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The crystal structure of human 15‐lipoxygenase‐2 in complex with a substrate mimic
Author(s) -
Kobe Matthew James,
Bartlett Sue G,
Newcomer Marcia
Publication year - 2013
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.27.1_supplement.561.10
Subject(s) - enzyme , chemistry , förster resonance energy transfer , lipoxygenase , active site , substrate (aquarium) , biochemistry , lipid signaling , arachidonate 5 lipoxygenase , gene isoform , biophysics , stereochemistry , biology , arachidonic acid , fluorescence , ecology , physics , quantum mechanics , gene
Lipoxygenases (LOX) are a family of enzymes that produce, among other lipid mediators, eicosanoids capable of provoking and suppressing the inflammatory response. Atherosclerosis is associated with unchecked inflammation occurring over decades in humans. 15‐Lipoxygenase‐2 (15‐LOX‐2) is highly expressed in large, human atherosclerotic plaques. In order to gain insight into the catalytic activity of 15‐LOX‐2 and any role the enzyme or its products may play in plaque formation, we solved the crystal structure to 2.65 Å resolution. The structure revealed a detergent molecule bound in the active site that appears to bind as a substrate mimic. Kinetic experiments confirm that the detergent C8E4 competitively inhibits the enzyme. Unlike other LOX, the 15‐LOX‐2 structure has a long loop composed of nonpolar amino acids emanating from the polycystin‐1, lipoxygenase, alpha‐toxin (PLAT) domain. The PLAT domain loop is flanked by what appear to be two calcium‐binding sites, also found in human 5‐LOX. Förster resonance energy transfer (FRET) experiments indicate that Ca2+ induces membrane binding of 15‐LOX‐2 to Dansyl‐labeled liposomes. A comparison of human 15‐LOX‐2 and human 5‐LOX indicates significant differences in active site structures that can be exploited for isoform selective inhibitor design. The work was funded by a grant from the National Heart, Lung, and Blood Institute R01 (107887.)