4Y9S

structure of an H300N mutant of potato epoxide hydrolase, StEH1


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2 Å
  • R-Value Free: 0.199 
  • R-Value Work: 0.147 

wwPDB Validation 3D Report Full Report


This is version 1.1 of the entry. See complete history

Literature

Expanding the Catalytic Triad in Epoxide Hydrolases and Related Enzymes.

Amrein, B.A.Bauer, P.Duarte, F.Janfalk Carlsson, A.Naworyta, A.Mowbray, S.L.Widersten, M.Kamerlin, S.C.

(2015) ACS Catal 5: 5702-5713

  • DOI: 10.1021/acscatal.5b01639

  • PubMed Abstract: 
  • Potato epoxide hydrolase 1 exhibits rich enantio- and regioselectivity in the hydrolysis of a broad range of substrates. The enzyme can be engineered to increase the yield of optically pure products as a result of changes in both enantio- and regiose ...

    Potato epoxide hydrolase 1 exhibits rich enantio- and regioselectivity in the hydrolysis of a broad range of substrates. The enzyme can be engineered to increase the yield of optically pure products as a result of changes in both enantio- and regioselectivity. It is thus highly attractive in biocatalysis, particularly for the generation of enantiopure fine chemicals and pharmaceuticals. The present work aims to establish the principles underlying the activity and selectivity of the enzyme through a combined computational, structural, and kinetic study using the substrate trans-stilbene oxide as a model system. Extensive empirical valence bond simulations have been performed on the wild-type enzyme together with several experimentally characterized mutants. We are able to computationally reproduce the differences between the activities of different stereoisomers of the substrate and the effects of mutations of several active-site residues. In addition, our results indicate the involvement of a previously neglected residue, H104, which is electrostatically linked to the general base H300. We find that this residue, which is highly conserved in epoxide hydrolases and related hydrolytic enzymes, needs to be in its protonated form in order to provide charge balance in an otherwise negatively charged active site. Our data show that unless the active-site charge balance is correctly treated in simulations, it is not possible to generate a physically meaningful model for the enzyme that can accurately reproduce activity and selectivity trends. We also expand our understanding of other catalytic residues, demonstrating in particular the role of a noncanonical residue, E35, as a "backup base" in the absence of H300. Our results provide a detailed view of the main factors driving catalysis and regioselectivity in this enzyme and identify targets for subsequent enzyme design efforts.


    Organizational Affiliation

    Science for Life Laboratory, Department of Cell and Molecular Biology, Uppsala University , BMC Box 596, SE-751 24 Uppsala, Sweden.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Epoxide hydrolase
A, B
328Solanum tuberosumMutation(s): 1 
Find proteins for Q41415 (Solanum tuberosum)
Go to UniProtKB:  Q41415
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2 Å
  • R-Value Free: 0.199 
  • R-Value Work: 0.147 
  • Space Group: P 21 21 21
Unit Cell:
Length (Å)Angle (°)
a = 56.021α = 90.00
b = 96.036β = 90.00
c = 121.551γ = 90.00
Software Package:
Software NamePurpose
SCALAdata scaling
MOSFLMdata reduction
REFMACphasing
REFMACrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
VetenskapsradetSweden--

Revision History 

  • Version 1.0: 2015-09-16
    Type: Initial release
  • Version 1.1: 2017-07-19
    Type: Database references