Delta-cadinene synthase

Delta-cadinene synthase is an enzyme that plays a crucial role in the biosynthesis of sesquiterpenes, specifically the cadinene family of compounds. These sesquiterpenes are significant for their diverse biological activities and their presence in various essential oils. Delta-cadinene synthase catalyzes the conversion of farnesyl diphosphate (FPP) into delta-cadinene, a key step in the pathway leading to the synthesis of gossypol in cotton and other related terpenoids in different plants.

Function

Delta-cadinene synthase is involved in the terpenoid biosynthesis pathway, a critical process in plant metabolism that produces a wide variety of secondary metabolites. These metabolites play essential roles in plant defense mechanisms, including protection against herbivores and pathogens, and they also contribute to the plant's aroma and flavor. The enzyme specifically catalyzes the cyclization of farnesyl diphosphate (FPP) to form delta-cadinene, utilizing Mg2+ or Mn2+ as cofactors. This reaction is a key step in the pathway leading to the production of gossypol, a compound that has been extensively studied for its antifungal, antibacterial, and antiviral properties, especially in cotton plants.

Structure

Delta-cadinene synthase belongs to the terpene synthase family, enzymes known for their ability to catalyze the formation of the carbon skeletons of terpenes from simpler prenyl diphosphate substrates. The structure of delta-cadinene synthase includes several conserved motifs characteristic of the terpene synthase family, which are crucial for the enzyme's catalytic activity. These include the DDXXD motif, which is involved in the binding of the diphosphate moiety of the substrate, and the NSE/DTE motif, which is important for the binding of the divalent metal ion cofactors.

Genetic Expression

The expression of the delta-cadinene synthase gene is highly regulated and can be induced by various environmental factors, including pathogen attack, physical wounding, and chemical treatments. This regulation ensures that plants can rapidly produce terpenoid compounds in response to stress, providing a timely defense mechanism. In cotton, the gene encoding delta-cadinene synthase is specifically expressed in the roots, stems, and leaves, with the highest expression levels observed in the tissues that are most vulnerable to pathogen attack.

Applications

The study of delta-cadinene synthase and its role in terpenoid biosynthesis has significant implications for agriculture and medicine. By understanding the mechanisms underlying the production of gossypol and other terpenoids, researchers can develop strategies to enhance plant resistance to pests and diseases. Additionally, the terpenoids synthesized by delta-cadinene synthase and related enzymes have potential applications in the pharmaceutical industry due to their bioactive properties.

See Also

• Terpenoid
• Sesquiterpene
• Farnesyl diphosphate
• Gossypol
• Terpene synthase

References

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