Acyl-coenzyme A thioesterase 7 (ACOT7) plays a crucial role in the metabolism of activated fatty acids, including the production of many inflammatory molecules. We have crystallised and determined the structure of ACOT7, a hexameric hot-dog domain-containing acyl-CoA thioesterase, through a combination of chemical crosslinking, x-ray crystallography, mass spectrometry, and molecular modelling. An exciting corollary of our recent functional work is that the enzyme is highly expressed in macrophages and upregulated by pro-inflammatory stimuli, overexpression in macrophages increases prostaglandin production, the active sites exhibit a half of sites binding, and the activity  in vitro can be inhibited by small molecular metabolites. We have also recently determined the structure of bacterial homologues, both in the apo and bound forms, and identified key conformational changes induced upon ligand binding. Ligand-induced changes occur at both the hot-dog dimer and trimer-of-dimer interfaces; the dimer interfaces in the apo-structure differ by over 20% from one another, and decrease to about half the size in the ligand-bound state. The conformational changes are likely to be conserved from bacteria through to humans, and provide a greater understanding, particularly at a structural level, of thioesterases and their role in inflammation.