Functional and Structural Characterization of a Thermostable Phospholipase A(2) from a Sparidae Fish (Diplodus annularis)
Résumé
Novel phospholipase (PLA(2)) genes from the Sparidae family were cloned. The sequenced PLA(2) revealed an identity with pancreatic PLA(2) group IB. To better understand the structure/function relationships of these enzymes and their evolution, the Diplodus annularis PLA(2) (DaPLA(2)) was overexpressed in E. coli. The refolded enzyme was purified by Ni-affinity chromatography and has a molecular mass of 15 kDa as determined by MALDI-TOF spectrometry. Interestingly, unlike the pancreatic type, the DaPIA(2) was active and stable at higher temperatures, which suggests its great potential in biotechnological applications. The 31) structure of DaPLA(2) was constructed to gain insights into the functional properties of sparidae PLA(2). Molecular docking and dynamic simulations were performed to explain the higher thermal stability and the substrate specificity of DaPLA(2). Using the monolayer technique, the purified DaPLA(2) was found to be active on various phospholipids ranging from 10 to 20 mN-m(-1), which explained the absence of the hemolytic activity for DaPLA(2).