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Allene oxide synthases and allene oxides
1Department of Pharmacology, Vanderbilt University Medical School, Nashville, TN 37232-6602, USA.
Prostaglandins & Other Lipid Mediators
|November 16, 2002
Summary
Allene oxide synthases, crucial for plant signaling molecules and coral eicosanoids, exist in two distinct types: plant cytochromes P450 (CYP74A) and coral catalase-related hemoproteins.
Area of Science:
- Biochemistry
- Enzymology
- Marine Biology
Background:
- Allene oxides are reactive epoxides derived from polyunsaturated fatty acids.
- Enzymatic pathways generate allene oxides, which serve as precursors to signaling molecules.
- Two structurally distinct enzyme families catalyze allene oxide formation.
Purpose of the Study:
- To investigate the diversity and function of allene oxide synthases.
- To elucidate the roles of these enzymes in plant and marine invertebrate systems.
- To explore the biosynthesis of signaling molecules and eicosanoids.
Main Methods:
- Comparative analysis of enzyme structures and functions.
- Substrate specificity studies using fatty acid hydroperoxides.
- Identification and characterization of allene oxide synthase enzymes in plants and corals.
Main Results:
- Plant allene oxide synthases belong to the cytochrome P450 subfamily CYP74A, processing linoleic and linolenic acid hydroperoxides.
- Marine invertebrates like corals utilize catalase-related hemoproteins for allene oxide synthesis from arachidonic acid.
- Coral allene oxide synthase from Plexaura homomalla is a fusion protein with 8R-lipoxygenase, potentially involved in clavulone biosynthesis.
Conclusions:
- Allene oxide synthases exhibit significant structural and functional divergence between plants and marine organisms.
- These enzymes play critical roles in producing distinct classes of bioactive molecules, including plant signaling compounds and coral eicosanoids.
- The discovery of fusion proteins highlights novel enzymatic architectures in marine invertebrates.