JACKSON, Miss. (AP) — Federal officials say Entergy Corp. can buy two power plants from KGen Power Corp., but say the antitrust investigation of Entergy is not over.The New Orleans utility has a deal to buy generating stations in Jackson, Miss., and Malvern, Ark., from Houston-based KGen for $459 million. But purchases of the natural-gas fired plants were frozen by a federal investigation into whether Entergy used control of transmission lines to harm independent power generators like KGen.The Justice Department said Wednesday that Entergy can complete the purchase. Officials say Entergy's plans to join a regional transmission organization called MISO and spin off long-distance power lines to ITC Holdings Corp. will end antitrust concerns. However, Justice officials say if Entergy doesn't take those steps, it may still take action against the utility.