title: Crystal structure of the integral membrane diacylglycerol kinase.
abstract: Diacylglycerol kinase 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 crystal structures for three functional forms of this unique and paradigmatic kinase, one of which is wild type. These reveal a homo-trimeric enzyme with three transmembrane helices and an amino-terminal amphiphilic helix per monomer. Bound lipid substrate and docked ATP identify the putative active site that is of the composite, shared site type. 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.
authors.affiliation: School of Biochemistry and Immunology & School of Medicine, Trinity College Dublin, Dublin 2, Ireland.
authors.forename: Dianfan
authors.initials: D
authors.lastname: Li
authors.forename: Joseph A
authors.initials: JA
authors.lastname: Lyons
authors.forename: Valerie E
authors.initials: VE
authors.lastname: Pye
authors.forename: Lutz
authors.initials: L
authors.lastname: Vogeley
authors.forename: David
authors.initials: D
authors.lastname: Aragão
authors.forename: Colin P
authors.initials: CP
authors.lastname: Kenyon
authors.forename: Syed T A
authors.initials: ST
authors.lastname: Shah
authors.forename: Christine
authors.initials: C
authors.lastname: Doherty
authors.forename: Margaret
authors.initials: M
authors.lastname: Aherne
authors.forename: Martin
authors.initials: M
authors.lastname: Caffrey
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D020134:Catalytic Domain; D002462:Cell Membrane / Q000378:metabolism*; D018360:Crystallography, X-Ray; D019852:Diacylglycerol Kinase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D004789:Enzyme Activation / Q000187:drug effects; D004795:Enzyme Stability; D008055:Lipids; D008274:Magnesium / Q000378:metabolism; D008565:Membrane Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D008958:Models, Molecular; D050505:Mutant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D019906:Nuclear Magnetic Resonance, Biomolecular; D011487:Protein Conformation; D015032:Zinc / Q000494:pharmacology
chemical_list: D001426:Bacterial Proteins; D008055:Lipids; D008565:Membrane Proteins; D050505:Mutant Proteins; D000255:Adenosine Triphosphate; D019852:Diacylglycerol Kinase; D008274:Magnesium; D015032:Zinc