Synthesis ofβ-Peptides withβ-Helices from New C-Linked Carbo-β-Amino Acids: Study on the Impact of Carbohydrate Side Chains

2009 ◽  
Vol 4 (1) ◽  
pp. 181-193 ◽  
Author(s):  
Gangavaram V. M. Sharma ◽  
Kota Sudhakar Rao ◽  
Rapolu Ravi ◽  
Kongari Narsimulu ◽  
Pendem Nagendar ◽  
...  
Keyword(s):  
Amino Acids ◽  
Side Chains ◽  
The Impact

scholarly journals Unexpected Trends in the Hydrophobicity of Fluorinated Amino Acids Reflect Competing Changes in Polarity and Conformation

2018 ◽  
Author(s):  
João R. Robalo ◽  
Ana Vila Verde
Keyword(s):  
Amino Acids ◽  
Free Energy ◽  
Side Chain ◽  
Side Chains ◽  
Hydration Free Energy ◽  
Crossover Point ◽  
Fluorinated Amino Acids ◽  
Road Map ◽  
Alkyl Side Chains ◽  
The Impact

<div><div><div><p>Fluorination can dramatically improve the thermal and proteolytic stability of proteins and their enzymatic activity. Key to the impact of fluorination on protein properties is the hydrophobicity of fluorinated amino acids. We use molecular dynamics simulations, together with a new fixed-charge, atomistic force field, to quantify the changes in hydration free energy for amino acids with alkyl side chains and with 1 to 6 –CH to –CF side chain substitutions. Fluorination changes the hydration free energy by 1.5 to +2 kcal mol<sup>-</sup>1, but the number of fluorines is a poor predictor of hydrophobicity. Changes in hydration free energy reflect two main contributions: i) fluorination alters side chain-water interactions; we identify a crossover point from hydrophilic to hydrophobic fluoromethyl groups which may be used to estimate the hydrophobicity of fluorinated alkyl side-chains; ii) fluorination alters the number of backbone-water hydrogen bonds via changes in the relative side chain-backbone conformation. Our results offer a road map to mechanistically understand how fluorination alters hydrophobicity of (bio)polymers.</p></div></div></div>

scholarly journals Unexpected Trends in the Hydrophobicity of Fluorinated Amino Acids Reflect Competing Changes in Polarity and Conformation

2018 ◽  
Author(s):  
João R. Robalo ◽  
Ana Vila Verde
Keyword(s):  
Amino Acids ◽  
Free Energy ◽  
Side Chain ◽  
Side Chains ◽  
Hydration Free Energy ◽  
Crossover Point ◽  
Fluorinated Amino Acids ◽  
Road Map ◽  
Alkyl Side Chains ◽  
The Impact

<div><div><div><p>Fluorination can dramatically improve the thermal and proteolytic stability of proteins and their enzymatic activity. Key to the impact of fluorination on protein properties is the hydrophobicity of fluorinated amino acids. We use molecular dynamics simulations, together with a new fixed-charge, atomistic force field, to quantify the changes in hydration free energy for amino acids with alkyl side chains and with 1 to 6 –CH to –CF side chain substitutions. Fluorination changes the hydration free energy by 1.5 to +2 kcal mol<sup>-</sup>1, but the number of fluorines is a poor predictor of hydrophobicity. Changes in hydration free energy reflect two main contributions: i) fluorination alters side chain-water interactions; we identify a crossover point from hydrophilic to hydrophobic fluoromethyl groups which may be used to estimate the hydrophobicity of fluorinated alkyl side-chains; ii) fluorination alters the number of backbone-water hydrogen bonds via changes in the relative side chain-backbone conformation. Our results offer a road map to mechanistically understand how fluorination alters hydrophobicity of (bio)polymers.</p></div></div></div>

Synthesis and conformational studies of α/β2,3-peptides derived from alternating β2,3-amino acids and l-Ala repeats

2015 ◽  
Vol 39 (5) ◽  
pp. 3295-3309 ◽  
Author(s):  
Gangavaram V. M. Sharma ◽  
Tailor Sridhar ◽  
Bacchu Veena ◽  
Pothula Purushotham Reddy ◽  
Sheri Venkata Reddy ◽  
...  
Keyword(s):  
Amino Acids ◽  
Side Chains ◽  
Conformational Studies ◽  
New Class ◽  
The Impact

A new class of α/β2,3-peptides were synthesized from C-linked carbo-β2,3-amino acids (β2,3-Caas) and investigated to understand the impact of the side chains (allyl/propargyl) at the Cα-position on their conformations.

Hydrogen Cyanide Polymers from the Impact of Comet P/Shoemaker-Levy 9 on Jupiter

1997 ◽  
Vol 161 ◽  
pp. 179-187
Author(s):  
Clifford N. Matthews ◽  
Rose A. Pesce-Rodriguez ◽  
Shirley A. Liebman
Keyword(s):  
Amino Acids ◽  
Solar System ◽  
Hydrogen Cyanide ◽  
Nitrogen Heterocycles ◽  
Laboratory Studies ◽  
Heterogeneous Solids ◽  
The Many ◽  
Comet Halley ◽  
The Impact ◽  
By Products

AbstractHydrogen cyanide polymers – heterogeneous solids ranging in color from yellow to orange to brown to black – may be among the organic macromolecules most readily formed within the Solar System. The non-volatile black crust of comet Halley, for example, as well as the extensive orangebrown streaks in the atmosphere of Jupiter, might consist largely of such polymers synthesized from HCN formed by photolysis of methane and ammonia, the color observed depending on the concentration of HCN involved. Laboratory studies of these ubiquitous compounds point to the presence of polyamidine structures synthesized directly from hydrogen cyanide. These would be converted by water to polypeptides which can be further hydrolyzed to α-amino acids. Black polymers and multimers with conjugated ladder structures derived from HCN could also be formed and might well be the source of the many nitrogen heterocycles, adenine included, observed after pyrolysis. The dark brown color arising from the impacts of comet P/Shoemaker-Levy 9 on Jupiter might therefore be mainly caused by the presence of HCN polymers, whether originally present, deposited by the impactor or synthesized directly from HCN. Spectroscopic detection of these predicted macromolecules and their hydrolytic and pyrolytic by-products would strengthen significantly the hypothesis that cyanide polymerization is a preferred pathway for prebiotic and extraterrestrial chemistry.

Chemical Composition and Metal Speciation in Porewaters from the Upper Qu’Appelle River Basin, Saskatchewan

1993 ◽  
Vol 28 (1) ◽  
pp. 83-110 ◽  
Author(s):  
Richard E. Farrell ◽  
Jae E. Yang ◽  
P. Ming Huang ◽  
Wen K. Liaw
Keyword(s):  
Amino Acids ◽  
Trace Metal ◽  
River Basin ◽  
Drainage Basin ◽  
Metal Speciation ◽  
Anthropogenic Activities ◽  
High Concentration ◽  
Metal Concentrations ◽  
Carbonate Equilibria ◽  
The Impact

Abstract Porewater samples from the upper Qu’Appelle River basin in Saskatchewan, Canada, were analyzed to obtain metal, inorganic ligand and amino add profiles. These data were used to compute the aqueous speciation of the metals in each porewater using the computer program GEOCHEM-PC. The porewaters were classified as slightly to moderately saline. Metal concentrations reflected both the geology of the drainage basin and the impact of anthropogenic activities. Whereas K and Na were present almost entirely as the free aquo ions, carbonate equilibria dominated the speciation of Ca. Mg and Mn (the predominant metal ligand species were of the type MCO3 (s). MCO30. and MHCO3+). Trace metal concentrations were generally within the ranges reported for non-polluted freshwater systems. Whereas the speciation of the trace metals Cr(III) and Co(II) was dominated by carbonate equilibria, Hg(II)-, Zn(II)- and Fe(II)-speciation was dominated by hydroxy-metal complexes of the type M(OH)+ and M(OH)2°. The speciation of Fe(III) was dominated by Fe(OH)3 (s). In porewaters with high chloride concentrations (&gt; 2 mM), however, significant amounts of Hg(II) were bound as HgCl20 and HgClOH0. The aqueous speciation of Al was dominated by Al(OH)4− and Al2Si2O4(OH)6 (s). Total concentrations of dissolved free amino acids varied from 15.21 to 25.17 umole L−1. The most important metal scavenging amino acids were histidine (due to high stability constants for the metal-histidine complexes) and tryptophan (due to its relatively high concentration in the porewaters. i.e., 5.96 to 7.73 umole L−1). Secondary concentrations of various trace metal-amino add complexes were computed for all the porewaters, but metal-amino acid complexes dominated the speciation of Cu(II) in all the porewaters and Ni(II) in two of the porewaters.

scholarly journals Mycosporine-Like Amino Acids from Red Macroalgae: UV-Photoprotectors with Potential Cosmeceutical Applications

2021 ◽  
Vol 11 (11) ◽  
pp. 5112
Author(s):  
Julia Vega ◽  
Geniane Schneider ◽  
Bruna R. Moreira ◽  
Carolina Herrera ◽  
José Bonomi-Barufi ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Amino Acids ◽  
High Performance ◽  
Nitrogen Availability ◽  
Antioxidant Properties ◽  
Published Data ◽  
Diverse Group ◽  
Red Macroalgae ◽  
Thermo Stability ◽  
The Impact

Macroalgae belong to a diverse group of organisms that could be exploited for biomolecule application. Among the biocompounds found in this group, mycosporine-like amino acids (MAAs) are highlighted mainly due to their photoprotection, antioxidant properties, and high photo and thermo-stability, which are attractive characteristics for the development of cosmeceutical products. Therefore, here we revise published data about MAAs, including their biosynthesis, biomass production, extraction, characterization, identification, purification, and bioactivities. MAAs can be found in many algae species, but the highest concentrations are found in red macroalgae, mainly in the order Bangiales, as Porphyra spp. In addition to the species, the content of MAAs can vary depending on environmental factors, of which solar radiation and nitrogen availability are the most influential. MAAs can confer photoprotection due to their capacity to absorb ultraviolet radiation or reduce the impact of free radicals on cells, among other properties. To extract these compounds, different approaches can be used. The efficiency of these methods can be evaluated with characterization and identification using high performance liquid chromatography (HPLC), associated with other apparatus such as mass spectrometry (MS) and nuclear magnetic resonance (NMR). Therefore, the data presented in this review allow a broad comprehension of MAAs and show perspectives for their inclusion in cosmeceutical products.

scholarly journals Empaglifozin induces changes in the liver metabolome of diabetic rats

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
A Aragon Herrera ◽  
S Feijoo-Bandin ◽  
M Otero Santiago ◽  
S Moranha Fernandez ◽  
L Anido Varela ◽  
...  
Keyword(s):  
Amino Acids ◽  
Liver Fibrosis ◽  
Diabetic Rats ◽  
Liver Fat ◽  
Favorable Effect ◽  
Funding Source ◽  
Metabolomics Data ◽  
Fat Accumulation ◽  
Glucose Levels ◽  
The Impact

Abstract Background Empagliflozin is a potent, highly selective sodium glucose cotransporter-2 (SGLT2) inhibitor used as an effective and well-tolerated antihyperglycaemic agent. Beyond lowering glucose, empagliflozin exerts a favorable effect on a number of nonglycaemic outcomes, including modest reductions in bodyweight and blood pressure, and it has cardioprotective and renoprotective properties in patients with T2D and established cardiovascular disease (EMPA-REG OUTCOME). Purpose Since liver fat content represents a risk factor for cardiovascular diseases, and empagliflozin has been recently suggested to be able to contribute to the early treatment of nonalcoholic fatty liver disease in T2D, we aimed to study the effect of the empagliflozin treatment in the liver metabolome of type 2 diabetic rats. Methods Male ZDF-Leprfa/fa rats were treated with 30 mg/kg/d of empagliflozin p.o for six weeks. Metabolic profiling of the hepatic tissue was analyzed using UHPLC-MS based platforms. We performed a hematoxylin/eosin staining to determine the tissue integrity and liver fat accumulation, and a Masson's trichrome staining to analyze liver fibrosis. All animals were maintained and euthanized following protocols approved by the Animal Care Committee of the University of Santiago de Compostela in accordance with European Union Directive 2010/63. Results Empaglifozin treatment reduced blood glucose levels to normal (128.2±6.51 mg/dL), while untreated control rats showed high glucose levels (404.3±17.49 mg/dL). Hepatic histological analysis did not show differences regarding neither fat accumulation nor fibrosis between empagliflozin treated and control rats. Circulating levels of cholesterol, HDL, LDL, GTP, GGT triglycerides remained unaltered after empaglifozin treatment vs. control. 384 metabolites were analyzed in the liver tissue samples, observing significantly increased levels of 10 types of glycerolipids, 24 phosphatidylcholines, 8 amino acids, 1 polyunsaturated fatty acid, 4 lysophosphatidylethanolamines, 7 lysophosphatidylinositols, 1 carboxylic acid and 1 nucleoside in the empagliflozin treated rats with respect to the control group. In addition, treatment with empagliflozin produced a significant decrease of 1 glycerolipid, 1 phosphatidylcholine, 1 bile acid, 1 nucleoside and the NAD oxidoreduction coenzyme. Conclusions We demonstrated that empagliflozin significantly modify the liver content of the different lipid species, with the most relevant altered metabolic classes belonging to glycerophospholipids, especially monoacyl-species, and aromatic amino acids. Considering the suggested potential beneficial effect of the treatment with empagliflozin in the prevention of liver fibrosis, our metabolomics data can help to evaluate the impact and the mechanism of action of SGLT2 inhibitors at hepatic level. Funding Acknowledgement Type of funding source: Private company. Main funding source(s): Boehringer Ingelheim

scholarly journals 129 Effects of a multi-strain Bacillus subtilis-based direct-fed microbial on growth performance, nutrient digestibility, and colonic pH in diets fed to weanling pigs

2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 101-102
Author(s):  
Jaron R Lewton ◽  
Adrienne Woodward ◽  
Ronny Moser ◽  
Kyan M Thelen ◽  
Adam J Moeser ◽  
...  
Keyword(s):  
Amino Acids ◽  
Bacillus Subtilis ◽  
Growth Performance ◽  
Distal Colon ◽  
Nutrient Digestibility ◽  
Nursery Pigs ◽  
Fiber Digestion ◽  
Males And Females ◽  
Dietary Treatments ◽  
The Impact

Abstract A study was conducted to evaluate the effects of a multi-strain Bacillus subtilis-based direct-fed microbial (DFM) on apparent digestibility and colonic pH of nursery pigs. Eighty pigs, of equal number of barrows and gilts (initial BW: 6.99 ± 1.67 kg), were weaned at 21 ± 1 d and randomly allotted to sixteen pens, with five pigs per pen. Two dietary treatments were implemented, a basal control (CON) and a control plus DFM (DFM). Both diets were corn, soybean meal, and distillers dried grains based, formulated to meet all or exceed all nutritional requirements, and manufactured on site. Diets were fed for 42 days. Performance measures were recorded weekly. On d 21 and 42 of the experiment, one pig per pen was randomly selected and euthanized, with equal number of males and females represented. Digestibility of specific nutrients was evaluated within the duodenum, jejunum, ileum, ascending and distal colon. There were no overall differences in growth performance. Overall means ± SD were 0.51 ± 0.05 kg/d, 0.79 ± 0.05 kg/d and 0.66 ± 0.05 for ADG, ADFI, and G:F, respectively. Digestibility of tryptophan within the jejunum tended (P = 0.06) to increase with addition of DFM, as did cysteine (P = 0.12) and methionine (P = 0.10). The analysis also suggested that the impact of the DFM on the digestibility of amino acids may be early in the nursery phase. The pH of contents in ascending colon, a possible indicator of varied fiber digestion, did not differ. Likewise, no differences were observed between treatment in apparent total tract nitrogen and energy digestibility (analysis of distal colon contents). The addition of a multi-strain Bacillus subtilis-based DFM appears to impact digestibility of select amino acids depending upon location in the gastrointestinal tract.

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