Novel phospholipase (PLA2) genes from the Sparidae family were cloned. The sequenced PLA2 revealed an identity with pancreatic PLA2 group IB. To better understand the structure/function relationships of these enzymes and their evolution, the Diplodus annularis PLA2 (DaPLA2) 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 DaPLA2 was active and stable at higher temperatures, which suggests its great potential in biotechnological applications. The 3D structure of DaPLA2 was constructed to gain insights into the functional properties of sparidae PLA2. Molecular docking and dynamic simulations were performed to explain the higher thermal stability and the substrate specificity of DaPLA2. Using the monolayer technique, the purified DaPLA2 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 DaPLA2.
Keywords: E. coli expression; Sparidae; monolayer properties; phospholipase A2; refolding and purification; structural characterization; thermostability.