School of Biochemistry and Immunology & School of Medicine, Trinity College Dublin, Dublin 2, Ireland.
Nature. 2013 May 23;497(7450):521-4. doi: 10.1038/nature12179. Epub 2013 May 15.
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.
二酰基甘油激酶催化二酰基甘油的 ATP 依赖性磷酸化，生成磷脂酸，用于将水溶性成分穿梭到革兰氏阴性菌细胞包膜中衍生的寡糖和脂多糖。半个世纪以来，这种 121 个残基的激酶一直是研究膜蛋白酶学、折叠、组装和稳定性的模型。本文呈现了这种独特且典范激酶的三种功能形式的晶体结构，其中一种为野生型。这些结构揭示了一种同三聚体酶，每个单体具有三个跨膜螺旋和一个氨基末端两亲性螺旋。结合的脂类底物和结合的 ATP 确定了假定的活性位点，该活性位点属于复合共享位点类型。晶体结构合理地解释了大量关于该酶的生化和生物物理数据。然而，它们与已发表的溶液 NMR 模型存在差异，因为在晶体结构中未观察到溶液形式的关键特征——结构域交换。
