8GHC

The structure of h12-LOX in dimeric form

Summary for 8GHC

• Entry DOI: 10.2210/pdb8ghc/pdb
• EMDB information: 40040 40299 40300 40301
• Descriptor: Polyunsaturated fatty acid lipoxygenase ALOX12, FE (II) ION (2 entities in total)
• Functional Keywords: lipoxygenase, platelets, lipid-modifying enzyme, lipid oxidation, oxidoreductase
• Biological source: Homo sapiens (human)
• Total number of polymer chains: 2
• Total formula weight: 153277.10

Authors

Black, K.A.,Mobbs, J.I.,Venugopal, H.,Thal, D.M.,Glukhova, A. (deposition date: 2023-03-09, release date: 2023-08-09, Last modification date: 2023-10-11)

Primary citation

Mobbs, J.I.,Black, K.A.,Tran, M.,Burger, W.A.C.,Venugopal, H.,Holman, T.R.,Holinstat, M.,Thal, D.M.,Glukhova, A.
Cryo-EM structures of human arachidonate 12S-lipoxygenase bound to endogenous and exogenous inhibitors.
Blood, 142:1233-1242, 2023

PubMed Abstract: Human 12-lipoxygenase (12-LOX) is a key enzyme involved in platelet activation, and the regulation of its activity has been targeted for the treatment of heparin-induced thrombocytopenia. Despite the clinical importance of 12-LOX, the exact mechanisms by which it affects platelet activation are not fully understood, and the lack of structural information has limited drug discovery efforts. In this study, we used single-particle cryo-electron microscopy to determine high-resolution structures (1.7-2.8 Å) of human 12-LOX. Our results showed that 12-LOX can exist in multiple oligomeric states, from monomer to hexamer, which may affect its catalytic activity and membrane association. We also identified different conformations within the 12-LOX dimer, which likely represent different time points in its catalytic cycle. Furthermore, we identified small molecules bound to 12-LOX. The active site of the 12-LOX tetramer was occupied by an endogenous 12-LOX inhibitor, a long-chain acyl coenzyme A. In addition, we found that the 12-LOX hexamer can simultaneously bind to arachidonic acid and ML355, a selective 12-LOX inhibitor that has passed a phase 1 clinical trial for the treatment of heparin-induced thrombocytopenia and received a fast-track designation by the Food and Drug Administration. Overall, our findings provide novel insights into the assembly of 12-LOX oligomers, their catalytic mechanism, and small molecule binding, paving the way for further drug development targeting the 12-LOX enzyme.

PubMed: 37506345
DOI: 10.1182/blood.2023020441

Experimental method

ELECTRON MICROSCOPY (2.3 Å)