GO:0008444:   CDP-diacylglycerol-glycerol-3-phosphate 3-phosphatidyltransferase activity
Catalysis of the reaction: sn-glycerol 3-phosphate + CDP-diacylglycerol = 3-(3-sn-phosphatidyl)-sn-glycerol 1-phosphate + CMP + H(+).