6IX4

Structure of an epoxide hydrolase from Aspergillus usamii E001 (AuEH2) at 1.51 Angstroms resolution

Summary for 6IX4

• Entry DOI: 10.2210/pdb6ix4/pdb
• Descriptor: Microsomal epoxide hydrolase, ACETATE ION, GLYCEROL, ... (7 entities in total)
• Functional Keywords: alpha and beta proteins, alpha/beta-hydrolases, styrene oxide, hydrolase
• Biological source: Aspergillus usamii
• Total number of polymer chains: 2
• Total formula weight: 90077.02

Authors

Hu, D.,Hu, B.C.,Hou, X.D.,Wu, L.,Rao, Y.J.,Wu, M.C. (deposition date: 2018-12-09, release date: 2019-12-11, Last modification date: 2023-11-29)

Primary citation

Hu, D.,Hu, B.C.,Wen, Z.,Zhang, D.,Liu, Y.Y.,Zang, J.,Wu, M.C.
Nearly perfect kinetic resolution of racemic o-nitrostyrene oxide by AuEH2, a microsomal epoxide hydrolase from Aspergillus usamii, with high enantio- and regio-selectivity.
Int.J.Biol.Macromol., 169:1-7, 2021

PubMed Abstract: Only a few known epoxide hydrolases (EHs) displayed activity towards o-nitrostyrene oxide (4a), presumably owing to the large steric hindrance caused by o-nitro substituent. Therefore, excavating EHs with high activity and enantio- and/or regio-selectivity towards racemic (rac-) 4a is essential but challenging. Here, AuEH2 from Aspergillus usamii was expressed in E. coli BL21(DE3). E. coli/Aueh2, an E. coli transformant expressing AuEH2, possessed EH activities of 16.2-184 U/g wet cell towards rac-styrene oxide (1a) and its derivatives (2a-13a), and the largest enantiomeric ratio of 96 towards rac-4a. The regioselectivity coefficients, β and β, of AuEH2 were determined to be 99.2% and 98.9%, suggesting that it regiopreferentially attacks the C in the oxirane rings of (R)- and (S)-4a. Then, the nearly perfect kinetic resolution of 20 mM rac-4a in pure water was carried out using 20 mg/mL wet cells of E. coli/Aueh2 at 25 °C for 50 min, retaining (S)-4a with over 99% ee and 48.9% yield, while producing (R)-o-nitrophenyl-1,2-ethanediol (4b) with 95.3% ee and 49.8% yield. To elucidate the molecular mechanism of AuEH2 with high enantiopreference for (R)-4a, its crystal structure was solved by X-ray diffraction and the molecular docking of AuEH2 with (R)- or (S)-4a was simulated.

PubMed: 33316339
DOI: 10.1016/j.ijbiomac.2020.12.074

Experimental method

X-RAY DIFFRACTION (1.511 Å)