Catalyzes the ATP-dependent phosphorylation of sn-l,2-diacylglycerol (DAG) to phosphatidic acid (PubMed:218816, PubMed:6277376, PubMed:6303781, PubMed:2984194, PubMed:3009449, PubMed:2828054, PubMed:9305868). Involved in the recycling of diacylglycerol produced as a by-product during membrane-derived oligosaccharide (MDO) biosynthesis (PubMed:217867, PubMed:6305970). In vitro, phosphorylates various substrates, including sn-1,2-dioleoylglycerol, sn-1,2-dioctanoylglycerol, sn-1,2-dipalmitoylglycerol, sn-1,2-dipalmitate and ceramide (PubMed:218816, PubMed:2984194, PubMed:3009449, PubMed:3021764, PubMed:2828054). Catalyzes direct phosphoryl transfer from Mg-ATP to diacylglycerol and does not form an enzyme-phosphate intermediate (PubMed:9305868). a 1,2-diacyl-sn-glycerol + ATP = a 1,2-diacyl-sn-glycero-3-phosphate + ADP + H(+) 1,2-di-(9Z-octadecenoyl)-sn-glycerol + ATP = 1,2-di-(9Z-octadecenoyl)-sn-glycero-3-phosphate + ADP + H(+) Mn(2+), Zn(2+), Cd(2+) and Co(2+) support activity to lesser extents. Requires a lipid activator for activity. Activation is observed with cardiolipin and a large number of phospholipids, sulfolipids, neutral lipids, fatty acids, alkylglycosides or detergents (PubMed:6277376, PubMed:6303781, PubMed:2984194, PubMed:3009449, PubMed:3021764, PubMed:2828054). A lipid cofactor-induced conformational change may occur as part of the activation process (PubMed:3021764). Requires a second divalent cation in addition to Mg(2+)-ATP (PubMed:3009449). Inhibited by the tetraphosphate-linked ATP-DAG bisubstrate analog (PubMed:9305868). Optimum pH is 6.3-8.3. Apoprotein in organic solution has an unusual stability towards heating to 100 degrees Celsius. Homotrimer. Expression is activated by the two-component system BasRS. Repressed by sigma-E factor. Contains three transmembrane helices and a N-terminal amphiphilic helix located on the cytoplasmic surface (PubMed:23676677, PubMed:26673816). Residues from different subunits participate in forming the active site (PubMed:10220339, PubMed:23676677). Contains three catalytic and substrate-binding sites centred about the membrane/cytosol interface (PubMed:26673816). The gamma-phosphate of the ATP is positioned for direct transfer to the primary hydroxyl of the lipid whose acyl chain is in the membrane (PubMed:26673816). The presence of Trp residues has a clear effect on thermal stability. Of the mutants containing a single Trp residue, only that containing Trp-113 was found to give active protein. Mutant lacking this gene accumulates substantial amounts of diglyceride in the cytoplasmic membrane (PubMed:206553, PubMed:217867). Mutant also accumulates monoglyceride and triglyceride. Monoglyceride accumulates predominantly in the outer membrane, while triglyceride builds up together with diglyceride in the cytoplasmic membrane (PubMed:6305970). This small kinase has long served as a model for investigating membrane protein enzymology, folding, assembly and stability. Belongs to the bacterial diacylglycerol kinase family.