SacPox from the thermoacidophilic crenarchaeon Sulfolobus acidocaldarius is a proficient lactonase

BMC Res Notes. 2014 Jun 3;7:333. doi: 10.1186/1756-0500-7-333.


Background: SacPox, an enzyme from the extremophilic crenarchaeal Sulfolobus acidocaldarius (Sac), was isolated by virtue of its phosphotriesterase (or paraoxonase; Pox) activity, i.e. its ability to hydrolyze the neurotoxic organophosphorus insecticides. Later on, SacPox was shown to belong to the Phosphotriesterase-Like Lactonase family that comprises natural lactonases, possibly involved in quorum sensing, and endowed with promiscuous, phosphotriesterase activity.

Results: Here, we present a comprehensive and broad enzymatic characterization of the natural lactonase and promiscuous organophosphorus hydrolase activities of SacPox, as well as a structural analysis using a model.

Conclusion: Kinetic experiments show that SacPox is a proficient lactonase, including at room temperature. Moreover, we discuss the observed differences in substrate specificity between SacPox and its closest homologues SsoPox and SisLac together with the possible structural causes for these observations.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Kinetics
  • Molecular Sequence Data
  • Phosphoric Triester Hydrolases / chemistry
  • Phosphoric Triester Hydrolases / metabolism*
  • Phylogeny
  • Sequence Homology, Amino Acid
  • Sulfolobus acidocaldarius / enzymology*


  • Phosphoric Triester Hydrolases