Curcuminoid biosynthesis by two type III polyketide synthases in the herb Curcuma longa

Area of Science:

• Biochemistry
• Plant Science
• Natural Product Synthesis

Background:

• Curcuminoids, found in turmeric (Curcuma longa), exhibit significant biological activities and complex structures.
• Despite their importance, the enzymatic pathways for curcuminoid biosynthesis remain largely unelucidated.
• Understanding this pathway is crucial for harnessing the pharmaceutical potential of curcuminoids.

Purpose of the Study:

• To elucidate the biosynthetic pathway of curcuminoids in Curcuma longa.
• To identify and characterize the novel enzymes involved in curcuminoid synthesis.
• To provide a molecular basis for the production of curcuminoids.

Main Methods:

• Identification and characterization of two novel type III polyketide synthases (PKS).
• In vitro enzymatic assays using feruloyl-CoA, malonyl-CoA, and synthetic substrates.
• Co-incubation experiments to assess the synergistic activity of the identified enzymes.

Main Results:

• Diketide-CoA synthase (DCS) was identified, catalyzing the formation of feruloyldiketide-CoA from feruloyl-CoA and malonyl-CoA.
• Curcumin synthase (CURS) was identified, converting diketide-CoA esters into curcuminoid scaffolds.
• Co-expression of DCS and CURS efficiently produced curcumin, highlighting their collaborative role in the pathway.

Conclusions:

• The study reveals a novel pathway for curcuminoid biosynthesis in turmeric involving DCS and CURS.
• These enzymes represent key players in the formation of the curcuminoid scaffold.
• This elucidation provides a foundation for future metabolic engineering and drug development efforts.