InterPro domain: IPR005630

Sequences containing this domain belong to the terpene synthase family [ 1 ]. It has been suggested that this gene family be designated tps (for terpene synthase). Sequence comparisons reveal similarities between the monoterpene (C ₁₀ ) synthases, sesquiterpene (C ₁₅ ) synthases and the diterpene (C ₂₀ ) synthases. It has been split into six subgroups on the basis of phylogeny, called Tpsa-Tpsf [ 2 ].

• Tpsa includes vetispiradiene synthase Q39979 , 5-epi- aristolochene synthase, Q40577 and (+)-delta-cadinene synthase P93665 .
• Tpsb includes (-)-limonene synthase, Q40322 .
• Tpsc includes copalyl diphosphate synthase (kaurene synthase A), O04408 .
• Tpsd includes taxadiene synthase, Q41594 , pinene synthase, O24475 and myrcene synthase, O24474 .
• Tpse includes ent-kaurene synthase B Q39548 .
• Tpsf includes linalool synthase Q9ZPN5 .

In the fungus Phaeosphaeria sp. (strain L487) the synthesis of ent-kaurene from geranylgeranyl diphosphate is promoted by a single bifunctional protein [ 3 ].

This domain is involved in the cyclization of linear terpenes [ 4 , 4 , 5 , 6 , 7 , 8 ].

1. Structural and Chemical Biology of Terpenoid Cyclases. Chem Rev 117, 11570-11648
2. Monoterpene synthases from grand fir (Abies grandis). cDNA isolation, characterization, and functional expression of myrcene synthase, (-)-(4S)-limonene synthase, and (-)-(1S,5S)-pinene synthase. J. Biol. Chem. 272, 21784-92
3. Ent-kaurene synthase from the fungus Phaeosphaeria sp. L487. cDNA isolation, characterization, and bacterial expression of a bifunctional diterpene cyclase in fungal gibberellin biosynthesis. J. Biol. Chem. 272, 21706-12
4. Crystal structure of pentalenene synthase: mechanistic insights on terpenoid cyclization reactions in biology. Science 277, 1820-4
5. Bornyl diphosphate synthase: structure and strategy for carbocation manipulation by a terpenoid cyclase. Proc. Natl. Acad. Sci. U.S.A. 99, 15375-80
6. X-ray crystal structure of aristolochene synthase from Aspergillus terreus and evolution of templates for the cyclization of farnesyl diphosphate. Biochemistry 46, 1941-51
7. Structure of epi-isozizaene synthase from Streptomyces coelicolor A3(2), a platform for new terpenoid cyclization templates. Biochemistry 49, 1787-97
8. Structure of isoprene synthase illuminates the chemical mechanism of teragram atmospheric carbon emission. J. Mol. Biol. 402, 363-73