Molecular Mechanism of Interaction Between Fatty Acid Delta 6 Desaturase and Acyl-CoA by Computational Prediction

Enzyme catalyzed desaturation of intracellular fatty acids plays an important role in various physiological and pathological processes related to lipids. Limited to the multiple transmembrane domains, it is difficult to obtain their three-dimensional structure of fatty acid desaturases. So how they interact with their substrates is unclear. Here, we predicted the complex of Micromonas pusilla delta 6 desaturase (MpFADS6) with the substrate linoleinyl-CoA (ALA-CoA) by trRosetta software and docking poses by Dock 6 software. The potential enzyme-substrate binding sites were anchored by analysis of the complex. Then, site-directed mutagenesis and activity verification clarified that W290, W224, and F352 were critical residues of the substrate tunnel and directly bonded to ALA-CoA. H94 and H69 were indispensable for transporting electrons with heme. H452, N445, and H358 significantly influenced the recognition and attraction of MpFADS6 to the substrate. These findings provide new insights and methods to determine the structure, mechanisms and directed transformation of membrane-bound desaturases.

Engineering and Fermenter Optimization of Fungi GLA Productions in Pichia Pastoris GS115 Using Oil Waste

γ-Linolenic acid (GLA) is an important n-6 polyunsaturated fatty acid (PUFA) that has received considerable attention in both levels in human and animal feed. GLA is used in many nutritional and medicinal applications such as the treatment of cancer, inflammatory disorders, and diabetes. Currently, plant seed is the main dietary source of GLA that is not enough to utilize on an industrial scale. To generate a sustainable novel source of GLA, the gene of delta-6 desaturase, which is one of the important enzymes in the GLA production pathway was isolated from Mucor rouxii DSM1194 and expressed in Pichia pastoris GS115 by pPICZC vector. The recombinant yeast expressed the GLA up to 19.2% (72 mg/g) of total fatty acids. GLA production of recombinant yeast was studied in fermenter by oil waste along 5 days and results detected 6.3 g / l lipid and 103 mg/g GLA was produced in 72 hours. The present study may provide an opportunity for the development of an alternative host for manufacturing GLA on an industrial scale.

An Integrated Approach to Produce a Recombinant Yeast Pichia Pastoris For GLA Production

γ-Linolenic acid (GLA) is an important n-6 polyunsaturated fatty acid (PUFA) used in many nutritional and medicinal applications such as the treatment of cancer, inflammatory disorders, and diabetes. However, GLA level of the total fatty acids in plant seeds and nuts as prominent sources of GLA is not enough to utilize on an industrial scale. The study aimed to improve the expression of delta-6 desaturase, which is one of the important enzymes in GLA production pathway. The expression vector pPICZC was selected for clone M.rouxii delta-6 desaturase. The engineered vector was first cloned into E. coli DH5α and after plasmid extraction and confirmation of sequencing was transformed by electroporation into Pichia pastoris GS115. The results indicated that the recombinant yeast strain expressed the gene in the presence of methanol 0.5%. The lipids and essential fatty acids especially GLA were extracted to confirm the expression. The results of studies of lipid and fatty acid production by Sudan black and Nile red staining, GC, and flow cytometry revealed that recombinant strain can produce GLA levels up to 19.2% of total fatty acids. The present study may provide an opportunity for the development of an alternative host for manufacturing GLA on an industrial scale.

Palmitoleic and Dihomo-γ-Linolenic Acids Are Positively Associated With Abdominal Obesity and Increased Metabolic Risk in Children

Background: The impact of abdominal obesity (AO) on plasma fatty acid changes and cardiometabolic risk in children who are obese and overweight has rarely been investigated. This study determined whether plasma fatty acid composition differed between children with AO and those without AO and its relationship with metabolic risk, particularly in the obese and overweight groups.Methods: A total of 181 schoolchildren (aged 7–18 years) were included. Anthropometric and biochemical data and plasma fatty acid profiles were analyzed, and the indices of desaturase activity were estimated. Children were categorized based on their body weight and AO status. A continuous metabolic risk score was calculated using the sum of the z-scores of metabolic variables. A one-way analysis of variance test was used to compare the composition ratio of fatty acids between children with and without AO in the obese and overweight groups and normal-weight controls. Pearson analysis was also used to explore significant fatty acid and desaturase indicators associated with metabolic abnormalities.Results: Children who were obese and overweight (N = 126) displayed higher dihomo-γ-linolenic acid (20:3n-6) and γ-linolenic acid (18:3n-6) proportions than normal-weight controls (N = 55), but lower heptadecanoic acid (17:0) proportion, regardless of the AO status of each individual. Obese and overweight children with AO (N = 89), but not their non-AO counterparts (N = 37), exhibited a significantly higher proportion of palmitoleic acid (16:1n-7) than the remaining study groups. Pearson analysis showed that high proportions of palmitoleic acid and dihomo-γ-linolenic acid, as well as increased stearoyl-coenzyme A desaturase-1(16) and delta-6 desaturase and decreased delta-5 desaturase activities, are strongly correlated with weight-height ratio, homeostasis model of assessment values for insulin resistance, hypertriglyceridemia, and continuous metabolic risk scores.Conclusion: Higher palmitoleic acid and dihomo-γ-linolenic acid proportions, as well as increased stearoyl-coenzyme A desaturase-1(16) and delta-6 desaturase and decreased delta-5 desaturase activities are associated with AO and increased metabolic risk in children who are obese and overweight.

IN SILICO ANALYSIS OF DELTA 6 DESATURASE - A KEY ENZYME FOR OMEGA €“3/6€“ FATTY ACID PRODUCTION

Delta 6 desaturase is a key enzyme involved in the production of omega 3/6 fatty acids and it is the rate-limiting step. The study aims to characterize the delta 6 desaturase enzyme and to find the binding affinity of various ligand with the protein by docking. It is found that delta 6 desaturase enzyme sequence is very unique and has less similarity with the other desaturase protein. The structural analysis was performed by Ramachandran plot and SCOPe structure prediction. Modeller is used to determine the DOPE score of the selected enzyme. The lowest DOPE score protein is chosen to determine the binding affinity of ligand molecules. Three different ligands were selected and its interaction was determined by the PyRX - Autodock Vina. These studies will give a better idea of the interaction of various molecules, which help to deduce its function by further experimentation.

A Functional 3′ UTR Polymorphism of FADS2 Affects Cow Milk Composition through Modifying Mir-744 Binding

This study determined the associations of FADS2 c.1571G>A with milk FAs content and revealed that cows with the GG genotype had improved levels of delta-6 desaturase substrates (linoleic acid, C18:2n-6; p < 0.001) and decreased levels of desaturase products (gamma-linolenic acid, C18:3n-6; p < 0.001), indicating a reduction in FADS2 expression or delta-6 desaturase activity caused by this polymorphism. Computer alignment demonstrated that c.1571G>A occurred within a potential miR-744 binding site. When the c.1571G allele was present, the luciferase activity of reporter constructs was significantly suppressed by miR-744, while no such effect was observed with the A allele. Overexpression of miR-744 in bovine mammary epithelial cells (with the 1571GG genotype) downregulated FADS2 expression at both mRNA and protein levels. In contrast, inhibition of endogenous miR-744 with a specific inhibitor dramatically upregulated FADS2 expression. Taken together, these lines of evidence indicated that the c.1571A minor allele abolished the ability of miR-744 to bind FADS2, with a consequent increase in FADS2 expression levels and synthesis of omega-6 LC-PUFAs.