Evolution of the membrane-bound fatty acid desaturases

Alonso, Diego López; Garcı́a-Maroto, Federico; Rodríguez-Ruiz, Juan; Garrido, José Antonio Pérez; Vilches, M.A.

doi:10.1016/s0305-1978(03)00041-3

Cited by 85 publications

(38 citation statements)

References 25 publications

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“…These teleost lineage-specific events and the resulting Fads functional plasticities parallel a similar scenario to that observed in the invertebrate protostome C. elegans [14]. Here, two separate Fads-Δ5/Fads-Δ6 genes are also present and have probably evolved from a Δ6 ancestor [9]. This interchange of functions between Δ6 to Δ5 represents an unusual case of functional plasticity.…”

Section: Discussionsupporting

confidence: 72%

Functional Desaturase Fads1 (Δ5) and Fads2 (Δ6) Orthologues Evolved before the Origin of Jawed Vertebrates

et al. 2012

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Long-chain polyunsaturated fatty acids (LC-PUFAs) such as arachidonic (ARA), eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids are essential components of biomembranes, particularly in neural tissues. Endogenous synthesis of ARA, EPA and DHA occurs from precursor dietary essential fatty acids such as linoleic and α-linolenic acid through elongation and Δ5 and Δ6 desaturations. With respect to desaturation activities some noteworthy differences have been noted in vertebrate classes. In mammals, the Δ5 activity is allocated to the Fads1 gene, while Fads2 is a Δ6 desaturase. In contrast, teleosts show distinct combinations of desaturase activities (e.g. bifunctional or separate Δ5 and Δ6 desaturases) apparently allocated to Fads2-type genes. To determine the timing of Fads1-Δ5 and Fads2-Δ6 evolution in vertebrates we used a combination of comparative and functional genomics with the analysis of key phylogenetic species. Our data show that Fads1 and Fads2 genes with Δ5 and Δ6 activities respectively, evolved before gnathostome radiation, since the catshark Scyliorhinus canicula has functional orthologues of both gene families. Consequently, the loss of Fads1 in teleosts is a secondary episode, while the existence of Δ5 activities in the same group most likely occurred through independent mutations into Fads2 type genes. Unexpectedly, we also establish that events of Fads1 gene expansion have taken place in birds and reptiles. Finally, a fourth Fads gene (Fads4) was found with an exclusive occurrence in mammalian genomes. Our findings enlighten the history of a crucially important gene family in vertebrate fatty acid metabolism and physiology and provide an explanation of how observed lineage-specific gene duplications, losses and diversifications might be linked to habitat-specific food web structures in different environments and over geological timescales.

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Section: Discussionsupporting

confidence: 72%

Functional Desaturase Fads1 (Δ5) and Fads2 (Δ6) Orthologues Evolved before the Origin of Jawed Vertebrates

et al. 2012

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“…There are ample evidences in published literature about bifunctional activity of D12/D15 desaturase [21,22]. Moreover, it is postulated that D12 and D15 desaturases have a common ancestor and there is an evolutionary transition from D12 to D15 desaturase [21,23]. However, the amount of 18:3 we could get was much lower than the amount of 18:2, suggesting weak D15 desaturase activity.…”

Section: Sequence Analysis Of Lufad2-2 Genementioning

confidence: 89%

Cloning of a Novel Omega-6 Desaturase from Flax (Linum usitatissimum L.) and Its Functional Analysis in Saccharomyces cerevisiae

2009

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The Delta12 desaturase represents a diverse gene family in plants and is responsible for conversion of oleic acid (18:1) to linoleic acid (18:2). Several members of this family are known from plants like Arabidopsis and Soybean. Using primers from conserved C- and N-terminal regions, we have cloned a novel Delta12 desaturase gene amplified from flax genomic DNA, denoted as LuFAD2-2. This intron-less gene is 1,149-base pair long encoding 382 amino acids-putative membrane-bound Delta12 desaturase protein. Sequence comparisons show that the novel sequence has 85% similarity with previously reported flax Delta12 desaturase at amino acid level and shows typical features of membrane-bound desaturase such as three conserved histidine boxes along with four membrane-spanning regions that are universally present among plant desaturases. The signature amino acid sequence 'YNNKL' was also found to be present at the N terminus of the protein, which is necessary and sufficient for ER localization of enzyme. Neighbor-Joining tree generated from the sequence alignment grouped LuFAD2-2 among the other FAD2 sequences from Ricinus, Hevea, Jatropha, and Vernicia. When LuFAD2-2 and LuFAD2 were expressed in Saccharomyces cerevisiae, they could convert the oleic acid to linoleic acid, with an average conversion rate of 5.25 and 8.85%, respectively. However, exogenously supplied linoleic acid was feebly converted to linolenic acid suggesting that LuFAD2-2 encodes a functional FAD2 enzyme and has substrate specificity similar to LuFAD2.

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“…Incorporation of the first cis-double bond at the central (C9-C10) position catalyzed by D9-desaturases has an essential effect on membrane physical properties [4], because the balance between saturated and unsaturated fatty acids (UFAs) is, probably, of higher importance than the type of UFA in membrane phospholipids [5]. This event is also a crucial step in polyunsaturated fatty acid (PUFA) synthesis pathways, since all other desaturases require the existence of a previous double bond at the D9 position of the fatty acid [6]. Although a number of integral membrane or membrane-bound D9-desaturase genes have been isolated [7] and the related information was submitted to the public databases, these enzymes are less well understood than the soluble D9-ACP desaturases.…”

Section: Introductionmentioning

confidence: 99%

Identification and Functional Expression of a Δ9‐Fatty Acid Desaturase from Psychrobacter urativorans in Escherichia coli

Yan

Dietrich

Schmid

et al. 2008

Lipids

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The Delta9-fatty acid desaturase is a key enzyme in the synthesis of unsaturated fatty acids. The fatty acid composition of membrane phospholipids in Psychrobacter urativorans is characterized by a high degree of desaturation at Delta9 position. Based on CODEHOP-mediated PCR strategy, a novel gene designated as PuFAD9, putatively encoding a Delta9-fatty acid desaturase (PuFAD9), was isolated from P. urativorans. The gene consists of 1,455 bp and codes for 484 amino acids. Analysis of the amino acid sequence reveals three histidine clusters and a hydropathy profile, typical for membrane-bound desaturases. Activity of the PuFAD9 protein, recombinantly expressed in Escherichia coli was confirmed by GC-MS analysis of the cellular fatty acid composition. It was found that the ratio between palmitoleic and palmitic acid in E. coli cells heterologously expressing the PuFAD9 gene was significantly affected by IPTG induction and the growth temperature.

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Evolution of the membrane-bound fatty acid desaturases

Cited by 85 publications

References 25 publications

Functional Desaturase Fads1 (Δ5) and Fads2 (Δ6) Orthologues Evolved before the Origin of Jawed Vertebrates

Functional Desaturase Fads1 (Δ5) and Fads2 (Δ6) Orthologues Evolved before the Origin of Jawed Vertebrates

Cloning of a Novel Omega-6 Desaturase from Flax (Linum usitatissimum L.) and Its Functional Analysis in Saccharomyces cerevisiae

Identification and Functional Expression of a Δ9‐Fatty Acid Desaturase from Psychrobacter urativorans in Escherichia coli

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