In vitro phosphorylates phosphatidylglycerol but not diacylglycerol; the in vivo substrate is unknown. Binds 1 Mg(2+) ion per subunit. Ca(2+) may be able to substitute. Optimum pH is 7.5. Active from pH 5 to 9. Monomer. Belongs to the diacylglycerol/lipid kinase family. YegS lipid kinase subfamily.