Cloning,purification and properties of a hyperthermophilic esterase from archaeon Aeropyrum pernix K1

摘要

The gene APE1547 of the aerobic thermophilic Aeropyrum pernix K1 encoding 582 amino acid residues was cloned into Escherichia coli.BL21 (DE3) byusign vector pET11a with a T7 promoter.An alignment of similarity analysis of APE1547 with protein sequences fromA.pernix K1 databank revealed that it showed a lipase motif and low homoloyg with the known by ion exchange chromatography and gel filtration chromatography, the recombinant protein showed both esterase activity and acylamino acid-releasing enzyme (AARE) activities.The optimum of temperature and pH of theesterase activity are 90 deg C adn 8.0,respectively.The recombinant protein showe dthe hydropytic activity for a wide range of substrates,such as p-nitrophenyl alkanoate esters of varying alkyl chain lengths,pNA-labelled amino acid and peptide.The highest activity was observed for the substrate p-nitrophenyl caprylate. The recombinant enzyme was extremely stable and protein concentration-dependent. Its half-life at 90 deg C was over 160h.at the concentration of 2.14 mg/ml,which renders this new esterase very attractive for biotechnological applications.