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2fnq
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(New page: 200px<br /><applet load="2fnq" size="450" color="white" frame="true" align="right" spinBox="true" caption="2fnq, resolution 3.200Å" /> '''Insights from the X...)
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Revision as of 08:31, 21 November 2007
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Insights from the X-ray crystal structure of coral 8R-lipoxygenase: calcium activation via A C2-like domain and a structural basis of product chirality
Overview
Lipoxygenases (LOXs) catalyze the regio- and stereospecific dioxygenation, of polyunsaturated membrane-embedded fatty acids. We report here the 3.2 A, resolution structure of 8R-LOX from the Caribbean sea whip coral Plexaura, homomalla, a LOX isozyme with calcium dependence and the uncommon R chiral, stereospecificity. Structural and spectroscopic analyses demonstrated, calcium binding in a C2-like membrane-binding domain, illuminating the, function of similar amino acids in calcium-activated mammalian 5-LOX, the, key enzyme in the pathway to the pro-inflammatory leukotrienes. Mutation, of Ca(2+)-ligating amino acids in 8R-LOX resulted not only in a diminished, capacity to bind membranes, as monitored by fluorescence resonance energy, transfer, but also in an associated loss of Ca(2+)-regulated enzyme, activity. Moreover, a structural basis for R chiral specificity is also, revealed; creation of a small oxygen pocket next to Gly(428) (Ala in all, S-LOX isozymes) promoted C-8 oxygenation with R chirality on the activated, fatty acid substrate.
About this Structure
2FNQ is a Single protein structure of sequence from Plexaura homomalla with FE2 and CA as ligands. This structure superseeds the now removed PDB entry 1ZQ4. Active as Arachidonate 8-lipoxygenase, with EC number 1.13.11.40 Full crystallographic information is available from OCA.
Reference
Insights from the X-ray crystal structure of coral 8R-lipoxygenase: calcium activation via a C2-like domain and a structural basis of product chirality., Oldham ML, Brash AR, Newcomer ME, J Biol Chem. 2005 Nov 25;280(47):39545-52. Epub 2005 Sep 14. PMID:16162493
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