5IR5 image
Entry Detail
PDB ID:
5IR5
Keywords:
Title:
Crystal structure of wild-type bacterial lipoxygenase from Pseudomonas aeruginosa PA-LOX with space group P21212 at 1.9 A resolution
Biological Source:
Source Organism:
Host Organism:
PDB Version:
Deposition Date:
2016-03-12
Release Date:
2016-08-10
Method Details:
Experimental Method:
Resolution:
1.90 Å
R-Value Free:
0.18
R-Value Work:
0.14
R-Value Observed:
0.14
Space Group:
P 21 21 2
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:Arachidonate 15-lipoxygenase
Chain IDs:A
Chain Length:688
Number of Molecules:1
Biological Source:Pseudomonas aeruginosa
Primary Citation
Structural and functional basis of phospholipid oxygenase activity of bacterial lipoxygenase from Pseudomonas aeruginosa.
Biochim.Biophys.Acta 1861 1681 1692 (2016)
PMID: 27500637 DOI: 10.1016/j.bbalip.2016.08.002

Abstact

Pseudomonas aeruginosa expresses a secreted LOX-isoform (PA-LOX, LoxA) capable of oxidizing polyenoic fatty acids to hydroperoxy derivatives. Here we report high-level expression of this enzyme in E. coli and its structural and functional characterization. Recombinant PA-LOX oxygenates polyenoic fatty acids including eicosapentaenoic acid and docosahexaenoic acid to the corresponding (n-6)S-hydroperoxy derivatives. This reaction involves abstraction of the proS-hydrogen from the n-8 bisallylic methylene. PA-LOX lacks major leukotriene synthase activity but converts 5S-HETE and 5S,6R/S-DiHETE to anti-inflammatory and pro-resolving lipoxins. It also exhibits phospholipid oxygenase activity as indicated by the formation of a specific pattern of oxygenation products from different phospholipid subspecies. Multiple mutagenesis studies revealed that PA-LOX does not follow classical concepts explaining the reaction specificity of mammalian LOXs. The crystal structure of PA-LOX was solved with resolutions of up to 1.48Å and its polypeptide chain is folded as single domain. The substrate-binding pocket consists of two fatty acid binding subcavities and lobby. Subcavity-1 contains the catalytic non-heme iron. A phosphatidylethanolamine molecule occupies the substrate-binding pocket and its sn1 fatty acid is located close to the catalytic non-heme iron. His377, His382, His555, Asn559 and the C-terminal Ile685 function as direct iron ligands and a water molecule (hydroxyl) completes the octahedral ligand sphere. Although the biological relevance of PA-LOX is still unknown its functional characteristics (lipoxin synthase activity) implicate this enzyme in a bacterial evasion strategy aimed at downregulating the hosts' immune system.

Legend

Protein

Chemical

Disease

Primary Citation of related structures