5EK8

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

Summary for 5EK8

• Entry DOI: 10.2210/pdb5ek8/pdb
• Descriptor: Lipoxygenase, FE (II) ION, SODIUM ION, ... (4 entities in total)
• Functional Keywords: non-heme iron, plat domain, lipoxygenase, oxidoreductase
• Biological source: Cyanothece sp. (strain PCC 8801)
• Total number of polymer chains: 1
• Total formula weight: 76683.84

Authors

Feussner, I.,Ficner, R.,Neumann, P.,Newie, J.,Andreou, A.,Einsle, O. (deposition date: 2015-11-03, release date: 2015-12-23, Last modification date: 2024-05-08)

Primary citation

Newie, J.,Andreou, A.,Neumann, P.,Einsle, O.,Feussner, I.,Ficner, R.
Crystal structure of a lipoxygenase from Cyanothece sp. may reveal novel features for substrate acquisition.
J.Lipid Res., 57:276-287, 2016

PubMed Abstract: In eukaryotes, oxidized PUFAs, 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 PUFAs. 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 α-helical insertion in Pseudomonas aeruginosa LOX. In liposome flotation studies, this helical extension, rather than the β-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.

PubMed: 26667668
DOI: 10.1194/jlr.M064980

Experimental method

X-RAY DIFFRACTION (2.7 Å)