Sesquiterpene synthase converting farnesyl diphosphate into beta-cubebene (24.5%), alpha-muurolene (19.3%), delta-cadinol (18.6%), delta-elemene (16.0%), tau-muurolene (10.8%), and beta-elemene (10.8%). No activity with geranyl diphosphate or geranylgeranyl diphosphate. (2E,6E)-farnesyl diphosphate = beta-cubebene + diphosphate Binds 3 Mg(2+) ions per subunit. kcat is 0.35 x 10(-3) sec(-1) for farnesyl diphosphate. Optimum pH is 7.5. Optimum temperature is 24-26 degrees Celsius. Secondary metabolite biosynthesis; terpenoid biosynthesis. Expressed in young developing leaves and in stamens. Not detected in tepals and carpels. The Asp-Asp-Xaa-Xaa-Asp/Glu (DDXXD/E) motif is important for the catalytic activity, presumably through binding to Mg(2+). Belongs to the terpene synthase family. Tpsa subfamily.