SacPox from the thermoacidophilic crenarchaeon Sulfolobus acidocaldarius is a proficient lactonase

摘要

Background Sac Pox, 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, Sac Pox 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 Sac Pox, as well as a structural analysis using a model. Conclusion Kinetic experiments show that Sac Pox is a proficient lactonase, including at room temperature. Moreover, we discuss the observed differences in substrate specificity between Sac Pox and its closest homologues Sso Pox and Sis Lac together with the possible structural causes for these observations.