Bzdrenga Janek, Hiblot Julien, Gotthard Guillaume, Champion Charlotte, Elias Mikael, Chabriere Eric
URMITE UMR CNRS-IRD 6236, IFR48, Faculté de Médecine et de Pharmacie, Université de la Méditerranée, Marseille, France.
BMC Res Notes. 2014 Jun 3;7:333. doi: 10.1186/1756-0500-7-333.
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.
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.
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.
SacPox是一种来自嗜热泉古菌嗜酸热硫化叶菌（Sac）的酶，因其磷酸三酯酶（或对氧磷酶；Pox）活性，即水解神经毒性有机磷杀虫剂的能力而被分离出来。后来发现，SacPox属于磷酸三酯酶样内酯酶家族，该家族包含可能参与群体感应且具有混杂磷酸三酯酶活性的天然内酯酶。
在此，我们对SacPox的天然内酯酶和混杂有机磷水解酶活性进行了全面且广泛的酶学表征，并使用模型进行了结构分析。
动力学实验表明，SacPox是一种高效的内酯酶，在室温下也是如此。此外，我们讨论了SacPox与其最接近的同系物SsoPox和SisLac之间在底物特异性上观察到的差异以及这些观察结果可能的结构原因。
