Polyketide synthases from poison hemlock (Conium maculatum L.)
Hannu Hotti1, Tuulikki Seppänen-Laakso1, Mikko Arvas1
1VTT Technical Research Centre of Finland Ltd., Espoo, Finland.
The FEBS Journal
|August 12, 2015
Summary
Researchers identified a novel enzyme, CPKS5, in poison hemlock that initiates coniine biosynthesis. This polyketide synthase (PKS) uses butyryl-CoA and malonyl-CoAs to form the toxic alkaloid
Area of Science:
- Biochemistry
- Plant Science
- Toxicology
Background:
- Coniine is a toxic alkaloid found in poison hemlock (Conium maculatum L.).
- The biosynthetic pathway of coniine is not fully understood.
- Polyketide synthases (PKS) are enzymes involved in the synthesis of various natural products.
Purpose of the Study:
- To elucidate the biosynthesis of coniine.
- To identify the specific polyketide synthase (PKS) enzymes involved in coniine production in poison hemlock.
- To characterize the function of identified PKS enzymes in vitro.
Main Methods:
- Isolation of PKS genes from poison hemlock using RACE and transcriptome analysis.
- Characterization of three full-length PKS enzymes through in vitro assays with different starter-CoAs.
- Kinetic analysis of enzyme activity.
Main Results:
- Two PKS genes (CPKS1 and CPKS2) encode chalcone synthases.
- A novel PKS, CPKS5, was identified and characterized.
- CPKS5 preferentially utilizes butyryl-CoA as a starter molecule in vitro, catalyzing the formation of the coniine backbone from butyryl-CoA and malonyl-CoAs.
Conclusions:
- CPKS5 is likely responsible for initiating coniine biosynthesis in poison hemlock.
- The study provides key insights into the enzymatic machinery underlying coniine production.
- This research contributes to understanding the biosynthesis of toxic alkaloids in plants.
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