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A Customizable Approach for the Enzymatic Production and Purification of Diterpenoid Natural Products
Published on: October 4, 2019
Defining the potassium binding region in an apple terpene synthase
Sol Green1, Christopher J Squire, Niels J Nieuwenhuizen
1The New Zealand Institute for Plant and Food Research, Mt. Albert, Private Bag 92169, Auckland, New Zeland. sol.green@hortresearch.co.nz
The Journal of Biological Chemistry
|February 3, 2009
Summary
Monovalent cations like potassium (K+) are essential for some terpene synthase enzymes. Researchers identified a specific H-alphal loop region crucial for K+ binding and catalysis in these enzymes.
Area of Science:
- Biochemistry
- Enzymology
- Organic Chemistry
Background:
- Terpene synthases produce diverse natural terpenoids.
- Enzyme activity often requires divalent metal ions (M2+) and sometimes monovalent cations (M+).
- Potassium ions (K+) are known activators for certain terpene synthases.
Purpose of the Study:
- To identify active site regions involved in monovalent cation (M+) binding.
- To investigate the role of potassium (K+) in apple alpha-farnesene synthase (MdAFS1) activity.
- To confirm the function of a specific protein loop in M+ coordination.
Main Methods:
- Protein homology modeling of apple alpha-farnesene synthase (MdAFS1).
- Site-directed mutagenesis of specific residues within the H-alphal loop.
- Comparative analysis using a conifer pinene synthase.
Main Results:
- A surface-exposed loop (H-alphal loop) was identified as a potential K+ binding site in MdAFS1.
- Mutagenesis confirmed the critical role of H-alphal loop residues in K+ response and binding.
- Similar findings were observed in a conifer pinene synthase, indicating conserved function.
Conclusions:
- Direct evidence for a specific M+ binding region (H-alphal loop) in terpene synthases.
- Establishes a basis for understanding K+ activation mechanisms in terpene synthases.
- Identifies a novel role for the H-alphal loop in enzyme catalysis.
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