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1.
Ultrason Sonochem ; 108: 106981, 2024 Aug.
Article de Anglais | MEDLINE | ID: mdl-38981339

RÉSUMÉ

This study examined the impacts of ultrasonic power (0, 150, 300, 450, 600, and 750 W) and ultrasonic durations (3, 6, 9, 12, and 15 min) on the physicochemical properties and microstructure of diacylglycerol (DAG)-loaded emulsions stabilized with soybean protein isolate (SPI) and sodium alginate (SA). The findings indicated that the smallest particle size, zeta potential, and contact angle for SPI-SA-DAG emulsions were respectively 5.58 µm, -49.85 mV, and 48.65°, achieved at an ultrasonic power of 450 W. The emulsification properties, loss modulus, storage modulus, and apparent viscosity of the emulsions were optimal at this power setting and at a duration of 9 min. Analytical techniques, including confocal laser scanning-, scanning electron-, and atomic force microscopy, revealed that ultrasonication significantly altered emulsion aggregation state, with the surface roughness (Rq) being minimized at 450 W. These results demonstrated that the stability of SPI-SA-DAG emulsions can be effectively enhanced by an appropriate ultrasonic treatment at 450 W for 9 min. This research provides theoretical support for the broad application of sonication techniques in the food industry.


Sujet(s)
Alginates , Diglycéride , Émulsions , Protéines de soja , Alginates/composition chimique , Protéines de soja/composition chimique , Diglycéride/composition chimique , Sonication , Acides hexuroniques/composition chimique , Acide glucuronique/composition chimique , Phénomènes chimiques , Taille de particule , Ondes ultrasonores
2.
Food Chem ; 455: 139901, 2024 Oct 15.
Article de Anglais | MEDLINE | ID: mdl-38833858

RÉSUMÉ

This research develops diacylglycerol (DAG) based Pickering emulsions with enhanced oxidative stability stabilized by self-assembled quercetin/DAG/ß-cyclodextrin (ß-CD) complexes (QDCCs) using a one-step agitation method. Influence of DAG content (5%, 15%, 40%, and 80%, w/w) on the self-assembly behavior, interfacial properties, and emulsifying ability of complex particles was investigated. SEM, XRD and ATR-FTIR studies confirmed the formation of ternary composite particles. QDCCs in 80% DAG oil had the highest quercetin encapsulation efficiency (6.09 ± 0.01%), highest DPPH radical scavenging rate and ferric reducing antioxidant property (FRAP). ß-CD and quercetin adsorption rates in emulsion with 80% DAG oil were 88.4 ± 2.53% and 98.34 ± 0.15%, respectively. Pickering emulsions with 80% DAG had the smallest droplet size (8.90 ± 1.87 µm) and excellent oxidation stability. This research develops a novel approach to regulate the physicochemical stability of DAG-based emulsions by anchoring natural antioxidants at the oil-water interface through a one-pot self-assembly method.


Sujet(s)
Antioxydants , Diglycéride , Émulsions , Taille de particule , Quercétine , Cyclodextrines bêta , Émulsions/composition chimique , Quercétine/composition chimique , Cyclodextrines bêta/composition chimique , Diglycéride/composition chimique , Antioxydants/composition chimique , Émulsifiants/composition chimique , Oxydoréduction
3.
Colloids Surf B Biointerfaces ; 239: 113955, 2024 Jul.
Article de Anglais | MEDLINE | ID: mdl-38754200

RÉSUMÉ

Lipid-based drug delivery systems offer the potential to enhance bioavailability, reduce dosing frequency, and improve patient adherence. In aqueous environment, initially dry lipid depots take up water and form liquid crystalline phases. Variation of lipid composition, depot size and hydration-induced phase transitions will plausibly affect the diffusion in and out of the depot. Lipid depots of soybean phosphatidylcholine (SPC) and glycerol dioleate (GDO) mixtures were hydrated for varying time durations in a phosphate-buffered saline (PBS) buffer and then analyzed with Karl Fischer titration, magnetic resonance imaging (MRI) and gravimetrically. Mathematical modeling of the swelling process using diffusion equations, was used to estimate the parameters of diffusion. Both composition of lipid mixture and depot size affect swelling kinetics… The diffusion parameters obtained in Karl Fischer titration and MRI (with temporal and spatial resolution respectively) are in good agreement. Remarkably, the MRI results show a gradient of water content within the depot even after the end of diffusion process. Apparently contradicting the first Fick's law in its classical form, these results find an explanation using the generalized Fick's law that considers the gradient of chemical potential rather than concentration as the driving force of diffusion.


Sujet(s)
Glycine max , Phosphatidylcholines , Phosphatidylcholines/composition chimique , Glycine max/composition chimique , Cinétique , Diffusion , Eau/composition chimique , Imagerie par résonance magnétique , Diglycéride/composition chimique
4.
ACS Infect Dis ; 10(6): 2250-2261, 2024 Jun 14.
Article de Anglais | MEDLINE | ID: mdl-38771724

RÉSUMÉ

Toward human immunodeficiency virus type-1 (HIV-1) cure, cells latently infected with HIV-1 must be eliminated from people living with HIV-1. We previously developed a protein kinase C (PKC) activator, diacylglycerol (DAG)-lactone derivative 3, with high HIV-1 latency-reversing activity, based on YSE028 (2) as a lead compound and found that the activity was correlated with binding affinity for PKC and stability against esterase-mediated hydrolysis. Here, we synthesized new DAG-lactone derivatives not only containing a tertiary ester group or an isoxazole surrogate but also several symmetric alkylidene moieties to improve HIV-1 latency reversing activity. Compound 9a, with a dimethyl group at the α-position of the ester group, exerted twice higher HIV-1 latency reversing activity than compound 3, and compound 26, with the isoxazole moiety, was significantly active. In addition, DAG-lactone derivatives with moderate hydrophobicity and potent biostability showed high biological activity.


Sujet(s)
Agents antiVIH , VIH-1 (Virus de l'Immunodéficience Humaine de type 1) , Lactones , Latence virale , Humains , VIH-1 (Virus de l'Immunodéficience Humaine de type 1)/effets des médicaments et des substances chimiques , VIH-1 (Virus de l'Immunodéficience Humaine de type 1)/physiologie , Latence virale/effets des médicaments et des substances chimiques , Lactones/pharmacologie , Lactones/composition chimique , Lactones/synthèse chimique , Agents antiVIH/pharmacologie , Agents antiVIH/composition chimique , Agents antiVIH/synthèse chimique , Diglycéride/composition chimique , Diglycéride/pharmacologie , Diglycéride/synthèse chimique , Infections à VIH/traitement médicamenteux , Infections à VIH/virologie , Protéine kinase C/métabolisme , Protéine kinase C/antagonistes et inhibiteurs
5.
Int J Biol Macromol ; 271(Pt 2): 132592, 2024 Jun.
Article de Anglais | MEDLINE | ID: mdl-38820905

RÉSUMÉ

Torreya grandis wax (TGW), a new nut wax and by-product of refined Torreya grandis oil, lacks sufficient research and application. In this study, the gelling behavior in diacylglycerol (DAG) and chemical compositions of TGW were investigated. Compared with four typical natural waxes, TGW exhibited the lowest critical gelling concentration (Cg, 1 %wt) in DAG. The results performed that TGW-DAG oleogels at Cg possessed the highest G'LVR and G″, highest critical stress, good thermal stability, moderate viscosity recovery, and osc. yields stress, indicating strong gel. The microstructure and correlation analysis revealed that excellent gelling behaviors of TGW-DAG oleogels were due to the solid three-dimensional network formed by rod-like TGW crystal, and the higher hydrocarbon compound (HC) content and HC/wax ester in TGW. Formulation optimization suggested that oleogel containing 3.2 % TGW and 1.0 % diosgenin (DSG) better mimicked the characteristics of shortening in terms of hardness, adhesiveness, spreadability. The bread prepared with TGW/DSG-DAG oleogel owned uniform and dense pores, the best moisture retention capability, and soft and firm taste, demonstrating that TGW/DSG-DAG oleogel was a good shortening substitute. Therefore, this study provides the systematically fundamental knowledge of TGW and develops DSG-TGW-DAG oleogels as promising shortening substitutions.


Sujet(s)
Diglycéride , Gels , Composés chimiques organiques , Cires , Cires/composition chimique , Diglycéride/composition chimique , Composés chimiques organiques/composition chimique , Gels/composition chimique , Viscosité , Rhéologie
6.
Cell Chem Biol ; 31(7): 1336-1348.e7, 2024 Jul 18.
Article de Anglais | MEDLINE | ID: mdl-38582083

RÉSUMÉ

Phospholipase C (PLC) is a key enzyme that regulates physiological processes via lipid and calcium signaling. Despite advances in protein engineering, no tools are available for direct PLC control. Here, we developed a novel optogenetic tool, light-controlled PLCß (opto-PLCß). Opto-PLCß uses a light-induced dimer module, which directs an engineered PLC to the plasma membrane in a light-dependent manner. Our design includes an autoinhibitory capacity, ensuring stringent control over PLC activity. Opto-PLCß triggers reversible calcium responses and lipid dynamics in a restricted region, allowing precise spatiotemporal control of PLC signaling. Using our system, we discovered that phospholipase D-mediated phosphatidic acid contributes to diacylglycerol clearance on the plasma membrane. Moreover, we extended its applicability in vivo, demonstrating that opto-PLCß can enhance amygdala synaptic plasticity and associative fear learning in mice. Thus, opto-PLCß offers precise spatiotemporal control, enabling comprehensive investigation of PLC-mediated signaling pathways, lipid dynamics, and their physiological consequences in vivo.


Sujet(s)
Lumière , Plasticité neuronale , Animaux , Souris , Humains , Phospholipase C beta/métabolisme , Souris de lignée C57BL , Optogénétique , Type C Phospholipases/métabolisme , Membrane cellulaire/métabolisme , Mâle , Cellules HEK293 , Diglycéride/métabolisme , Diglycéride/composition chimique , Calcium/métabolisme , Acides phosphatidiques/métabolisme , Acides phosphatidiques/composition chimique
7.
Bioprocess Biosyst Eng ; 47(5): 697-712, 2024 May.
Article de Anglais | MEDLINE | ID: mdl-38536484

RÉSUMÉ

Mono- and diglycerides play a crucial role in the food industry as multifunctional food additives and emulsifiers. Their importance stems from their unique properties, which allow them to improve the quality, texture, and stability of various food products. Here, results of the kinetic modeling of the mono- and diglycerides synthesis mediated by the lipase Lipozyme® TL 100 L immobilized on the clayey support Spectrogel® type C are reported. The support was characterized by TEM, SEM, and FTIR. Firstly, the influence of pH and lipase load on the immobilization process was analyzed, resulting in an enzymatic activity of 93.2 ± 0.7 U g-1 under optimized conditions (170.9 U g-1 of lipase and pH of 7.1). Afterward, the effects of reaction temperature and concentration of immobilized biocatalyst in the feedstock conversion were evaluated. At optimized parameters, a triglycerides conversion of 97% was obtained at 36.5 °C, 7.9 vol.% of enzyme, a glycerol to feedstock molar ratio of 2:1, and 2 h. The optimized conditions were used to determine the kinetic constants of the elementary reactions involved in the glycerolysis, where a fit superior to 0.99 was achieved between experimental values and predicted data.


Sujet(s)
Enzymes immobilisées , Triacylglycerol lipase , Triacylglycerol lipase/composition chimique , Triacylglycerol lipase/métabolisme , Enzymes immobilisées/composition chimique , Cinétique , Diglycéride/composition chimique , Diglycéride/biosynthèse , Argile/composition chimique , Concentration en ions d'hydrogène , Température , Modèles chimiques
8.
Chembiochem ; 25(10): e202300808, 2024 May 17.
Article de Anglais | MEDLINE | ID: mdl-38400776

RÉSUMÉ

The process of protein transport across membranes involves a variety of factors and has been extensively investigated. Traditionally, proteinaceous translocons and chaperones have been recognized as crucial factors in this process. However, recent studies have highlighted the significant roles played by lipids and a glycolipid present in biological membranes in membrane protein transport. Membrane lipids can influence transport efficiency by altering the physicochemical properties of membranes. Notably, our studies have revealed that diacylglycerol (DAG) attenuates mobility in the membrane core region, leading to a dramatic suppression of membrane protein integration. Conversely, a glycolipid in Escherichia coli inner membranes, named membrane protein integrase (MPIase), enhances integration not only through the alteration of membrane properties but also via direct interactions with membrane proteins. This review explores the mechanisms of membrane protein integration mediated by membrane lipids, specifically DAG, and MPIase. Our results, along with the employed physicochemical analysis methods such as fluorescence measurements, nuclear magnetic resonance, surface plasmon resonance, and docking simulation, are presented to elucidate these mechanisms.


Sujet(s)
Membrane cellulaire , Escherichia coli , Glycolipides , Transport des protéines , Glycolipides/métabolisme , Glycolipides/composition chimique , Escherichia coli/métabolisme , Membrane cellulaire/métabolisme , Protéines membranaires/métabolisme , Protéines membranaires/composition chimique , Protéines Escherichia coli/métabolisme , Protéines Escherichia coli/composition chimique , Diglycéride/métabolisme , Diglycéride/composition chimique
9.
Nat Struct Mol Biol ; 31(6): 884-895, 2024 Jun.
Article de Anglais | MEDLINE | ID: mdl-38388831

RÉSUMÉ

Sphingomyelin (SM) has key roles in modulating mammalian membrane properties and serves as an important pool for bioactive molecules. SM biosynthesis is mediated by the sphingomyelin synthase (SMS) family, comprising SMS1, SMS2 and SMS-related (SMSr) members. Although SMS1 and SMS2 exhibit SMS activity, SMSr possesses ceramide phosphoethanolamine synthase activity. Here we determined the cryo-electron microscopic structures of human SMSr in complexes with ceramide, diacylglycerol/phosphoethanolamine and ceramide/phosphoethanolamine (CPE). The structures revealed a hexameric arrangement with a reaction chamber located between the transmembrane helices. Within this structure, a catalytic pentad E-H/D-H-D was identified, situated at the interface between the lipophilic and hydrophilic segments of the reaction chamber. Additionally, the study unveiled the two-step synthesis process catalyzed by SMSr, involving PE-PLC (phosphatidylethanolamine-phospholipase C) hydrolysis and the subsequent transfer of the phosphoethanolamine moiety to ceramide. This research provides insights into the catalytic mechanism of SMSr and expands our understanding of sphingolipid metabolism.


Sujet(s)
Cryomicroscopie électronique , Modèles moléculaires , Sphingomyéline , Transferases (other substituted phosphate groups) , Humains , Transferases (other substituted phosphate groups)/métabolisme , Transferases (other substituted phosphate groups)/composition chimique , Sphingomyéline/métabolisme , Sphingomyéline/composition chimique , Sphingomyéline/biosynthèse , Céramides/métabolisme , Céramides/composition chimique , Éthanolamines/métabolisme , Éthanolamines/composition chimique , Phosphatidyléthanolamine/métabolisme , Phosphatidyléthanolamine/composition chimique , Diglycéride/métabolisme , Diglycéride/composition chimique , Protéines de tissu nerveux/métabolisme , Protéines de tissu nerveux/composition chimique , Protéines membranaires
10.
Food Chem ; 427: 136696, 2023 Nov 30.
Article de Anglais | MEDLINE | ID: mdl-37392626

RÉSUMÉ

Diacylglycerols (DAG) of varying chain lengths were synthesized and the acyl migrated samples with different 1,3-DAG/1,2-DAG ratios were obtained. The crystallization profile and surface adsorption differed depending on DAG structure. C12 and C14 DAGs formed small platelet- and needle-like crystals at the oil-air interface which can better reduce surface tension and pack in an ordered lamellar structure in oil. The acyl migrated DAGs with higher ratios of 1,2-DAG showed reduced crystal size and lower oil-air interfacial activity. C14 and C12 DAG oleogels exhibited higher elasticity and whipping ability with crystal shells surrounding bubbles, whereas C16 and C18 DAG oleogels had low elasticity and limited whipping ability due to the formation of aggregated needle-like crystals and loose gel network. Thus, acyl chain length dramatically influences the gelation and foaming behaviors of DAGs whereas the isomers exert little influence. This study provides basis for applying DAG of different structures in food products.


Sujet(s)
Diglycéride , Composés chimiques organiques , Diglycéride/composition chimique , Isomérie , Composés chimiques organiques/composition chimique , Cristallisation
11.
Methods Enzymol ; 683: 191-224, 2023.
Article de Anglais | MEDLINE | ID: mdl-37087188

RÉSUMÉ

Diacylglycerols (DAGs) are anabolic precursors to membrane lipid and storage triacylglycerol biosynthesis, metabolic intermediates of lipid catabolism, and potent cellular signaling molecules. The different DAG molecular species that accumulate over development or in different tissues reflect the changing aspects of cellular lipid metabolism. Consequently, an accurate determination of DAG molecular species in biological samples is essential to understand various metabolic processes and their diagnostic relevance. However, quantification of DAG molecular species in various biological samples represents a challenging task because of their low abundance, hydrophobicity, and instability. This chapter describes the most common chromatographic (TLC and HPLC) and mass spectrometry (MS) methods used to analyze DAG molecular species. In addition, we directly compared the three methods using DAG obtained by phospholipase C hydrolysis of phosphatidylcholine purified from a Nicotiana benthamiana leaf extract. We conclude that each method identified similar major molecular species, however, the exact levels of those varied mainly due to sensitivity of the technique, differences in sample preparation, and processing. This chapter provides three different methods to analyze DAG molecular species, and the discussion of the benefits and challenges of each technique will aid in choosing the right method for your analysis.


Sujet(s)
Diglycéride , Spectrométrie de masse ESI , Diglycéride/analyse , Diglycéride/composition chimique , Diglycéride/métabolisme , Chromatographie en phase liquide à haute performance/méthodes , Spectrométrie de masse ESI/méthodes , Phosphatidylcholines
12.
Ultrason Sonochem ; 95: 106354, 2023 May.
Article de Anglais | MEDLINE | ID: mdl-36898248

RÉSUMÉ

The study aimed to evaluate the effect of ultrasonic pretreatment on the transesterification of lard with glycerol monolaurate (GML) using Lipozyme TL IM to synthesize diacylglycerol (DAG), and the physicochemical properties of lard, GML, ultrasonic-treated diacylglycerol (named U-DAG), purified ultrasonic-treated diacylglycerol obtained by molecular distillation (named P-U-DAG), and without ultrasonic-treated diacylglycerol (named N-U-DAG) were analyzed. The optimized ultrasonic pretreatment conditions were: lard to GML mole ratio 3:1, enzyme dosage 6 %, ultrasonic temperature 80 °C, time 9 min, power 315 W. After ultrasonic pretreatment, the mixtures reacted for 4 h in a water bath at 60 °C, the content of DAG reached 40.59 %. No significant variations were observed between U-DAG and N-U-DAG in fatty acids compositions and iodine value, while P-U-DAG had lower unsaturated fatty acids than U-DAG. Differential scanning calorimetry analysis showed that the melting and crystallization properties of DAGs prepared by ultrasonic pretreatment significantly differed from lard. FTIR spectra noted transesterification reaction from lard and GML with and without ultrasonic pretreatment would not change the structure of lard. However, thermogravimetric analysis proved that N-U-DAG, U-DAG, and P-U-DAG had lower oxidation stability than lard. The higher the content of DAG, the faster the oxidation speed.


Sujet(s)
Matières grasses alimentaires , Diglycéride , Diglycéride/composition chimique , Matières grasses alimentaires/analyse , Catalyse , Glycérol/composition chimique
13.
Anal Chem ; 95(11): 5109-5116, 2023 03 21.
Article de Anglais | MEDLINE | ID: mdl-36893116

RÉSUMÉ

The fast and selective separation method of intact monoacylglycerol (MG) and diacylglycerol (DG) isomers using chiral supercritical fluid chromatography-mass spectrometry (SFC-MS) was developed and employed to study lipase selectivity in the hydrolysis of triacylglycerols (TGs). The synthesis of 28 enantiomerically pure MG and DG isomers was performed in the first stage using the most commonly occurring fatty acids in biological samples such as palmitic, stearic, oleic, linoleic, linolenic, arachidonic, and docosahexaenoic acids. To develop the SFC separation method, different chromatographic conditions such as column chemistry, mobile phase composition and gradient, flow rate, backpressure, and temperature were carefully assessed. Our SFC-MS method used a chiral column based on a tris(3,5-dimethylphenylcarbamate) derivative of amylose and neat methanol as a mobile phase modifier, which provides baseline separation of all the tested enantiomers in 5 min. This method was used to evaluate hydrolysis selectivity of lipases from porcine pancreas (PPL) and Pseudomonas fluorescens (PFL) using nine TGs differing in acyl chain length (14-22 carbon atoms) and number of double bonds (0-6) and three DG regioisomer/enantiomers as hydrolysis intermediate products. PFL exhibited preference of the fatty acyl hydrolysis from the sn-1 position of TG more pronounced for the substrates with long polyunsaturated acyls, while PPL did not show considerable stereoselectivity to TGs. Conversely, PPL preferred hydrolysis from the sn-1 position of prochiral sn-1,3-DG regioisomer, whereas PFL exhibited no preference. Both lipases showed selectivity for the hydrolysis of outer positions of DG enantiomers. The results show complex reaction kinetics of lipase-catalyzed hydrolysis given by different stereoselectivities for substrates.


Sujet(s)
Chromatographie en phase supercritique , Triacylglycerol lipase , Animaux , Suidae , Triglycéride/analyse , Triacylglycerol lipase/composition chimique , Hydrolyse , Diglycéride/composition chimique , Monoglycérides , Spectrométrie de masse/méthodes , Stéréoisomérie , Catalyse
14.
J Sci Food Agric ; 103(1): 108-117, 2023 Jan 15.
Article de Anglais | MEDLINE | ID: mdl-35810339

RÉSUMÉ

BACKGROUND: Diacylglycerol (DAG)-enriched oil has been attracting attention because of its nutritional benefits and biological functions, although the composition of its various free fatty acids (FFAs) and an unclear relationship between substrate and yield make it difficult to be identified and qualified with respect to its production. In the present study, linoleic acid-enriched diacylglycerol (LA-DAG) was synthesized and enriched from Camellia oil by the esterification process using the combi-lipase Lipozyme TL IM/RM IM system. RESULTS: The relationship between FFA composition and DAG species productivity was revealed. The results showed that heterogeneous FFA with a major constituent (more than 50%) exhibited higher DAG productivity and inhibited triacylglycerol productivity compared to homogeneous constituents. Joint characterization by high-performance liquid chromatography-evaporative light scattering detection, gas chromatography-mass spectrometry and ultra-performance liquid chromatography-heated electrospray ionization-tandem mass spectrometry identified that DAG components contained dilinoleic acid acyl glyceride, linoleyl-oleyl glyceride and dioleic acid acyl glyceride in esterification products. Under the optimum conditions, 60.4% 1,3-DAG and 61.3% LA-DAG in the crude product at 1 h reaction were obtained, and further purified to 81.7% LA-DAG and 94.7% DAG via silica column chromatography. CONCLUSION: The present study provides a guideline for the identification of DAG species, as well as a structure-guided preparation method of DAG-enriched oils via the cost-effective combi-lipase. © 2022 Society of Chemical Industry.


Sujet(s)
Camellia , Diglycéride , Diglycéride/composition chimique , Acide linoléique , Triacylglycerol lipase/composition chimique , Huiles végétales/composition chimique , Glycérides , Acide gras libre
15.
J Oleo Sci ; 71(9): 1337-1348, 2022.
Article de Anglais | MEDLINE | ID: mdl-36047241

RÉSUMÉ

In this study, lipase A from Candida antarctica (CALA) was immobilized onto the macroporous resin NKA-9. Immobilization conditions (pH, time and CALA concentration) were studied, enzymatic activity and immobilization efficiency (IE) up to 968.89 U/g and 53.19% were respectively obtained under optimal conditions (immobilization pH 5.0, time 5 h and CALA concentration at 30 mg/mL). Then, the NKA-9 supported CALA (CALA@NKA-9) samples were used to catalyze glycerolysis in solvent-free system. With 0.25 g of the present CALA@NKA-9 (soybean oil 3.52 g and glycerol 0.184 g) and after 12 h reaction at 50 °C, diacylglycerols (DAG) content up to 64.37% and triacylglycerols (TAG) conversion at 83.33% were obtained. The relationship between temperature and TAG conversion was LnV 0 = 13.9310-6.4212/T for CALA@NKA-9. Meanwhile, the activation energy (Ea) of CALA@NKA-9 was calculated to be 53.39 kJ/mol. In addition, reusability in the glycerolysis reaction was also evaluated, and 57.82% of the initial glycerolysis activity was retained after 9 consecutive applications. Furthermore, the CALA@NKA-9 was also used to catalyze the esterification (esterification of fatty acids with glycerol), however, the present CALA@NKA-9 cannot initiate the esterification. Therefore, the present CALA@NKA-9 is shown to be potential for DAG production through glycerolysis reaction.


Sujet(s)
Enzymes immobilisées , Triacylglycerol lipase , Basidiomycota , Diglycéride/composition chimique , Enzymes immobilisées/composition chimique , Estérification , Protéines fongiques/composition chimique , Glycérol , Triacylglycerol lipase/composition chimique , Triglycéride
16.
J Phys Chem B ; 126(37): 7172-7183, 2022 09 22.
Article de Anglais | MEDLINE | ID: mdl-36041230

RÉSUMÉ

Diacylglycerol kinases (DGKs) are important enzymes in molecular membrane biology, as they can lower the concentration of diacylglycerol through phosphorylation while at the same time producing phosphatidic acid. Dysfunction of DGK is linked with multiple diseases including cancer and autoimmune disorders. Currently, the high-resolution structures have not been determined for any of the 10 human DGK paralogs, which has made it difficult to gain a more complete understanding of the enzyme's mechanism of action and regulation. In the present study, we have taken advantage of the significant developments in protein structural prediction technology by artificial intelligence (i.e., Alphafold 2.0), to conduct a comprehensive investigation on the properties of all 10 human DGK paralogs. Structural alignment of the predictions reveals that the C1, catalytic, and accessory domains are conserved in their spatial arrangement relative to each other, across all paralogs. This suggests a critical role played by this domain architecture in DGK function. Moreover, docking studies corroborate the existence of a conserved ATP-binding site between the catalytic and accessory domains. Interestingly, the ATP bound to the interdomain cleft was also found to be in proximity of the conserved glycine-rich motif, which in protein kinases has been suggested to function in ATP binding. Lastly, the spatial arrangement of DGK, with respect to the membrane, reveals that most paralogs possess a more energetically favorable interaction with curved membranes. In conclusion, AlphaFold predictions of human DGKs provide novel insights into the enzyme's structural and functional properties while also paving the way for future experimentation.


Sujet(s)
Diacylglycérol kinase , Diglycéride , Adénosine triphosphate , Intelligence artificielle , Diacylglycérol kinase/composition chimique , Diacylglycérol kinase/métabolisme , Diglycéride/composition chimique , Glycine , Humains , Acides phosphatidiques/composition chimique , Acides phosphatidiques/métabolisme , Protein kinases
17.
ACS Chem Biol ; 17(9): 2495-2506, 2022 09 16.
Article de Anglais | MEDLINE | ID: mdl-35767833

RÉSUMÉ

Diacylglycerol kinase ε (DGKε), an enzyme of the phosphatidylinositol (PI) cycle, bears a highly conserved hydrophobic N-terminal segment, which was proposed to anchor the enzyme into the membrane. However, the importance of this segment to the DGKε function remains to be determined. To address this question, it is here reported an in silico and in vitro combined research strategy. Capitalizing on the AlphaFold 2.0 predicted structure of human DGKε, it is shown that its hydrophobic N-terminal segment anchors it into the membrane via a transmembrane α-helix. Coarse-grained based elastic network model studies showed that a conformational change in the hydrophobic N-terminal segment determines the proximity between the active site of DGKε and the membrane-water interface, likely regulating its kinase activity. In vitro studies with a purified DGKε construct lacking the hydrophobic N-terminal segment (His-SUMO*-Δ50-DGKε) corroborated the role of the N-terminus in regulating DGKε enzymatic properties. The comparison between the enzymatic properties of DGKε and His-SUMO*-Δ50-DGKε showed that the conserved N-terminal segment markedly inhibits the enzyme activity and its sensitivity to membrane intrinsic negative curvature, while also playing a role in the modulation of the enzyme by phosphatidylserine. On the other hand, this segment did not strongly affect its diacylglycerol acyl chain specificity, the modulation of the enzyme by membrane morphological changes, or the activation by phosphatidic acid-rich lipid domains. Hence, these results suggest that the conservation of the hydrophobic N-terminal segment of DGKε throughout evolution guaranteed not only membrane anchorage but also an efficient and elegant manner to regulate the rate of the PI cycle.


Sujet(s)
Diacylglycérol kinase , Diglycéride , Diacylglycérol kinase/composition chimique , Diglycéride/composition chimique , Humains , Phosphatidyl inositols , Phosphatidylsérine , Eau
18.
Nat Commun ; 13(1): 2695, 2022 05 16.
Article de Anglais | MEDLINE | ID: mdl-35577811

RÉSUMÉ

Diacylglycerol (DAG) is a versatile lipid whose 1,2-sn-stereoisomer serves both as second messenger in signal transduction pathways that control vital cellular processes, and as metabolic precursor for downstream signaling lipids such as phosphatidic acid. Effector proteins translocate to available DAG pools in the membranes by using conserved homology 1 (C1) domains as DAG-sensing modules. Yet, how C1 domains recognize and capture DAG in the complex environment of a biological membrane has remained unresolved for the 40 years since the discovery of Protein Kinase C (PKC) as the first member of the DAG effector cohort. Herein, we report the high-resolution crystal structures of a C1 domain (C1B from PKCδ) complexed to DAG and to each of four potent PKC agonists that produce different biological readouts and that command intense therapeutic interest. This structural information details the mechanisms of stereospecific recognition of DAG by the C1 domains, the functional properties of the lipid-binding site, and the identities of the key residues required for the recognition and capture of DAG and exogenous agonists. Moreover, the structures of the five C1 domain complexes provide the high-resolution guides for the design of agents that modulate the activities of DAG effector proteins.


Sujet(s)
Diglycéride , Protéine kinase C , Animaux , Membrane cellulaire/métabolisme , Diglycéride/composition chimique , Liaison aux protéines , Protéine kinase C/composition chimique , Protéine kinase C/métabolisme , Structure tertiaire des protéines , Rats
19.
Food Chem ; 386: 132776, 2022 Aug 30.
Article de Anglais | MEDLINE | ID: mdl-35509162

RÉSUMÉ

Four types of pure lipid, namely lauric acid (LA), glycerol monolaurate (MAG), diglycerol laurate (DAG) and triglyceride laurate (TAG) were used to prepare oleofoams. The relationship between crystal profiles and their performance in oleofoams was established. DAG formed small needle-like crystals while MAG formed large flake-like crystals in oleogels, and crystal shells around air bubbles were observed in LA-, MAG- and DAG-based oleofoams. LA and DAG displayed higher over-run whereas DAG-stabilised foam possessed smaller bubbles and higher physical stability due to the presence of small ß and ß' crystals. Upon heating, DAG and TAG-based foams showed varying extents of oil drainage indicating the crystals were distributed in a different manner. Therefore, DAG was shown to be an excellent gelator in the fabrication of ultra-stable oleofoams. This work extends the lipid varieties with nutritional features and allows a better understanding on the stabilization mechanisms of lauric acid lipids in oleofoams.


Sujet(s)
Esters , Glycérol , Diglycéride/composition chimique , Laurate , Acides lauriques
20.
Food Chem ; 391: 133201, 2022 Oct 15.
Article de Anglais | MEDLINE | ID: mdl-35609461

RÉSUMÉ

This study developed an alpha-linolenic acid (ALA) supplement with emulsion form using ALA-rich diacylglycerol (ALA-DAG) and ALA-DAG stearin (DAG-SF) as a new source of ALA and emulsifier. Stable, commercial surfactant-free W/O emulsions with 90 wt% oil phase (including DAG-SF and ALA-DAG with 10:90 - 20:80 wt ratio) was fabricated. Microstructure and Raman spectra revealed that the compact crystal networks and high amounts of solid acyl chains were responsible for high emulsion stability. These emulsions exhibited good potential in improving the ALA nutritional status (with ALA release level of 60.49% - 62.98%). Furthermore, the emulsifier-to-oil ratio greatly impacted the emulsion texture (solid-like or liquid-like) and emulsions showed great oxidation stability (2.80 - 3.09 meq/kg lipid of peroxide value at 6th week). The tunable texture and high oxidation stability make this emulsion system useful for a wide range of food products. This developed emulsion system could provide valuable information for other important fatty acids supplement.


Sujet(s)
Diglycéride , Acide alpha-linolénique , Digestion , Diglycéride/composition chimique , Émulsifiants , Émulsions/composition chimique , Eau/composition chimique
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