Amorpha-4,11-diene Synthase

Amorpha-4,11-diene synthase (ADS) is an enzyme that catalyzes the conversion of farnesyl pyrophosphate (FPP) to amorpha-4,11-diene (AD), a key intermediate in the biosynthesis of the antimalarial drug artemisinin. This enzyme is a member of the terpene synthase family, which is responsible for the production of a wide variety of terpenoid compounds.

Function

Amorpha-4,11-diene synthase is a sesquiterpene synthase that catalyzes the cyclization of FPP to AD. This reaction involves a series of complex molecular rearrangements, including a 1,6-ring closure followed by a 1,2-hydride shift and a 1,10-ring closure. The product, AD, is then further modified by other enzymes to produce artemisinin.

Structure

The structure of ADS has been determined by X-ray crystallography. The enzyme is a monomer and consists of two domains: a large alpha-helical domain and a smaller beta-sheet domain. The active site, where the reaction takes place, is located in a large cavity at the interface of the two domains.

Role in Artemisinin Biosynthesis

Artemisinin is a potent antimalarial drug derived from the plant Artemisia annua. The biosynthesis of artemisinin involves several steps, starting with the conversion of FPP to AD by ADS. This is followed by a series of modifications by other enzymes, including cytochrome P450 enzymes and a peroxidase, to produce the final product.

See Also

• Artemisinin
• Farnesyl pyrophosphate
• Terpene synthase
• Sesquiterpene synthase