Abstract
The Pseudomonas putida esterase catalyzes the stereoselective hydrolysis of DL-ATIA to produce DAT, which is a key intermediate for synthesis of angiotensin-converting enzyme inhibitor. The crystal structure of esterase from Pseudomonas putida complex with DL-ATIA has been determined at a resolution of 2.9 Å in space group P212121, showing a characteristic α/β hydrolase fold and the DL-ATIA substrates binding information. The structure of Pseudomonas putida esterase is a timer in the asymmetry unit and there is one gorge in each monomer. The electron density shows the conserved catalytic triad active site and the entry of the binding pocket. In the Ser-His-Asp triad, the strongest stablizing interaction are three hydrogen bonds: (DL-ATIA)N-H...C=O(Ser97), 3.19Å;(His256)N-H...O=C(DL-ATIA), 3.49 Å; (His256)N-H...C=O(Asp227), 2.62 Å. The X-ray structure of PpEST reveals a narrow entry of the pocket. Several hydrophobic residues form the pocket and limit the size of the entry of the pocket, including Ile229 and Phe146. Keywords: PpEST; complex structure; catalytic triad; DL-ATIA