4.2.3.53	(2Z,6Z)-farnesyl diphosphate	involved in sesquiterpene biosynthesis. The enzyme synthesizes a mixture of sesquiterpenoids from (2Z,6Z)-farnesyl diphosphate. Following dephosphorylation of (2Z,6Z)-farnesyl diphosphate, the (2Z,6Z)-farnesyl carbocation is converted to either the (6R)- or the (6S)-bisabolyl cations depending on the stereochemistry of the 6,1 closure. The (6R)-bisabolyl cation will then lead to the formation of (+)-alpha-santalene, while the (6S)-bisabolyl cation will give rise to (-)-endo-alpha-bergamotene and (+)-endo-beta-bergamotene. Small amounts of (-)-epi-beta-santalene are also formed from the (6R)-bisabolyl cation and small amounts of (-)-exo-alpha-bergamotene are formed from the (6S)-bisabolyl cation