Cryo-EM structures of human arachidonate 12S-Lipoxygenase (12-LOX) bound to endogenous and exogenous inhibitors

Mobbs, JI; Black, KA; Tran, M; Burger, WAC; Venugopal, H; Holman, TR; Holinstat, M; Thal, D; Glukhova, A

Author(s): Mobbs, JI; Black, KA; Tran, M; Burger, WAC; Venugopal, H; Holman, TR; Holinstat, M; Thal, D; Glukhova, A;
Details: Publication Year 2023-07-28,Volume 142,Issue #14,Page 1233-1242
Journal Title: Blood
Abstract: Human 12-lipoxygenase (12-LOX) is a key enzyme involved in platelet activation and regulation of its activity has been targeted for treatment of heparin-induced thrombocytopenia. Despite the clinical importance of 12-LOX, the exact mechanisms of how 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 the high-resolution structures (1.7 Å - 2.8 Å) of human 12-LOX for the first time. Our results showed that 12-LOX can exist in multiple oligomeric states, from monomer to hexamer, which may impact its catalytic activity and membrane association. We also identified different conformations within a 12-LOX dimer, likely representing different time points in its catalytic cycle. Furthermore, we were able to identify small molecules bound to the 12-LOX structures. The active site of the 12-LOX tetramer is occupied by an endogenous 12-LOX inhibitor, a long-chain acyl-Coenzyme A. Additionally, 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 I clinical trial for treating heparin-induced thrombocytopenia and has received fast-track designation by the FDA. Overall, our findings provide novel insights into the assembly of 12-LOX oligomers, its catalytic mechanism, and small molecule binding, paving the way for further drug development targeting the 12-LOX enzyme.
Publisher: ASH
Keywords: United States; Humans; Cryoelectron Microscopy; *Platelet Activation; Arachidonic Acid/metabolism; Arachidonate 12-Lipoxygenase/metabolism; *Thrombocytopenia
Research Division(s): Structural Biology
PubMed ID: 37506345
Publisher's Version: https://doi.org/10.1182/blood.2023020441
Terms of Use/Rights Notice: Refer to copyright notice on published article.

Creation Date: 2023-09-21 11:41:16

Last Modified: 2023-12-13 10:19:48