Cloning of the Gene and Characterization of the Enzymatic Properties of the Monomeric Alkaline Phosphatase (PhoX) From Pasteurella Multocida Strain X-73

FEMS Microbiol Lett. 2007 Feb;267(1):113-20. doi: 10.1111/j.1574-6968.2006.00542.x. Epub 2006 Nov 29.


We have identified a new phoX gene encoding the monomeric alkaline phosphatase from Pasteurella multocida X-73. This gene was not found in the published genome sequence of Pasteurella multocida pm70. Characterization of the recombinant PhoX of Pasteurella multocida X-73 showed that it is a monomeric enzyme, activated by Ca(2+) and possibly secreted by the Tat pathway. These features distinguish phosphatases of the PhoX family from those of the PhoA family. All proteins of the PhoX family were found to contain a conserved motif that shares significant sequence homology with the calcium-binding site of a phosphotriesterase known as diisopropylfluorophosphatase. Site-directed mutagenesis revealed that D527 of PhoX might be the ligand bound to the catalytic calcium. This is the first report on identification of homologous sequences between PhoX and the phosphotriesterase and on the potential calcium-binding site of PhoX.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alkaline Phosphatase / chemistry
  • Alkaline Phosphatase / genetics*
  • Alkaline Phosphatase / metabolism*
  • Amino Acid Sequence
  • Amino Acid Substitution
  • Base Sequence
  • Binding Sites / genetics
  • Calcium / pharmacology
  • Cloning, Molecular
  • Conserved Sequence
  • DNA, Bacterial / chemistry
  • DNA, Bacterial / genetics
  • Enzyme Activators / pharmacology
  • Ligands
  • Molecular Sequence Data
  • Mutagenesis, Site-Directed
  • Pasteurella multocida / enzymology*
  • Pasteurella multocida / genetics*
  • Protein Subunits
  • Recombinant Proteins / metabolism
  • Sequence Analysis, DNA


  • DNA, Bacterial
  • Enzyme Activators
  • Ligands
  • Protein Subunits
  • Recombinant Proteins
  • Alkaline Phosphatase
  • Calcium

Associated data

  • GENBANK/DQ986289