Prenyltransferase that catalyzes the transfer of the geranylgeranyl moiety of geranylgeranyl diphosphate (GGPP) to the C2 hydroxyl of (S)-3-O-geranylgeranylglyceryl phosphate (GGGP). This reaction is the second ether-bond-formation step in the biosynthesis of archaeal membrane lipids. Cannot use other prenyl donors, i.e. farnesyl diphosphate (FPP) and phytyl diphosphate. Moreover, 4-hydroxybenzoate, 1,4-dihydroxy 2-naphthoate, homogentisate, and alpha-glycerophosphate do not function as prenyl acceptor substrates. (2E,6E,10E)-geranylgeranyl diphosphate + sn-3-O-(geranylgeranyl)glycerol 1-phosphate = 2,3-bis-O-(geranylgeranyl)-sn-glycerol 1-phosphate + diphosphate Magnesium. Can also use Ca(2+), but less efficiently. Inhibited by EDTA in vitro. Optimum pH is 6.0. Membrane lipid metabolism; glycerophospholipid metabolism. Belongs to the UbiA prenyltransferase family. DGGGP synthase subfamily.