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1.
Open Life Sci ; 19(1): 20220946, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39329022

RESUMO

This study investigates the osmotic dehydration process of watermelon rind using a solution composed of honey and sucrose. The impact of the ratio of rind-to-solution and temperature on the process is illustrated. Pre-treatments such as blanching, microwaves, and ultrasonication were utilized. Ultrasonication reduces the time needed for osmosis in a sample, resulting in increased fluid loss and solute uptake; therefore, it was selected as the method to investigate the kinetics and modelling of mass transfer. The effective diffusivities for water loss (ranging from 3.02 × 10-5 to 4.21 × 10-4 m2 s-1) and solid gain (ranging from 1.94 × 10-6 to 3.21 × 10-6 m2 s-1) were shown to increase with process variables such as temperature and the rind-to-solution ratio. The activation energy decreased as the process temperature increased, ranging from 3.723 to 0.928 kJ mol-1 for water loss and from 1.733 to 0.903 kJ mol-1 for solid gain, respectively. The sample treated with microwaves exhibited the maximum dehydration coefficient, rendering it appropriate for producing dehydrated products. Five empirical models were utilized, with the power law model (R 2 = 0.983) and the Magee model (R 2 = 0.950) being the most suitable for water loss data and solid gain, respectively.

2.
Heliyon ; 10(17): e36964, 2024 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-39286177

RESUMO

Baby corn, characterized by its high water activity and elevated respiration rate, poses a formidable obstacle to prolonged storage under standard ambient conditions and necessitates specialized treatments for transportation to distant locations. One of the primary postharvest challenges associated with baby corn is the occurrence of brown pigment formation because of enzymatic browning at the apex of its immature ovules, cut surfaces, and silk attached to the young ears. The present study was undertaken to investigate the effect of different blanching treatments on peroxidase inactivation, physicochemical properties, and functional properties of baby corn. The treatments applied were hot water blanching (HWB) at temperatures ranging from 70°C to 90 °C for 30-240 s, steam blanching (SB) for 30-240 s, and microwave blanching (MWB) at power levels of 360 W-900 W for 30-300 s. Results indicated that 90 % peroxidase enzyme inactivation occurred under different methods as 90 °C for 60 s for HWB, 100 °C for 60 s for SB, and 540 W for 30 s for MWB. These blanching methods have shown significant effects on the properties under investigation. MWB demonstrated the highest retention of ascorbic acid (94.15 %) and minimal color changes (ΔE = 5.72) in comparison to hot water and steam blanching. Similarly, the result for total flavonoid content for 540 W, 90 °C and 100 °C for 30, 60, and 60 s were found to be 3.01,1.99 and 2.10 mg QE/100g, phenols 48.98, 47.99 and 48.03 mg GAE/100g and DPPH (%) 42.55, 34.20 and 37.08 % respectively. The findings suggest that microwave blanching of baby corn at 540 W for 30 s holds promise to inactivate the peroxidase enzyme with better retention of physicochemical and functional properties.

3.
Proc Natl Acad Sci U S A ; 121(33): e2401133121, 2024 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-39102538

RESUMO

The hierarchic assembly of fibrillar collagen into an extensive and ordered supramolecular protein fibril is critical for extracellular matrix function and tissue mechanics. Despite decades of study, we still know very little about the complex process of fibrillogenesis, particularly at the earliest stages where observation of rapidly forming, nanoscale intermediates challenges the spatial and temporal resolution of most existing microscopy methods. Using video rate scanning atomic force microscopy (VRS-AFM), we can observe details of the first few minutes of collagen fibril formation and growth on a mica surface in solution. A defining feature of fibrillar collagens is a 67-nm periodic banding along the fibril driven by the organized assembly of individual monomers over multiple length scales. VRS-AFM videos show the concurrent growth and maturation of small fibrils from an initial uniform height to structures that display the canonical banding within seconds. Fibrils grow in a primarily unidirectional manner, with frayed ends of the growing tip latching onto adjacent fibrils. We find that, even at extremely early time points, remodeling of growing fibrils proceeds through bird-caging intermediates and propose that these dynamics may provide a pathway to mature hierarchic assembly. VRS-AFM provides a unique glimpse into the early emergence of banding and pathways for remodeling of the supramolecular assembly of collagen during the inception of fibrillogenesis.


Assuntos
Microscopia de Força Atômica , Imagem Individual de Molécula , Microscopia de Força Atômica/métodos , Imagem Individual de Molécula/métodos , Animais , Matriz Extracelular/metabolismo , Colágenos Fibrilares/metabolismo , Colágenos Fibrilares/química , Colágeno/metabolismo , Colágeno/química , Silicatos de Alumínio
4.
J Texture Stud ; 55(4): e12861, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-39138121

RESUMO

This study offers a comprehensive review of current developments regarding the utilization of diverse hydrocolloids in formulating fruit fillings across different fruit types, their impact on textural attributes, rheological properties, thermal stability, syneresis, and nutritional advantages of fillings and optimization of its characteristics to align with consumer preferences. The review also focuses on the various factors influencing fruit fillings, including the selection of fruits, processing methodologies, the inherent nature and concentration of hydrocolloids, and their synergistic interactions. In depth, scientific work on the impact of the parameters such as pH, total soluble solids, and sugar content within the fruit fillings was also discussed. Additionally, this article focuses on the utilization of the diverse fruit fillings developed by using hydrocolloids in bakery products including pastry, tartlet, muffins, cookies, and so forth. The review establishes that hydrocolloids offer a spectrum of techno-functional attributes conducive to strengthening both the structural and thermal stability of fruit fillings, consequently extending their shelf life. It further establishes that incorporating of hydrocolloids facilitates the development of healthier food products by mitigating the necessity of excessive sugar or various other less favorable ingredients. The incorporation of fruit fillings in bakery products significantly increases the value proposition of these baked goods, contributing to their overall enhancement of quality and sensory value.


Assuntos
Coloides , Manipulação de Alimentos , Frutas , Frutas/química , Manipulação de Alimentos/métodos , Reologia , Humanos , Valor Nutritivo
5.
Food Chem X ; 23: 101527, 2024 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-38974201

RESUMO

Green leafy vegetables, especially microgreens are gaining popularity due to their high nutritional profiles, rich phytochemical content, and intense flavors. This review explores the growing commercial market for microgreens, especially in upscale dining and premium grocery outlets, highlighting consumer perceptions and their effect on market dynamics. Apart from these, the effect of modern agricultural methods that maximize the growth of microgreens is also examined. The value is anticipated to increase significantly, according to market predictions, from $1.7 billion in 2022 to $2.61 billion by 2029. Positive consumer views on microgreens health benefits drive this growth, although challenges such as varying levels of consumer awareness and income disparities affect sales. The review underscores the need for targeted research and strategic initiatives to enhance consumer understanding and improve cultivation methods to support market expansion in upcoming years.

6.
Food Chem X ; 23: 101554, 2024 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-39036476

RESUMO

Corn silk (Zea mays L.), an abundant agricultural waste, contains various bioactive compounds that exhibit promising health benefits. The current study focuses on development and optimization of corn silk-based instant mix using response surface methodology. The optimized product, with 14.66% corn silk, 10% sugar and 0.22% xanthan gum in a skim milk powder base, scored 0.925 desirability. The physico-chemical and sensory parameters of optimized mix closely aligned with expected values. The instant mix packaged in metallised polyester yielded superior preservation of quality indicators over 120 days compared to low-density polyethylene (LDPE) and high-density polyethylene (HDPE). The microbial load in corn silk instant mix was observed across packaging materials and highlighting hydroxyl methyl furfural (HMF) as the primary predictor of product stability, the study calculated a 94.95 days half-life at 10 °C. Corn silk's rich bioactive compound supports its integration into nutraceuticals and instant mixes, mitigating food waste while enhancing nutritional value. Novelty statement. In this study, corn silk powder was utilized for the development of the instant mix. This innovative approach transforms corn silk, typically discarded as agricultural waste, into a commercially sustainable product that delivers the nutrients of corn silk to a broader population. Despite fresh corn silk being a perishable commodity, it has very low storage shelf life. The developed instant mix effectively preserves its nutritional value for up to six months, offering a sustainable and nutritious option for consumers.

8.
Sci Rep ; 14(1): 1647, 2024 01 18.
Artigo em Inglês | MEDLINE | ID: mdl-38238415

RESUMO

The present research study aimed to examine three different herb extract's effects on the discoloration rate of fresh-cut pear slices using an image analysis technique. Pear slices were sprayed and dip-coated with Ocimum basilicum, Origanum vulgare, and Camellia sinensis (0.1 g/ml) extract solution. During 15 days storage period with three days intervals, all sprayed/dip-coated pear slices were analyzed for the quality attribute (TA) and color parameters notably a*, b*, hue angle (H*), lightness (L*), and total color change (ΔE). Further, order kinetic models were used to observe the color changes and to predict the shelf-life. The results obtained showed that the applicability of image analysis helped to predict the discoloration rate, and it was better fitted to the first-order (FO) kinetic model (R2 ranging from 0.87 to 0.99). Based on the kinetic model, color features ΔE and L* was used to predict the shelf-life as they had high regression coefficient values. Thus, the findings obtained from the kinetic study demonstrated Camellia sinensis (assamica) extract spray-coated pear slices reported approximately 28.63- and 27.95-days shelf-stability without much discoloration compared with all other types of surface coating.


Assuntos
Pyrus , Cinética , Extratos Vegetais/farmacologia
9.
Matrix Biol Plus ; 21: 100139, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38186852

RESUMO

Collagens are the most abundant structural proteins in the extracellular matrix of animals and play crucial roles in maintaining the structural integrity and mechanical properties of tissues and organs while mediating important biological processes. Fibrillar collagens have a unique triple helix structure with a characteristic repeating sequence of (Gly-X-Y)n. Variations within the repetitive sequence can cause misfolding of the triple helix, resulting in heritable connective tissue disorders. The most common variations are single-point missense mutations that lead to the substitution of a glycine residue with a bulkier amino acid (Gly â†’ X). In this review, we will first discuss the importance of collagen's triple helix structure and how single Gly substitutions can impact its folding, structure, secretion, assembly into higher-order structures, and biological functions. We will review the role of "designer collagens," i.e., synthetic collagen-mimetic peptides and recombinant bacterial collagen as model systems to include Gly â†’ X substitutions observed in collagen disorders and investigate their impact on structure and function utilizing in vitro studies. Lastly, we will explore how computational modeling of collagen peptides, especially molecular and steered molecular dynamics, has been instrumental in probing the effects of Gly substitutions on structure, receptor binding, and mechanical stability across multiple length scales.

10.
Proteins ; 92(1): 52-59, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37596815

RESUMO

The core metabolic reactions of life drive electrons through a class of redox protein enzymes, the oxidoreductases. The energetics of electron flow is determined by the redox potentials of organic and inorganic cofactors as tuned by the protein environment. Understanding how protein structure affects oxidation-reduction energetics is crucial for studying metabolism, creating bioelectronic systems, and tracing the history of biological energy utilization on Earth. We constructed ProtReDox (https://protein-redox-potential.web.app), a manually curated database of experimentally determined redox potentials. With over 500 measurements, we can begin to identify how proteins modulate oxidation-reduction energetics across the tree of life. By mapping redox potentials onto networks of oxidoreductase fold evolution, we can infer the evolution of electron transfer energetics over deep time. ProtReDox is designed to include user-contributed submissions with the intention of making it a valuable resource for researchers in this field.


Assuntos
Oxirredutases , Oxirredutases/química , Oxirredução , Transporte de Elétrons
11.
Food Sci Technol Int ; : 10820132231219715, 2023 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-38099822

RESUMO

The research aims to enhance the characteristics of honey by incorporating xanthan gum (XG) and guar gum (GG) at various concentrations (0.5-2.0% w/w) and preparing a honey gel matrix (HGM) through high-shear homogenization. This approach serves as a substitute for fat-based filling materials commonly used in bakery products. The study encompassed an investigation of the rheological characteristics (steady and dynamic), total phenolic content (TPC), antioxidant activity, and baking stability of the HGMs. The concentration of the gums used significantly influenced the transformation of honey into the HGM and its stability. Notably, the XG-HGM demonstrated greater shear thinning behavior and higher consistency compared to the GG-HGM. Herschel Bulkley and power law models were found to be the best-fitted models for XG-HGM and GG-HGM, respectively. Furthermore, both XG-HGM and GG-HGM exhibited a higher viscous component (G″) than an elastic component (G') at low concentrations, up to 1% (w/w) for XG-HGM and 1.5% (w/w) for GG-HGM; however, this behavior reversed beyond those concentrations (G' > G″). The XG-HGM exhibited lower temperature sensitivity compared to GG-HGM, indicating better stability under varying heat conditions. Moreover, both TPC and antioxidant activity decreased with increasing concentrations of both gums. The XG-HGM achieved the highest baking stability index, reaching 95.23% at a 2% concentration. This modified HGM formulated with XG demonstrated superior consistency, color retention, and exceptional baking stability, making it a promising candidate for application as a filling material in the bakery sector. Its improved stability and quality can facilitate the development of a wide range of baking products in the food industry.

12.
ACS Omega ; 8(32): 29558-29567, 2023 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-37608870

RESUMO

Due to the significant increase in global pollution and a corresponding decrease in agricultural land, there is a growing demand for sustainable modes of modern agriculture that can provide nutritious food. In this regard, microgreens are an excellent option as they are loaded with nutrients and can be grown in controlled environments using various vertical farming approaches. Microgreens are salad crops that mature within 15-20 days, and they have tender leaves with an abundant nutritive value. Therefore, this study aims to explore the physicochemical, techno-functional, functional, thermal, and morphological characteristics of four botanical varieties of microgreens, including carrot (Daucus carota), spinach (Spinacia oleracea), bathua (Chenopodium album), and Bengal gram (Cicer arietinum), which are known for their exceptional nutritional benefits. Among the four botanical varieties of microgreens studied, bathua microgreens demonstrated the highest protein content (3.40%), water holding capacity (1.58 g/g), emulsion activity (56.37%), and emulsion stability (53.72%). On the other hand, Bengal gram microgreens had the highest total phenolic content (32.2 mg GAE/g), total flavonoid content (7.57 mg QE/100 g), and DPPH activity (90.60%). Fourier transform infrared spectroscopy analysis of all microgreens revealed the presence of alkanes, amines, and alcohols. Moreover, X-ray diffraction analysis indicated low crystallinity and high amorphousness in the microgreens. Particle size analysis showed that the median, modal, and mean sizes of the microgreens ranged from 110.327 to 952.393, 331.06 to 857.773, and 97.567 to 406.037 µm, respectively. As per the observations of the results, specific types of microgreens can be utilized as an ingredient in food processing industry, including bakery, confectionery, and more, making them a promising nutritive additive for consumers. This study sheds light on various food-based analytical parameters and offers a foundation for future research to fully harness the potential of microgreens as a novel and sustainable food source, benefiting both the industry and consumers alike.

13.
3 Biotech ; 13(7): 246, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37361240

RESUMO

Cancer is a broad collection of diseases that can begin in almost any organ or tissue of the body. Corn silk is the hair-like stigmata of female maize flowers which is generally discarded as waste from maize cultivation. The current study targets the anti-cancer potential of corn silk and its bioactive compounds namely, polyphenols, flavonoids, and sterols. The polyphenols and flavonoids like quercetin, rutin, apigenin and beta-sitosterol are a range of compounds from corn silk which were investigated for their anticancer effect. Corn silk showed apoptotic and antiproliferative effects in cancer cells through different signalling pathways, essentially the serine/threonine kinases (Akt)/lipid kinases (PI3Ks) pathway. The study revealed that corn silk compounds target immune cell responses, induce cell cytotoxicity, and upregulate the expression of proapoptotic genes p53, p21, caspase 9, and caspase 3 in certain cancer cell lines including HeLa cervical cancer cells, MCF-7 breast cancer cells, PANC-02 pancreatic cancer cells and Caco-2 colon cancer cells. Flavonoids derived from corn silk enhance T cell mediated immune response and decrease inflammatory factors. Corn silk bioactive compounds were found to reduce the side effects of cancer therapy. Antioxidants of corn silk, quercetin and rutin help in reducing the nephrotoxicity of chemotherapeutic drugs. The study also suggests that corn silk has anti-cancerous potential as it targets tumour suppression and inhibits metastasis A dose of 500 mg/kg body weight of corn silk has been found safe for human consumption. Corn silk extract can be used as a preventive or therapeutic step to cure cancer. The anti-cancer property, mechanism and role of corn silk in controlling cancer-related side effects have been critically reviewed providing new scope for the use of corn silk in cancer therapy.

14.
J Food Sci Technol ; 60(6): 1695-1710, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37187994

RESUMO

Management of glycaemic response is perhaps the most critical part of antidiabetic therapy. Hypoglycaemia is an avoidable complication caused by conventional drugs used in the treatment of diabetes. It triggers commonly during the intensification of anti-hyperglycemic therapy used to render glycemic control in diabetic patients. The commercial oral hypoglycaemic drugs, insulin, herbal medicines and plant extracts are therefore used as a part of the treatment of diabetes. The demand for treating diabetes, through herbal and plant resources is due to their lesser adverse reactions and better phytochemical benefits. Corn silk has been shown to have anti-allergic, anti-inflammatory, and anti-hypertensive effects when extracted in various solvents. Corn silk has medicinal characteristics and has long been used as a traditional medicine in many nations, although the mechanism of action is unknown. The hypoglycaemic effects of corn silk are investigated in this review. The phytochemical components present in corn silk-like flavonoids, phenolics, terpenoids, tannins, sterols, and alkaloids are phytochemical components that have hypoglycemic activity and a mechanism for lowering blood glucose levels. There is a lack of a homogenized database on the hypoglycemic properties of corn silk thus the present review attempts to critically analyse it and provide specific recommendations of its doses.

15.
PLoS One ; 18(5): e0285864, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37196046

RESUMO

Streptococcus pyogenes-derived recombinant bacterial collagen-like proteins (CLPs) are emerging as a potential biomaterial for biomedical research and applications. Bacterial CLPs form stable triple helices and lack specific interactions with human cell surface receptors, thus enabling the design of novel biomaterials with specific functional attributes. Bacterial collagens have been instrumental in understanding collagen structure and function in normal and pathological conditions. These proteins can be readily produced in E. coli, purified using affinity chromatography, and subsequently isolated after cleavage of the affinity tag. Trypsin is a widely used protease during this purification step since the triple helix structure is resistant to trypsin digestion. However, the introduction of Gly→X mutations or natural interruptions within CLPs can perturb the triple helix structure, making them susceptible to trypsin digestion. Consequently, removing the affinity tag and isolating collagen-like (CL) domains containing mutations is impossible without degradation of the product. We present an alternative method to isolate CL domains containing Gly→X mutations utilizing a TEV protease cleavage site. Protein expression and purification conditions were optimized for designed protein constructs to achieve high yield and purity. Enzymatic digestion assays demonstrated that CL domains from wild-type CLPs could be isolated by digestion with either trypsin or TEV protease. In contrast, CLPs containing Gly→Arg mutations are readily digested by trypsin while digestion with TEV protease cleaved the His6-tag, enabling the isolation of mutant CL domains. The developed method can be adapted to CLPs containing various new biological sequences to develop multifunctional biomaterials for tissue engineering applications.


Assuntos
Colágeno , Escherichia coli , Humanos , Escherichia coli/genética , Escherichia coli/metabolismo , Tripsina , Colágeno/metabolismo , Proteínas Recombinantes/genética , Proteínas de Bactérias/metabolismo , Materiais Biocompatíveis , Proteínas Recombinantes de Fusão
16.
Sci Adv ; 9(10): eabq1990, 2023 03 10.
Artigo em Inglês | MEDLINE | ID: mdl-36897954

RESUMO

Ancestral metabolic processes involve the reversible oxidation of molecular hydrogen by hydrogenase. Extant hydrogenase enzymes are complex, comprising hundreds of amino acids and multiple cofactors. We designed a 13-amino acid nickel-binding peptide capable of robustly producing molecular hydrogen from protons under a wide variety of conditions. The peptide forms a di-nickel cluster structurally analogous to a Ni-Fe cluster in [NiFe] hydrogenase and the Ni-Ni cluster in acetyl-CoA synthase, two ancient, extant proteins central to metabolism. These experimental results demonstrate that modern enzymes, despite their enormous complexity, likely evolved from simple peptide precursors on early Earth.


Assuntos
Hidrogenase , Níquel , Níquel/química , Níquel/metabolismo , Hidrogenase/química , Prótons , Hidrogênio/química , Peptídeos
17.
Nat Commun ; 13(1): 6761, 2022 11 09.
Artigo em Inglês | MEDLINE | ID: mdl-36351904

RESUMO

Collagens are the most abundant proteins of the extracellular matrix, and the hierarchical folding and supramolecular assembly of collagens into banded fibers is essential for mediating cell-matrix interactions and tissue mechanics. Collagen extracted from animal tissues is a valuable commodity, but suffers from safety and purity issues, limiting its biomaterials applications. Synthetic collagen biomaterials could address these issues, but their construction requires molecular-level control of folding and supramolecular assembly into ordered banded fibers, comparable to those of natural collagens. Here, we show an innovative class of banded fiber-forming synthetic collagens that recapitulate the morphology and some biological properties of natural collagens. The synthetic collagens comprise a functional-driver module that is flanked by adhesive modules that effectively promote their supramolecular assembly. Multiscale simulations support a plausible molecular-level mechanism of supramolecular assembly, allowing precise design of banded fiber morphology. We also experimentally demonstrate that synthetic fibers stimulate osteoblast differentiation at levels comparable to natural collagen. This work thus deepens understanding of collagen biology and disease by providing a ready source of safe, functional biomaterials that bridge the current gap between the simplicity of peptide biophysical models and the complexity of in vivo animal systems.


Assuntos
Materiais Biocompatíveis , Colágeno , Animais , Materiais Biocompatíveis/química , Colágeno/metabolismo , Matriz Extracelular/metabolismo , Peptídeos
18.
Orig Life Evol Biosph ; 52(4): 263-275, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36383289

RESUMO

Protein coordinated iron-sulfur clusters drive electron flow within metabolic pathways for organisms throughout the tree of life. It is not known how iron-sulfur clusters were first incorporated into proteins. Structural analogies to iron-sulfide minerals present on early Earth, suggest a connection in the evolution of both proteins and minerals. The availability of large protein and mineral crystallographic structure data sets, provides an opportunity to explore co-evolution of proteins and minerals on a large-scale using informatics approaches. However, quantitative comparisons are confounded by the infinite, repeating nature of the mineral lattice, in contrast to metal clusters in proteins, which are finite in size. We address this problem using the Niggli reduction to transform a mineral lattice to a finite, unique structure that when translated reproduces the crystal lattice. Protein and reduced mineral structures were represented as quotient graphs with the edges and nodes corresponding to bonds and atoms, respectively. We developed a graph theory-based method to calculate the maximum common connected edge subgraph (MCCES) between mineral and protein quotient graphs. MCCES can accommodate differences in structural volumes and easily allows additional chemical criteria to be considered when calculating similarity. To account for graph size differences, we use the Tversky similarity index. Using consistent criteria, we found little similarity between putative ancient iron-sulfur protein clusters and iron-sulfur mineral lattices, suggesting these metal sites are not as evolutionarily connected as once thought. We discuss possible evolutionary implications of these findings in addition to suggesting an alternative proxy, mineral surfaces, for better understanding the coevolution of the geosphere and biosphere.


Assuntos
Proteínas Ferro-Enxofre , Metaloproteínas , Minerais , Proteínas Ferro-Enxofre/química , Proteínas Ferro-Enxofre/metabolismo , Enxofre/química , Enxofre/metabolismo , Ferro/química
19.
Nat Chem ; 14(12): 1427-1435, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-36316409

RESUMO

Peptide materials have a wide array of functions, from tissue engineering and surface coatings to catalysis and sensing. Tuning the sequence of amino acids that comprise the peptide modulates peptide functionality, but a small increase in sequence length leads to a dramatic increase in the number of peptide candidates. Traditionally, peptide design is guided by human expertise and intuition and typically yields fewer than ten peptides per study, but these approaches are not easily scalable and are susceptible to human bias. Here we introduce a machine learning workflow-AI-expert-that combines Monte Carlo tree search and random forest with molecular dynamics simulations to develop a fully autonomous computational search engine to discover peptide sequences with high potential for self-assembly. We demonstrate the efficacy of the AI-expert to efficiently search large spaces of tripeptides and pentapeptides. The predictability of AI-expert performs on par or better than our human experts and suggests several non-intuitive sequences with high self-assembly propensity, outlining its potential to overcome human bias and accelerate peptide discovery.


Assuntos
Simulação de Dinâmica Molecular , Peptídeos , Humanos , Peptídeos/química , Aprendizado de Máquina , Hidrogéis/química , Aminoácidos
20.
Carbohydr Res ; 521: 108647, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36029635

RESUMO

Sucralose differs from sucrose only by virtue of having three Cl groups instead of OH groups. Its intriguing features include being noncaloric, noncariogenic, ∼600 times sweeter than sucrose, stable at high temperatures/acidic pH's, and void of disagreeable aftertastes. These properties are attractive as food additive, one of which is as hydrogel obtainable via the technique of molecular gelation using a sucralose-derived low-molecular weight gelator (LMWG). Such hydrogels are highly responsive to external stimuli like temperature, because the LMWGs self-assemble via non-covalent interactions and could thus be utilized in applications like control-release. We found that sucralose to be unreactive under lipase biocatalysis, unlike sucrose. Hence, the aim of this work was (i) to use computational simulations to further understand sucralose's lack of enzymatic reactivity and (ii) to synthesize the sucralose-based amphiphiles using conventional chemical synthesis and systematically study their tendency towards hydrogelation. Sucrose and sucralose were docked with a high-resolution atomic structure of lipase B from Candida antarctica, modeling the esterification transition state with an active site serine. In extended molecular dynamics simulations, sucrose remained in the active site due to multiple sugar-protein hydrogen bonds. The oxygen-to-chlorine substitutions in sucralose disrupted this hydrogen bonding network. Consistent with observed lack of enzymatic conversion, in multiple simulations, sucralose would rapidly dissociate from the active site. The sucralose-based LMWGs were subsequently synthesized using base-catalyzed conventional chemical synthesis. Three of the sucralose-based amphiphiles (SL-5, SL-6 and SL-7) proved to be successful hydrogelators. The gelators also showed the ability to gel selected beverages. The LMWGs gelled quantities of water and beverage up to 71 and 55 times their weight, respectively, and remain thermally stable up to 144 °C.


Assuntos
Hidrogéis , Lipase , Biocatálise , Cloro , Esterificação , Aditivos Alimentares , Hidrogéis/química , Oxigênio , Serina , Sacarose/análogos & derivados , Sacarose/química , Água
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