Catalyzes the displacement of the beta- and gamma-phosphates of CTP by phosphonoformate to produce CMP-5'-phosphonoformate, an intermediate in the biosynthesis of phosphinothricin tripeptide (PTT). PTT is both a natural-product antibiotic and potent herbicide. CTP + phosphonoformate = CMP-5'-phosphonoformate + diphosphate Antibiotic biosynthesis; phosphinothricin biosynthesis. Deletion mutant is unable to produce PTT when grown in MYG broth supplemented with 0.5 mM phosphonoformate.