4NZZ: Crystal Structure Of Epoxide Hydrolase From Bacillus Megaterium

Citation:
Abstract
Optically pure epoxides are essential chiral precursors for the production of (S)-propranolol, (S)-alprenolol, and other beta-adrenergic receptor blocking drugs. Although the enzymatic production of these bulky epoxides has proven difficult, here we report a method to effectively improve the activity of BmEH, an epoxide hydrolase from Bacillus megaterium ECU1001 toward alpha-naphthyl glycidyl ether, the precursor of (S)-propranolol, by eliminating the steric hindrance near the potential product-release site. Using X-ray crystallography, mass spectrum, and molecular dynamics calculations, we have identified an active tunnel for substrate access and product release of this enzyme. The crystal structures revealed that there is an independent product-release site in BmEH that was not included in other reported epoxide hydrolase structures. By alanine scanning, two mutants, F128A and M145A, targeted to expand the potential product-release site displayed 42 and 25 times higher activities toward alpha-naphthyl glycidyl ether than the wild-type enzyme, respectively. These results show great promise for structure-based rational design in improving the catalytic efficiency of industrial enzymes for bulky substrates.
PDB ID: 4NZZDownload
MMDB ID: 124312
PDB Deposition Date: 2013/12/13
Updated in MMDB: 2014/11
Experimental Method:
x-ray diffraction
Resolution: 1.75  Å
Source Organism:
Similar Structures:
Biological Unit for 4NZZ: monomeric; determined by author and by software (PISA)
Molecular Components in 4NZZ
Label Count Molecule
Protein (1 molecule)
1
Soluble Epoxide Hydrolase
Molecule annotation
* Click molecule labels to explore molecular sequence information.

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