1u5u
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(New page: 200px<br /><applet load="1u5u" size="450" color="white" frame="true" align="right" spinBox="true" caption="1u5u, resolution 2.00Å" /> '''The structure of an ...)
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Revision as of 01:44, 21 November 2007
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The structure of an Allene Oxide Synthase reveals a novel use for a catalase fold
Overview
8R-Lipoxygenase and allene oxide synthase (AOS) are parts of a naturally, occurring fusion protein from the coral Plexaura homomalla. AOS catalyses, the production of an unstable epoxide (an allene oxide) from the fatty, acid hydroperoxide generated by the lipoxygenase activity. Here, we report, the structure of the AOS domain and its striking structural homology to, catalase. Whereas nominal sequence identity between the enzymes had been, previously described, the extent of structural homology observed was not, anticipated, given that this enzyme activity had been exclusively, associated with the P450 superfamily, and conservation of a catalase fold, without catalase activity is unprecedented. Whereas the heme environment, is largely conserved, the AOS heme is planar and the distal histidine is, flanked by two hydrogen-bonding residues. These critical differences, likely facilitate the switch from a catalatic activity to that of a fatty, acid hydroperoxidase.
About this Structure
1U5U is a Single protein structure of sequence from Plexaura homomalla with HEM as ligand. Active as Hydroperoxide dehydratase, with EC number 4.2.1.92 Full crystallographic information is available from OCA.
Reference
The structure of coral allene oxide synthase reveals a catalase adapted for metabolism of a fatty acid hydroperoxide., Oldham ML, Brash AR, Newcomer ME, Proc Natl Acad Sci U S A. 2005 Jan 11;102(2):297-302. Epub 2004 Dec 29. PMID:15625113
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