Diacylglycerol kinase (DgkA) catalyses the ATP-dependent phosphorylation of diacylglycerol to phosphatidic acid for use in shuttling water-soluble components to membrane-derived oligosaccharide and lipopolysaccharide in the cell envelope of Gram-negative bacteria. For half a century, this 121 residue kinase has served as a model for investigating membrane protein enzymology, folding, assembly and stability. Here we present a case study where the use of non-standard lipids for the in meso crystallization methodology 1-4 successfully yielded the tridimensional structure of DgkA5 . Considerations are made on data collections strategies and difficulties during structure determination. The crystal structures rationalize extensive biochemical and biophysical data on the enzyme. They are,however, at variance with a published solution NMR model in that domain swapping, a key feature of the solution form, is not observed in the crystal structures.