Prenyltransferase that catalyzes the transfer of the geranylgeranyl moiety of geranylgeranyl diphosphate (GGPP) to the C3 hydroxyl of sn-glycerol-1-phosphate (G1P). This reaction is the first ether-bond-formation step in the biosynthesis of archaeal membrane lipids. Cannot use sn-glycerol-3-phosphate (G3P) or dihydroxyacetonephosphate (DHAP) as substrate. (2E,6E,10E)-geranylgeranyl diphosphate + sn-glycerol 1-phosphate = diphosphate + sn-3-O-(geranylgeranyl)glycerol 1-phosphate Inhibited by EDTA in vitro. Optimum pH is 6.0-9.0. Optimum temperature is 55 degrees Celsius at pH 8.0. Membrane lipid metabolism; glycerophospholipid metabolism. Homopentamer. Belongs to the GGGP/HepGP synthase family. Group II subfamily.