Document Detail


Molecular definitions of fatty acid hydroxylases in Arabidopsis thaliana.
MedLine Citation:
PMID:  17427946     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Towards defining the function of Arabidopsis thaliana fatty acid hydroxylases, five members of the CYP86A subfamily have been heterologously expressed in baculovirus-infected Sf9 cells and tested for their ability to bind a range of fatty acids including unsubstituted (lauric acid (C12:0) and oleic acid (C18:1)) and oxygenated (9,10-epoxystearic acid and 9,10-dihydroxystearic acid). Comparison between these five P450s at constant P450 content over a range of concentrations for individual fatty acids indicates that binding of different fatty acids to CYP86A2 always results in a higher proportion of high spin state heme than binding titrations conducted with CYP86A1 or CYP86A4. In comparison to these three, CYP86A7 and CYP86A8 produce extremely low proportions of high spin state heme even with the most effectively bound fatty acids. In addition to their previously demonstrated lauric acid hydroxylase activities, all CYP86A proteins are capable of hydroxylating oleic acid but not oxygenated 9,10-epoxystearic acid. Homology models have been built for these five enzymes that metabolize unsubstituted fatty acids and sometimes bind oxygenated fatty acids. Comparison of the substrate binding modes and predicted substrate access channels indicate that all use channel pw2a consistent with the crystal structures and models of other fatty acid-metabolizing P450s in bacteria and mammals. Among these P450s, those that bind internally oxygenated fatty acids contain polar residues in their substrate binding cavity that help stabilize these charged/polar groups within their largely hydrophobic catalytic site.
Authors:
Sangeewa G Rupasinghe; Hui Duan; Mary A Schuler
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, U.S. Gov't, Non-P.H.S.    
Journal Detail:
Title:  Proteins     Volume:  68     ISSN:  1097-0134     ISO Abbreviation:  Proteins     Publication Date:  2007 Jul 
Date Detail:
Created Date:  2007-05-28     Completed Date:  2007-12-31     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8700181     Medline TA:  Proteins     Country:  United States    
Other Details:
Languages:  eng     Pagination:  279-93     Citation Subset:  IM    
Copyright Information:
2007 Wiley-Liss, Inc.
Affiliation:
Department of Cell and Developmental Biology, University of Illinois, Urbana, Illinois 61801, USA.
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MeSH Terms
Descriptor/Qualifier:
Amino Acid Sequence
Arabidopsis / enzymology*
Arabidopsis Proteins / genetics*,  metabolism*
Chromatography, Thin Layer
Cytochrome P-450 Enzyme System / genetics*,  metabolism*
Fatty Acids / metabolism*
Mixed Function Oxygenases / genetics*,  metabolism*
Models, Molecular*
Molecular Sequence Data
Mutation / genetics
Protein Binding
Sequence Alignment
Sequence Homology
Chemical
Reg. No./Substance:
0/Arabidopsis Proteins; 0/Fatty Acids; 9035-51-2/Cytochrome P-450 Enzyme System; EC 1.-/Mixed Function Oxygenases; EC 1.14.-/CYP86A1 protein, Arabidopsis

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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