[Objective] Epoxide hydrolases (EHs) play a key role in the synthesis of chiral pharmaceuticals. We explored new EHs by engineering or gene retrieval, aiming to enrich and discover more high-performance EHs. [Methods] A novel epoxide hydrolase (Aspergillus carlsbadensis epoxide hydrolase, AcEH) from Aspergillus carlsbadensis was identified by gene retrieval technology. We then used AutoDock2 to predict the key hydrolysis sites of AcEH and employed computational design to clarify the influences of important sites on the structure and catalytic mechanism of AcEH. [Results] The primary structure of the novel EH had three characteristic α/β EH motifs: HGWP, GYTFS, and GGDIGS. AcEH exhibited high activity and could completely hydrolyze styrene oxide (SO) within 15 min, with a specific activity of 13 951 U/g. The Km, Vmax, and kcat/Km of AcEH were (107.07±57.98) mmol/L, (37.22±17.85) μmol/(min·mg), and 1.17 mmol/(L·s), respectively. The key hydrolysis sites of AcEH were Asp192-His372-Glu346, which catalyzed the triad, and two conserved tyrosine residues, Tyr251/314. The mutations R49L and R49Y caused enzyme inactivation, while the mutation Y45L resulted in the formation of inactive inclusion bodies. The interaction network revealed that changes in the 49th amino acid residue disrupted the interactions between key active site residues, leading to enzyme inactivation. On the other hand, the alteration of the 45th amino acid residue destabilized the enzyme structure, leading to the formation of inclusion bodies. [Conclusion] This study discovered a novel EH and analyzed its hydrolysis mechanism. The findings provide valuable insights for further research and engineering on this enzyme.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |