Abstract
Numerous Δ12-, Δ15- and multifunctional membrane fatty acid desaturases (FADs) have been identified in fungi, revealing great variability in the enzymatic specificities of FADs involved in biosynthesis of polyunsaturated fatty acids (PUFAs). Here, we report gene isolation and characterization of novel Δ12/Δ15- and Δ15-FADs named CpFad2 and CpFad3, respectively, from the opportunistic pathogenic yeast Candida parapsilosis. Overexpression of CpFad3 in Saccharomyces cerevisiae strains supplemented with linoleic acid (Δ9,Δ12-18:2) and hexadecadienoic acid (Δ9,Δ12-16:2) leads to accumulation of Δ15-PUFAs, i.e., α-linolenic acid (Δ9,Δ12,Δ15-18:3) and hexadecatrienoic acid with an unusual terminal double bond (Δ9,Δ12,Δ15-16:3). CpFad2 produces a range of Δ12- and Δ15-PUFAs. The major products of CpFad2 are linoleic and hexadecadienoic acid (Δ9,Δ12-16:2), accompanied by α-linolenic acid and hexadecatrienoic acid (Δ9,Δ12,Δ15-16:3). Using GC/MS analysis of trimethylsilyl derivatives, we identified ricinoleic acid (12-hydroxy-9-octadecenoic acid) as an additional product of CpFad2. These results demonstrate that CpFAD2 is a multifunctional FAD and indicate that detailed analysis of fatty acid derivatives might uncover a range of enzymatic selectivities in other Δ12-FADs from budding yeasts (Ascomycota: Saccharomycotina).
Highlights
Unsaturated fatty acids (UFAs) play a key role in maintenance of optimal physical and biological properties of cell membranes [1]
We have investigated the effect of accumulation of polyunsaturated fatty acids (PUFAs) in the CpFAD2 and CpFAD3 strains on their growth rate and tolerance to alkali
The relative amount of fatty acids is expressed as a percentage of total fatty acid methyl esters
Summary
Unsaturated fatty acids (UFAs) play a key role in maintenance of optimal physical and biological properties of cell membranes [1]. The main regioselective modes are: (1) the double bond is introduced between specific carbon atoms counted from the carboxy terminus (DX) or (2) methyl terminus (vX) of the fatty acyl substrate, and (3) a subsequent double bond is introduced a specific number of carbon atoms (usually three) counted from the pre-existing double bond (n+3) [3] These FAD regioselectivities are not mutually exclusive, and Meesapyodsuk et al [4] suggested assigning them primary and secondary modes to more precisely describe FAD regioselectivity. Multifunctional FADs preferentially producing D9,D12-18:2 and D9,D12-16:2 from D9-UFAs and capable of producing minor amounts of D9,D12,D15-18:3 and D9,D12,D15-16:3 might be termed as v+3 (D12), indicating that the primary desaturase regioselectivity is v+3 and the preferred regioselectivity is D12 This nomenclature may require detailed information on FAD diagnostic substrates and products, which are often not available in the literature. We will adhere to nomenclature designating FADs as D12- and/or D15-FADs
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
