ARS | Publication request: Functional diversity in fungal fatty acid synthesis the first acetylenase from the Pacific Golden Chanterelle Cantharellus formosus

Submitted to: Journal of Biological Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 3, 2010
Publication Date: September 10, 2010
Citation: Blacklock, B.J., Scheffler, B.E., Shepard, M.R., Jayasuriya, N., Minto, R.E. 2010. Functional diversity in fungal fatty acid synthesis. The first acetylenase from the Pacific Golden Chanterelle, Cantharellus formosus. Journal of Biological Chemistry. 287(37):28442-28449.

Interpretive Summary: Oil produced from plant seeds has many valuable uses. Modifications of the biochemical pathway can lead to the formation of novel oils in seeds or fatty acid derived compounds which can have important biochemical properties. One major component of interest in these compounds is the degree and position where a fatty acid is saturated or unsaturated (number and position of double or triple bonds with carbon atoms in a fatty acid chain). The evolution of the enzymes involved in producing highly unsaturated fats is not well established. This study examines two genes and their corresponding functional proteins involved in fatty acid production that were isolated and characterized from Pacific Golden Chanterelle (Cantharellus formosus) commonly known as a mushroom. In Chanterelle, these enzymes drive the conversion of the fatty acid oleate through linoleate to the compounds crepenynate and the conjugated enyne (14Z)-dehydrocrepenynate, which are the branchpoint precursors to a major class of unsaturated (acetylenic) natural products.

Technical Abstract: Acetylenic specialized metabolites containing one or more carbon-carbon triple bonds are widespread being found in fungi; vascular and lower plants; marine sponges and algae; and insects. Plants, moss, and most recently, insects have been shown to employ an energetically difficult, sequential dehydrogenative mechanism for acetylenic bond formation. Here, we describe the cloning and heterologous expression in yeast of a linoleoyl 12-desaturase (acetylenase) and a bifunctional desaturase with '12-/''14-regiospecificity from the Pacific golden chanterelle. The acetylenase gene, which is the first identified from a fungus, is phylogenetically distinct from known plant and microfungal desaturases. Together, the bifunctional desaturase and the acetylenase provide the enzymatic activities required to drive oleate through linoleate to crepenynate and the conjugated enyne (14Z)-dehydrocrepenynate, the branchpoint precursors to a major class of acetylenic natural products.