5ek8

Crystal structure of a 9R-lipoxygenase from Cyanothece PCC8801 at 2.7 Angstroms

spinqualitylabelsall models 5ek8, resolution 2.70Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 5ek8 is a 1 chain structure with sequence from Rippkaea orientalis PCC 8801. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.7Å Ligands: FE2, NA Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function B7K2Q5_RIPO1 Publication Abstract from PubMed In eukaryotes, oxidized polyunsaturated fatty acids, so-called oxylipins, are vital signaling molecules. The first step in their biosynthesis may be catalyzed by a lipoxygenase (LOX), which forms hydroperoxides by introducing dioxygen into polyunsaturated fatty acids. Here we characterized CspLOX1, a phylogenetically distant LOX family member from Cyanothece sp. PCC 8801 and determined its crystal structure. In addition to the classical two domains found in plant, animal and coral LOXs, we identified an N-terminal helical extension, reminiscent of the long alpha-helical insertion in Pseudomonas aeruginosa LOX. In liposome flotation studies, this helical extension rather than the beta-barrel domain was crucial for a membrane binding function. Additionally, CspLOX1 could oxygenate 1,2-diarachidonyl-sn-glycero-3-phosphocholine, suggesting that the enzyme may act directly on membranes and that fatty acids bind to the active site in a tail-first orientation. This binding mode is further supported by the fact that CspLOX1 catalyzed oxygenation at the n-10 position of both linoleic and arachidonic acid, resulting in 9R- and 11R-hydroperoxides, respectively. Together these results reveal unifying structural features of LOXs and their function. While the core of the active site is important for lipoxygenation and thus highly conserved, peripheral domains functioning in membrane and substrate binding are more variable. Crystal structure of a lipoxygenase from Cyanothece sp. may reveal novel features for substrate acquisition.,Newie J, Andreou A, Neumann P, Einsle O, Feussner I, Ficner R J Lipid Res. 2015 Dec 14. pii: jlr.M064980. PMID:26667668 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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