Chemical Composition Of Protein Research Articles

Combining Chemical Protein Synthesis and Random Nonstandard Peptides Integrated Discovery for Modulating Biological Processes.

ConspectusChemical manipulation of naturally occurring peptides offers a convenient route for generating analogs to screen against different therapeutic targets. However, the limited success of the conventional chemical libraries has urged chemical biologists to adopt alternative methods such as phage and mRNA displays and create libraries of a large number of variants for the screening and selection of novel peptides. Messenger RNA (mRNA) display provides great advantages in terms of the library size and the straightforward recovery of the selected polypeptide sequences. Importantly, the integration of the flexible in vitro translation (FIT) system with the mRNA display provides the basis of the random nonstandard peptides integrated discovery (RaPID) approach for the introduction of diverse nonstandard motifs, such as unnatural side chains and backbone modifications. This platform allows the discovery of functionalized peptides with tight binding against virtually any protein of interest (POI) and therefore shows great potential in the pharmaceutical industry. However, this method has been limited to targets generated by recombinant expression, excluding its applications to uniquely modified proteins, particularly those with post-translational modifications.Chemical protein synthesis allows a wide range of changes to the protein's chemical composition to be performed, including side chain and backbone modifications and access to post-translationally modified proteins, which are often inaccessible or difficult to achieve via recombinant expression methods. Notably, d-proteins can be prepared via chemical synthesis, which has been used in mirror image phase display for the discovery of nonproteolytic d-peptide binders.Combining chemical protein synthesis with the RaPID system allows the production of a library of trillions of cyclic peptides and subsequent selection for novel cyclic peptide binders targeting a uniquely modified protein to assist in studying its unexplored biology and possibly the discovery of new drug candidates.Interestingly, the small post-translational modifier protein ubiquitin (Ub), with its various polymeric forms, regulates directly or indirectly many biochemical processes, e.g., proteasomal degradation, DNA damage repair, cell cycle regulation, etc. In this Account, we discuss combining the RaPID approach against various synthetic Ub chains for selecting effective and specific macrocyclic peptide binders. This offers an advancement in modulating central Ub pathways and provides opportunities in drug discovery areas associated with Ub signaling. We highlight experimental approaches and conceptual adaptations required to design and modulate the activity of Lys48- and Lys63-linked Ub chains by macrocyclic peptides. We also present the applications of these approaches to shed light on related biological activities and ultimately their activity against cancer. Finally, we contemplate future developments still pending in this exciting multidisciplinary field.

Structural and emulsion stabilization comparison of four gelatins from two freshwater and two marine fish skins

This study analyzed the structural and emulsion stabilization properties of two freshwater and two marine fish skin gelatins: Chinese longsnout catfish skin gelatin (CLCSG), silver carp skin gelatin (SCSG), salmon skin gelatin (SSG), and Alaska pollack skin gelatin (APSG). Their gel strengths (Bloom values) were: 361 ± 1 (SCSG) > 253 ± 4 (CLCSG) > 69 ± 1 (SSG) > 36 ± 2 (APSG). Higher molecular weights and α/β subunit contents of gelatins might induce higher gel strengths. Both creaming and droplet stability were completely the same to the contents of imino acids, β-sheet percentages, and β-turn percentages, whereas they were completely the opposite to random coil percentages. The emulsion stabilization mechanisms involved an “fish skin source – protein chemical composition – protein secondary structure – protein functional properties – emulsion stability” route. This study provided useful knowledges for gelatin science and for the comprehensive utilization of aquatic by-products in gelatin industry.

Using Probiotic Bacteria for Soymilk Fermentation

Five probiotic bacterial strains (Lactobacillus plantarumATCC 14917,Lactobacillus caseiDSM 20011, Lactobacillus acidophilus ATCC20552, Lactococcus thermophilus DSM 20259,and Bifidobacterium longum B41409) were used as monoculture, and combined with them as co-cultures for the fermentation of soymilk. The total number is 20 co-cultures, separated similarly into two parts, the first half of each co-culture consisted of two strains, and the second half of each co-culture consists of three strains. The findings revealed that these cultures were capable of fermenting soymilk at only 8 h with a pH drop of between 4.42 and 4.89. Among 25 cultures, eight cultures (3 monoculture of L. plantarumATCC 14917 (C1),Lc. thermophilusDSM 20259 (C4), and B. longum B41409 (C5) and co-cultures of two strains L. plantarum ATCC 14917+ Lc. thermophiles DSM 20259 (C8) and of three strains L. plantarum ATCC 14917 + Lc. thermophilus DSM 20259 + B. longum B41409 (C18), L. plantarum ATCC 14917+ L. caseiDSM 20011+ Lc. thermophilus DSM 20259 (C19), L. caseiDSM 20011+ L. acidophilus ATCC20552+ Lc. thermophilus DSM 20259 (C22), and L. acidophilus ATCC20552+ Lc. thermophilus DSM 20259 + B. longum B41409 (C25)) which recorded the greatest significant viability of bacterial cells, titratable acidity, total organic acids (lactic, acetic, and propionic acids) contented, and pH in fermented soymilk ranged from 9.26 to 9.98 Log CFU/mL, 3.06 to 3.32 %, 19.90 to 18.40 g/L (lactic acid), 13.30 to 12.30 g/L (acetic acid), and 16.35 to15.00 g/L (propionic acid), and 4.38 to 4.62. The soy yogurt produced from the selected fermentation of soymilk was more preferred in the chemical composition of protein, carbohydrate, and fat contents than non-fermented soymilk.So the results show that the integrative use of probiotics may achieve the nutritional value of soymilk after fermentation had been improved by probiotic strains, therefore, making it a more health-beneficial functional food.

VCS-Diamante: cultivar de sorgo blanco para el estado de Sinaloa

La nueva variedad de sorgo VCS Diamante fue desarrollado en el Campo Experimental Valle de Culiacán (CEVACU) del INIFAP y registrada con el número SOG-282-231117 y título de obtentor número 1892, en el Catálogo Nacional de Variedades Vegetales (CNVV) del SINCS de México. Esta variedad se adapta a las áreas productoras de sorgo para el estado de Sinaloa. VCS Diamante es una variedad de ciclo vegetativo intermedio, de grano crema o ámbar, se recomienda para condiciones de riego y temporal. El rendimiento promedio de la variedad es de 3 310 kg ha-1 de grano y 27 105 kg ha-1 de forraje verde, superior en promedio 15.4 y 25.47% respectivamente, al rendimiento de híbridos comerciales, que se cultivan en la región bajo las mismas condiciones en temporal. VCS-Diamante tiene al igual que los híbridos comerciales aceptable calidad bromatológica en el forraje, con 6.21% de proteína y 78.66% de digestibilidad. Es tolerante a enfermedades que se presentan en la región, como son: ergot (Claviceps africana), antracnosis (Colletotrichum graminicola), tizón de la panoja (Fusarium moniliforme) y pudrición carbonosa del tallo (Macrophomina phaseolina), presenta tolerancia al pulgón amarillo del sorgo (Melanaphis sacchari Zehntner). VCS-Diamante presenta un tamaño de grano de 4.61, 4.35 y 2.8 mm, de largo, ancho y grosor y una composición química de proteínas, lípidos, cenizas y carbohidratos de 14.95, 3.93, 2.04 y 79.08%, respectivamente.

Improvement of the Quality of Surimi Products with Overdrying Potato Starches

This study investigated the effect of overdrying potato starches on surimi products. The chemical composition of protein and chemical interactions, gel solubility, and protein conformation of the mixture of surimi gel protein, respectively, with 8% native potato starch and with 8% overdrying potato starch were investigated. The results show that the starch increased the insoluble protein content. In terms of the chemical interactions, the overdrying potato starch increased the amount of hydrogen bond and nondisulfide covalent bond and decreased the amount of ionic bond, which might stabilize the network structure of protein gel. The analysis of Raman Spectroscopy shows that more α-helices turn into random coin structure after the starch was added, which is conducive to higher strength and a better water retention ability of the surimi product.

Relation between selected nutrients in the chicken meat depending on phytogenic feed additives

The aim of study was to evaluate the relation between selected nutrients in the breast and thigh muscles after the application of different phytogenic additives in the diet of broiler chickens and between same indicators of meat disregarding additive and parts of carcass, from which muscles originate. We realized an in vivo experiment on the Zámostie Company poultry test station with deep litter breeding system. The experiment included 100 pcs of one-day-old hybrid chickens Cobb 500 divided into 2 groups (n = 50): the 1st experimental group with an application of feed additive from chestnut tree and lemon fruit extracts and the 2nd experimental group with an application of feed additive from citrus fruits extract. We used a cereal and soybean basal diet and we divided the fattening period into four phases: starter (1 - 10 days), grower I (11 - 20 days), grower II (21 - 28 days) and finisher (29 - 42 days). We applied a powder form feed mixtures. Nutritive value of feed mixtures was the same in each experimental group during the whole experiment and in accordance with the physiological needs of broiler chickens. We fed the 1st experimental group with a basal diet enriched by feed additive from chestnut tree and lemon fruit extracts (50 g/100 kg). As for the 2nd experimental group, we applied feed additive from citrus fruits extracts through the drinking water (100 mL/100 L). In the 2nd part of our experiment, we compared results obtained from two experimental groups with other four groups of diet. We applied other phytogenic additives to these four groups and we did not take into account the origin of the meat sample. We measured indicators of the chemical composition of protein, fat, water and cholesterol on a sample (50 g) of breast and thigh muscle without skin by the method of FT IR by use of the apparatus Nicolet 6700. Detected relations between nutrients of breast and thigh muscles were defined by correlation coefficient of -0.6 ≤ r ≥ +0.6. When additive with chestnut tree and lemon fruit extracts was used, we detected a negative correlation (p ≤0.01) between protein and cholesterol of breast muscle. In thigh muscle, the negative correlation was observed between protein and energy (p ≤0.05), protein and fat (p ≤0.01) as well as fat and water. The only positive correlation was detected between protein and cholesterol of breast muscle (p ≤0.01), with additive citrus fruits extract. When nutrition and parts of carcass, from which muscles originate, were disregarded, protein of meat increased, energy and fat decreased (p ≤0.001). When fat of meat increased, energy increased (p >0.05) as well, but water decreased (p ≤0.05; p ≤0.001).

Biosurfactant Production by Pseudomonas aeruginosa from Renewable Resources.

This study deals with production and characterization of biosurfactant from renewable resources by Pseudomonas aeruginosa. Biosurfactant production was carried out in 3L fermentor using waste motor lubricant oil and peanut oil cake. Maximum biomass (11.6mg/ml) and biosurfactant production (8.6mg/ml) occurred with peanut oil cake at 120 and 132h respectively. Characterization of the biosurfactant revealed that, it is a lipopeptide with chemical composition of protein (50.2%) and lipid (49.8%). The biosurfactant (1mg/ml) was able to emulsify waste motor lubricant oil, crude oil, peanut oil, kerosene, diesel, xylene, naphthalene and anthracene, comparatively the emulsification activity was higher than the activity found with Triton X-100 (1mg/ml). Results obtained in the present study showed the possibility of biosurfactant production using renewable, relatively inexpensive and easily available resources. Emulsification activity found with the biosurfactant against different hydrocarbons showed its possible application in bioremediation of environments polluted with various hydrocarbons.

Sorption isotherm of corn distillers dried grains with solubles (DDGS) and its prediction using chemical composition

Corn distillers dried grains with solubles (DDGS) has high feed value due to its nutritive contents. The ratio of wet distillers grains (WDG) and condensed distillers solubles (CDS) added during the production process determines the chemical composition of DDGS. Effect of changing this ratio on water sorption behaviour of DDGS, at different temperature, was studied. Five mathematical models were evaluated to explain the sorption behaviour of DDGS. Prediction of sorption isotherm from chemical composition using a four-component model was also investigated. DDGS followed a BET Type III isotherm with higher equilibrium moisture content at increasing relative humidity. Difference in the sorption isotherm curves of DDGS samples reduced as equilibrium relative humidity increased. Equilibrium moisture content of DDGS samples reduced with lowering of CDS quantity added during production process. Modified Halsey equation was found suitable for mathematically explaining the sorption behaviour of DDGS. Binding energy of water molecule with DDGS increased with lowering of CDS level. Sorption behaviour of DDGS can be predicted from the chemical composition of protein, sugar, minerals, starch, fibre and glycerol. Increase in CDS level increased the percent relative deviation of predicted values calculated using the modified four-component model and might be due to the interaction between the chemical compounds present in the samples.

Comparative study of the functional properties of bovine globin isolates and sodium caseinate

Two methods used for extraction of globin from bovine blood were tested in terms of effiency, protein recovery and solvent residues. A comparative study with commercial sodium caseinate was made concerning the chemical composition and the functional properties of these proteins. Also, the effect of the NaCl addition on these properties was evaluated. Although the efficiency of the carboxymethyl-cellulose method was inferior than that of the acidified acetone, the absence of residual organic solvents in the globin makes it a more reliable method to prepare globins to be used in foodstuff. The chemical composition of proteins was affected by the method of extraction and the iron content of the globin obtained by the former method was more than three times higher than that using CMC. In general, the NaCl additon was harmful for the functional properties of the studied proteins, mostly for a salt concentration close to that used in meat products (0.25 mol/l).

The Nature of Tunneling Pathway and Average Packing Density Models for Protein-Mediated Electron Transfer

The last 30 years have witnessed the development of increasingly successful theoretical approaches to predicting how a protein's chemical composition and three-dimensional structure influence its propensity to mediate electron-transfer reactions. Analysis has progressed from uniform-barrier models that neglect atomic detail, to pathway models that incorporate the specific nature of the bonding and the protein fold, to multipathway models that add coherently the contributions of pathways, to methods that average over accessible geometries. Large-scale electronic structure methods remain of somewhat limited use because: the demands of geometry sampling and electronic structure calculation are considerable, especially for slower ET events; qualitative new insights arising from the more intensive analysis have been moderate; and structure−function relations become increasingly difficult to derive from more complex models. For these reasons, simple models remain both useful and popular. The simplest structure...