotein, in Mycobacterium smegmatis

Jordan Kriakov, Sun Hee Lee, William R. Jacobs

Research output: Contribution to journalArticle

25 Scopus citations


Although alkaline phosphatases are common in a wide variety of bacteria, there has been no prior evidence for alkaline phosphatases in Mycobacterium smegmatis. Here we report that transposon insertions in the pst operon, encoding homologues of an inorganic phosphate transporter, leads to constitutive expression of a protein with alkaline phosphatase activity. DNA sequence analysis revealed that M. smegmatis does indeed have a phoA gene that shows high homology to other phoA genes. The M. smegmatis phoA gene was shown to be induced by phosphate starvation and thus negatively regulated by the pst operon. Interestingly, the putative M. smegmatis PhoA has a hydrophobic N-terminal domain which resembles a lipoprotein signal sequence. The M. smegmatis PhoA was demonstrated to be an exported protein associated with the cell surface. Furthermore, immunoprecipitation of PhoA from [14C]acetate-labeled M. smegmatis cell lysates demonstrated that this phosphatase is a lipoprotein.

Original languageEnglish (US)
Pages (from-to)4983-4991
Number of pages9
JournalJournal of Bacteriology
Issue number16
StatePublished - Aug 1 2003


ASJC Scopus subject areas

  • Microbiology
  • Molecular Biology

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