FIGURE 6.

Alignment of chrysanthemol synthase with two other bifunctional short-chain terpene synthases and FDS, the ancestor of CHS. AaFDS, FDS from sagebrush (Artemisia annua), which is also in the Asteraceae family as pyrethrum (T. cinerariifolium); TcCHS, bifunctional chryanthemyl diphosphate/chrysanthemol synthase from pyrethrum; IpMS, bifunctional geranyl diphosphate/myrcene synthase from bark beetle (I. pini); MdFS, bifunctional FDS/farnesene synthase from apple (M. domestica). The boxes indicate the conserved DDXXD domain of prenyltransferases and terpene synthases. SQS and PTS have very limited similarity to short-chain prenyltransferases or terpene synthases, with only the motif GXXXQXXDDXXD at the second DDXXD region in FDS partially conserved (DD = Ni) (8).