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Structure-function studies of epoxide hydrolases

Naworyta, Agata (2010). Structure-function studies of epoxide hydrolases. Diss. (sammanfattning/summary) Uppsala : Sveriges lantbruksuniv., Acta Universitatis Agriculturae Sueciae, 1652-6880 ; 2010:5
ISBN 978-91-576-7482-1
[Doctoral thesis]

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Epoxides are three-membered cyclic ethers formed in cells via several metabolic pathways. Epoxide hydrolases (EHs) are enzymes that hydrolyse epoxides to the corresponding diols. The main goal of this thesis was to investigate the structures of EHs from the alpha/beta-hydrolase family. The first part concerns the structural and functional analysis of a protein-water channel found in EHs in many plants. Thermostability studies, sequence analysis and determination of the x-ray structure of a mutated EH enzyme from Solanum tuberosum led to the conclusions that the water channel in plants participates in stabilization of the protein structure and furthermore, it forms an efficient system to enable transfer of protons that are required for enzymatic catalysis. The second part describes how computational methods together with structural and kinetic information identified factors that are responsible for the enhanced enantioselectivity of an improved variant of EH from Aspergillus niger obtained during a directed evolution process. The x-ray structure of the mutant showed that dramatic changes in the active site explain why the preferred (S)-substrate binds more easily in the active site than the disfavored (R)-enantiomer. The study underscores the importance of obtaining structural data when attempting to understand the results of directed evolution. The last part presents the structures of two novel microbial EHs that have been shown to produce chemically valuable 1,2-diols and exhibit high enantioselectivity. Their similarity to the mammalian microsomal EH, a key enzyme in detoxification, provided new information about its possible structure. The improved sequence alignment based on the structural work gives new insights on the connections between sequences/structures and the broad scope of selectivities among EHs.

Authors/Creators:Naworyta, Agata
Title:Structure-function studies of epoxide hydrolases
Series Name/Journal:Acta Universitatis Agriculturae Sueciae
Year of publishing :2010
Number of Pages:73
ALLI. Thomaeus A., Naworyta A., Mowbray S.L., Widersten M. (2008). Removal of distal protein-water hydrogen bonds in a plant epoxide hydrolase increases catalytic turnover but decreases thermostability. Protein Science 17(7), 1275-84. II. Reetz M.T., Bocola M., Wang L.W., Sanchis J., Cronin A., Arand M., Zou J., Archelas A., Bottalla A.L., Naworyta A., Mowbray S.L. (2009). Directed evolution of an enantioselective epoxide hydrolase: uncovering the source of enantioselectivity at each evolutionary stage. J Am Chem Soc. 131(21), 7334-43. III. Naworyta A., Zhao L., Weiner D.P., Mowbray S.L. Structures of two novel microbial epoxide hydrolases showing high and broad enantioselectivity. (manuscript)
Place of Publication:Uppsala
ISBN for printed version:978-91-576-7482-1
Publication Type:Doctoral thesis
Full Text Status:Public
Agrovoc terms:epoxy compounds, hydrolases, enzymatic hydrolysis, chemical structure, crystallization, computer applications, solanum tuberosum
Keywords:chirality, crystallography, diols, enantioselectivity, enzyme, epoxide, epoxide hydrolases, regioselectivity, substrate specificity, X-ray structure
Permanent URL:
ID Code:2220
Department:(NL, NJ) > Dept. of Molecular Biology (until 131231)
Deposited By: Agata Naworyta
Deposited On:05 Feb 2010 00:00
Metadata Last Modified:02 Dec 2014 10:17

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