Involved in the production of the isoprenoid antibiotic terpentecin. Converts terpentedienol diphosphate (TDP) into terpentetriene (TTE). Can also accept geranylgeranyl diphosphate (GGDP) and farnesyl diphosphate (FDP) as substrates. terpentedienyl diphosphate = diphosphate + terpentetriene Optimum pH is 6.8. Optimum temperature is 50 degrees Celsius. Antibiotic biosynthesis. Homodimer. Mutants do not produce terpentecin. Belongs to the terpene synthase family.