Structure of a Specialized Acyl Carrier Protein Essential for Lipid A Biosynthesis with Very Long-Chain Fatty Acids in Open and Closed Conformations

ABSTRACT Free-living Sinorhizobium meliloti lpxXL and acpXL mutants lack lipid A very-long-chain fatty acids (VLCFAs) and have reduced competitiveness in alfalfa. We demonstrate that LpxXL and AcpXL play important but distinct roles in bacteroid development and that LpxXL is essential for the modification of S. meliloti bacteroid lipid A with VLCFAs.

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Chimeric Fatty Acyl-Acyl Carrier Protein Thioesterases Provide Mechanistic Insight into Enzyme Specificity and Expression

Applied and Environmental Microbiology ◽

10.1128/aem.02868-17 ◽

2018 ◽

Vol 84 (10) ◽

Cited By ~ 6

Author(s):

Marika Ziesack ◽

Nathan Rollins ◽

Aashna Shah ◽

Brendon Dusel ◽

Gordon Webster ◽

...

Keyword(s):

Fatty Acids ◽

Fatty Acid ◽

Acyl Carrier Protein ◽

Fatty Acyl ◽

Carrier Protein ◽

Fatty Acid Production ◽

Medium Chain ◽

Commodity Chemicals ◽

Long Chain ◽

Chain Fatty Acids

ABSTRACT Medium-chain fatty acids are commodity chemicals. Increasing and modifying the activity of thioesterases (TEs) on medium-chain fatty acyl-acyl carrier protein (acyl-ACP) esters may enable a high-yield microbial production of these molecules. The plant Cuphea palustris harbors two distinct TEs: C. palustris FatB1 ( Cp FatB1) (C 8 specificity, lower activity) and Cp FatB2 (C 14 specificity, higher activity) with 78% sequence identity. We combined structural features from these two enzymes to create several chimeric TEs, some of which showed nonnatural fatty acid production as measured by an enzymatic assay and gas chromatography-mass spectrometry (GC-MS). Notably, chimera 4 exhibited an increased C 8 fatty acid production in correlation with improved microbial expression. This chimera led us to identify Cp FatB2-specific amino acids between positions 219 and 272 that lead to higher protein levels. Chimera 7 produced a broad range of fatty acids and appeared to combine a fatty acid binding pocket with long-chain specificity and an ACP interaction site that may activate fatty acid extrusion. Using homology modeling and in silico docking with ACP, we identified a “positive patch” within amino acids 162 to 218, which may direct the ACP interaction and regulate access to short-chain fatty acids. On the basis of this modeling, we transplanted putative ACP interaction sequences from Cp FatB1 into Cp FatB2 and created a chimeric thioesterase that produced medium-chain as well as long-chain fatty acids. Thus, the engineering of chimeric enzymes and characterizing their microbial activity and chain-length specificity suggested mechanistic insights into TE functions and also generated thioesterases with potentially useful properties. These observations may inform a rational engineering of TEs to allow alkyl chain length control. IMPORTANCE Medium-chain fatty acids are important commodity chemicals. These molecules are used as plastic precursors and in shampoos and other detergents and could be used as biofuel precursors if production economics were favorable. Hydrocarbon-based liquid fuels must be optimized to have a desired boiling point, low freezing point, low viscosity, and other physical characteristics. Similarly, the solubility and harshness of detergents and the flexibility of plastic polymers can be modulated. The length and distribution of the carbon chains in the hydrophobic tails determine these properties. The biological synthesis of cell membranes and fatty acids produces chains of primarily 16 to 18 carbons, which give rise to current biofuels. The ultimate goal of the work presented here is to engineer metabolic pathways to produce designer molecules with the correct number of carbons in a chain, so that such molecules could be used directly as specialty commodity chemicals or as fuels after minimal processing.

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Diet supplemented with medium- and long-chain fatty acids does not affect lower GI motility and visceral pain in rats

10.26226/morressier.59a6b345d462b80290b5487f ◽

2017 ◽

Author(s):

Paula Mosinska

Keyword(s):

Fatty Acids ◽

Visceral Pain ◽

Long Chain Fatty Acids ◽

Long Chain ◽

Chain Fatty Acids ◽

Gi Motility

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Binding of bilirubin and long-chain fatty acids to human serum albumin with general remarks on displacement of firmly bound ligands

Scandinavian Journal of Clinical and Laboratory Investigation ◽

10.3109/00365517709091491 ◽

1977 ◽

Vol 37 (3) ◽

pp. 257-266 ◽

Cited By ~ 8

Author(s):

R. Brodersen ◽

L. Funding

Keyword(s):

Fatty Acids ◽

Human Serum Albumin ◽

Serum Albumin ◽

Human Serum ◽

Long Chain Fatty Acids ◽

Long Chain ◽

Chain Fatty Acids

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Differential Effects of Fatty Acid Saturation and Chain Length on NASH in Juvenile Iberian Pigs

Current Developments in Nutrition ◽

10.1093/cdn/nzaa050_005 ◽

2020 ◽

Vol 4 (Supplement_2) ◽

pp. 682-682 ◽

Cited By ~ 1

Author(s):

Kayla Dillard ◽

Morgan Coffin ◽

Gabriella Hernandez ◽

Victoria Smith ◽

Catherine Johnson ◽

...

Keyword(s):

Fatty Acids ◽

Body Weight ◽

Fatty Acid ◽

Liver Injury ◽

Olive Oil ◽

Coconut Oil ◽

Long Chain Fatty Acids ◽

Medium Chain ◽

Long Chain ◽

Chain Fatty Acids

Abstract Objectives Non-alcoholic fatty liver disease (NAFLD) represents the major cause of pediatric chronic liver pathology in the United States. The objective of this study was to compare the relative effect of inclusion of isocaloric amounts of saturated medium-chain fatty acids (hydrogenated coconut oil), saturated long-chain fatty acids (lard) and unsaturated long-chain fatty acids (olive oil) on endpoints of NAFLD and insulin resistance. Methods Thirty-eight 15-d-old Iberian pigs were fed 1 of 4 diets containing (g/kg body weight × d) 1) control (CON; n = 8): 0 g fructose, 10.5 g fat, and 187 kcal metabolizable energy (ME), 2) lard (LAR; n = 10): 21.6 g fructose, 17.1 g fat (100% lard) and 299 kcal ME, 3) hydrogenated coconut oil (COCO; n = 10): 21.6 g fructose, 16.9 g fat (42.5% lard and 57.5% coconut oil) and 299 kcal ME, and 4) olive oil (OLV, n = 10): 21.6 g fructose, 17.1 g fat (43.5% lard and 56.5% olive oil) and 299 kcal ME, for 9 consecutive weeks. Body weight was recorded every 3 d. Serum markers of liver injury and dyslipidemia were measured on d 60 at 2 h post feeding, with all other serum measures assessed on d 70. Liver tissue was collected on d 70 for histology, triacylglyceride (TG) quantification, and metabolomics analysis. Results Tissue histology indicated the presence of steatosis in LAR, COCO and OLV compared with CON (P ≤ 0.001), with a further increase in in non-alcoholic steatohepatitis (NASH) in OLV and COCO compared with LAR (P ≤ 0.01). Alanine and aspartate aminotransferases were higher in COCO and OLV (P ≤ 0.01) than CON. All treatment groups had lower liver concentrations of methyl donor's choline and betaine versus CON, while bile acids were differentially changed (P ≤ 0.05). COCO had higher levels of TGs with less carbons (Total carbons < 52) than all other groups (P ≤ 0.05). Several long-chain acylcarnitines involved in fat oxidation were higher in OLV versus all other groups (P ≤ 0.05). Conclusions Inclusion of fats enriched in medium-chain saturated and long-chain unsaturated fatty acids in a high-fructose high-fat diet increased liver injury, compared with fats with a long-chain saturated fatty acid profile. Further research is required to investigate the mechanisms causing this difference in physiological response to these dietary fat sources. Funding Sources ARI, AcornSeekers.

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