Terpene cyclase that catalyzes the cyclization of farnesyl diphosphate (FPP) to various sesquiterpenes, including alpha-cubebene, beta-cubebene, sativene, cyclosativene, sesquisabinene, alpha-copaene, beta-copaene, cadina-1(6),4-diene, alpha-muurolene, gamma-muurolene, bicyclosesquiphellandrene, allo-aromadendr-9-en, epi-cubebol, cubebol and delta-cadinene. (2E,6E)-farnesyl diphosphate = alpha-copaene + diphosphate (2E,6E)-farnesyl diphosphate = beta-copaene + diphosphate (2E,6E)-farnesyl diphosphate = delta-cadinene + diphosphate (2E,6E)-farnesyl diphosphate = beta-cubebene + diphosphate (2E,6E)-farnesyl diphosphate = alpha-muurolene + diphosphate (2E,6E)-farnesyl diphosphate = diphosphate + gamma-muurolene The conserved DDXXD and NSE/DTE motifs are important for the catalytic activity, presumably through binding to Mg(2+). Belongs to the terpene synthase family.