Amino Acid Conjugated Sophorolipids:  A New Family of Biologically Active Functionalized Glycolipids

2006 ◽  
Vol 17 (6) ◽  
pp. 1523-1529 ◽  
Author(s):  
Abul Azim ◽  
Vishal Shah ◽  
Gustavo F. Doncel ◽  
Nicholas Peterson ◽  
Wei Gao ◽  
...  
Keyword(s):  
Amino Acid ◽  
Biologically Active ◽  
New Family

Predicting the Strength of Stacking Interactions Between Heterocycles and Aromatic Amino Acid Side Chains

2019 ◽  
Author(s):  
Andrea N. Bootsma ◽  
Analise C. Doney ◽  
Steven Wheeler
Keyword(s):  
Amino Acid ◽  
Binding Sites ◽  
Aromatic Amino Acid ◽  
Aromatic Amino Acids ◽  
Biologically Active ◽  
Side Chains ◽  
Stacking Interactions ◽  
Inhibitor Binding ◽  
Protein Binding Sites ◽  
Amino Acid Side Chains

<p>Despite the ubiquity of stacking interactions between heterocycles and aromatic amino acids in biological systems, our ability to predict their strength, even qualitatively, is limited. Based on rigorous <i>ab initio</i> data, we have devised a simple predictive model of the strength of stacking interactions between heterocycles commonly found in biologically active molecules and the amino acid side chains Phe, Tyr, and Trp. This model provides rapid predictions of the stacking ability of a given heterocycle based on readily-computed heterocycle descriptors. We show that the values of these descriptors, and therefore the strength of stacking interactions with aromatic amino acid side chains, follow simple predictable trends and can be modulated by changing the number and distribution of heteroatoms within the heterocycle. This provides a simple conceptual model for understanding stacking interactions in protein binding sites and optimizing inhibitor binding in drug design.</p>

Analogues of the cholecystokinin octapeptide modified in the central part of the molecule

1991 ◽  
Vol 56 (9) ◽  
pp. 1963-1970 ◽  
Author(s):  
Jan Hlaváček ◽  
Václav Čeřovský ◽  
Jana Pírková ◽  
Pavel Majer ◽  
Lenka Maletínská ◽  
...  
Keyword(s):  
Amino Acid ◽  
Biological Activities ◽  
Point Of View ◽  
Biologically Active ◽  
Side Chain ◽  
Amino Acid Residues ◽  
Cholecystokinin Octapeptide ◽  
Biological Tests ◽  
Biological Potency ◽  
Biologically Active Conformation

In a series of analogues of the cholecystokinin octapeptide (CCK-8) the amino acid residues were gradually modified by substituting Gly by Pro in position 4, Trp by His in position 5, Met by Cle in position 6, or the Gly residue was inserted between Tyr and Met in positions 2 and 3 of the peptide chain, and in the case of the cholecystokinin heptapeptide (CCK-7) the Met residues were substituted by Nle or Aib. These peptides were investigated from the point of view of their biological potency in the peripheral and central region. From the results of the biological tests it follows that the modifications carried out in these analogues and in their Nα-Boc derivatives mean a suppression of the investigated biological activities by 2-3 orders of magnitude (at a maximum dose of the tested substance of 2 . 10-2 mg per animal).This means that a disturbance of the assumed biologically active conformation of CCK-8, connected with a considerable decrease of the biological potency of the molecule, takes place not only after introduction of the side chain into its centre (substitution of Gly4), but also after the modification of the side chains of the amino acids or by extension of the backbone in further positions around this central amino acid.

scholarly journals Hybrid Cyclobutane/Proline-Containing Peptidomimetics: The Conformational Constraint Influences Their Cell-Penetration Ability

2021 ◽  
Vol 22 (10) ◽  
pp. 5092
Author(s):  
Ona Illa ◽  
Jimena Ospina ◽  
José-Emilio Sánchez-Aparicio ◽  
Ximena Pulido ◽  
María Ángeles Abengozar ◽  
...  
Keyword(s):  
Amino Acid ◽  
Cell Penetrating Peptides ◽  
Cell Uptake ◽  
Relevant Parameter ◽  
Intracellular Accumulation ◽  
Peptide Backbone ◽  
New Family ◽  
Cell Line Hela ◽  
Penetration Ability ◽  
Tumoral Cell

A new family of hybrid β,γ-peptidomimetics consisting of a repetitive unit formed by a chiral cyclobutane-containing trans-β-amino acid plus a Nα-functionalized trans-γ-amino-l-proline joined in alternation were synthesized and evaluated as cell penetrating peptides (CPP). They lack toxicity on the human tumoral cell line HeLa, with an almost negligible cell uptake. The dodecapeptide showed a substantial microbicidal activity on Leishmania parasites at 50 µM but with a modest intracellular accumulation. Their previously published γ,γ-homologues, with a cyclobutane γ-amino acid, showed a well-defined secondary structure with an average inter-guanidinium distance of 8–10 Å, a higher leishmanicidal activity as well as a significant intracellular accumulation. The presence of a very rigid cyclobutane β-amino acid in the peptide backbone precludes the acquisition of a defined conformation suitable for their cell uptake ability. Our results unveiled the preorganized charge-display as a relevant parameter, additional to the separation among the charged groups as previously described. The data herein reinforce the relevance of these descriptors in the design of CPPs with improved properties.

Synthesis of a Biologically Active Nonadecapeptide Corresponding to the First Nineteen Amino Acid Residues of Adrenocorticotropins1a

1961 ◽  
Vol 83 (21) ◽  
pp. 4449-4457 ◽  
Author(s):  
Choh Hao Li ◽  
Johannes Meienhofer ◽  
Eugen Schnabel ◽  
David Chung ◽  
Tung-Bin Lo ◽  
...  
Keyword(s):  
Amino Acid ◽  
Biologically Active ◽  
Amino Acid Residues

scholarly journals Chemical composition and antioxidant potential of Acacia leucophloea Roxb

2013 ◽  
Vol 72 (1) ◽  
pp. 133-144 ◽  
Author(s):  
Muhammad Zia-Ul-Haq ◽  
Sanja Ćavar ◽  
Mughal Qayum ◽  
Inamullah Khan ◽  
Shakeel Ahmad
Keyword(s):  
Amino Acid ◽  
Chemical Composition ◽  
Amino Acid Profile ◽  
Major Fatty Acid ◽  
Biologically Active ◽  
Antioxidant Potential ◽  
Limited Information ◽  
Methanolic Extracts ◽  
Antioxidant Agent ◽  
Acacia Leucophloea

Abstract The aim of this study was to evaluate the compositional and nutritional potential of methanolic extracts of various parts of Acacia leucophloea Roxb. concerning the chemical composition and antioxidant potential of which limited information is available. Compositional studies indicated carbohydrates as major components in both seed and pods. Despite differences in mineral content among the leaves, pods and seeds, calcium was found in the highest amount and zinc in the lowest. The amino acid profile indicated aspartic acid as the major amino acid and proline as the minor. Among protein fractions, globulin was present in higher amounts than other fractions. Linoleic acid was the major fatty acid detected in the oil from both pods and seeds, while g-tocopherol was the major component of the tocopherol observed from same oil. Moreover, significant antioxidant potential was observed from the extracts of all three parts investigated. The results obtained in this study clearly indicate that A. leucophloea has a sufficient potential for use as a natural antioxidant agent. Further phytochemical studies will be performed for specification of the biologically active principles.

scholarly journals Transforming growth factor alpha: mutation of aspartic acid 47 and leucine 48 results in different biological activities.

1988 ◽  
Vol 8 (3) ◽  
pp. 1247-1252 ◽  
Author(s):  
E Lazar ◽  
S Watanabe ◽  
S Dalton ◽  
M B Sporn
Keyword(s):  
Amino Acids ◽  
Biological Activity ◽  
Amino Acid ◽  
Growth Factor ◽  
Aspartic Acid ◽  
Transforming Growth Factor ◽  
Biologically Active ◽  
Single Amino Acid ◽  
Transforming Growth Factor Alpha ◽  
Factor Alpha

To study the relationship between the primary structure of transforming growth factor alpha (TGF-alpha) and some of its functional properties (competition with epidermal growth factor (EGF) for binding to the EGF receptor and induction of anchorage-independent growth), we introduced single amino acid mutations into the sequence for the fully processed, 50-amino-acid human TGF-alpha. The wild-type and mutant proteins were expressed in a vector by using a yeast alpha mating pheromone promoter. Mutations of two amino acids that are conserved in the family of the EGF-like peptides and are located in the carboxy-terminal part of TGF-alpha resulted in different biological effects. When aspartic acid 47 was mutated to alanine or asparagine, biological activity was retained; in contrast, substitutions of this residue with serine or glutamic acid generated mutants with reduced binding and colony-forming capacities. When leucine 48 was mutated to alanine, a complete loss of binding and colony-forming abilities resulted; mutation of leucine 48 to isoleucine or methionine resulted in very low activities. Our data suggest that these two adjacent conserved amino acids in positions 47 and 48 play different roles in defining the structure and/or biological activity of TGF-alpha and that the carboxy terminus of TGF-alpha is involved in interactions with cellular TGF-alpha receptors. The side chain of leucine 48 appears to be crucial either indirectly in determining the biologically active conformation of TGF-alpha or directly in the molecular recognition of TGF-alpha by its receptor.

scholarly journals Primary Structure Analysis of Antifungal Peptides from Cultivated and Wild Cereals

Plants ◽  
2018 ◽  
Vol 7 (3) ◽  
pp. 74 ◽  
Author(s):  
Eugene Rogozhin ◽  
Dmitry Ryazantsev ◽  
Alexey Smirnov ◽  
Sergey Zavriev
Keyword(s):  
Antimicrobial Activity ◽  
Amino Acid ◽  
Antifungal Activity ◽  
Antimicrobial Peptides ◽  
Structure Analysis ◽  
Primary Structure ◽  
Biologically Active ◽  
Amino Acid Residues ◽  
Wild Cereals ◽  
Determining Factor

Cereal-derived bioactive peptides with antimicrobial activity have been poorly explored compared to those from dicotyledonous plants. Furthermore, there are a few reports addressing the structural differences between antimicrobial peptides (AMPs) from cultivated and wild cereals, which may shed light on significant varieties in the range and level of their antimicrobial activity. We performed a primary structure analysis of some antimicrobial peptides from wild and cultivated cereals to find out the features that are associated with the much higher antimicrobial resistance characteristic of wild plants. In this review, we identified and analyzed the main parameters determining significant antifungal activity. They relate to a high variability level in the sequences of C-terminal fragments and a high content of hydrophobic amino acid residues in the biologically active defensins in wild cereals, in contrast to AMPs from cultivated forms that usually exhibit weak, if any, activity. We analyzed the similarity of various physicochemical parameters between thionins and defensins. The presence of a high divergence on a fixed part of any polypeptide that is close to defensins could be a determining factor. For all of the currently known hevein-like peptides of cereals, we can say that the determining factor in this regard is the structure of the chitin-binding domain, and in particular, amino acid residues that are not directly involved in intermolecular interaction with chitin. The analysis of amino acid sequences of alpha-hairpinins (hairpin-like peptides) demonstrated much higher antifungal activity and more specificity of the peptides from wild cereals compared with those from wheat and corn, which may be associated with the presence of a mini cluster of positively charged amino acid residues. In addition, at least one hydrophobic residue may be responsible for binding to the components of fungal cell membranes.

scholarly journals AMINO ACID COMPOSITION OF LEAVES OF THREE SPECIES OF ARTEMISIA L. GROWING IN THE ELTON REGION

2021 ◽  
pp. 219-225
Author(s):  
Галина Табаленкова
Keyword(s):  
Amino Acids ◽  
Czech Republic ◽  
Amino Acid ◽  
Dry Weight ◽  
Biologically Active ◽  
Raw Material ◽  
Buffer System ◽  
Amino Acid Analyzer ◽  
Growing Conditions ◽  
High Level

The results of studies of the qualitative composition and quantitative content of amino acids (AAs) in the leaves of three plant species of the genus Artemisia, widespread in the Elton region, were presented. Protein AAs were determined on an AAA T-339 amino acid analyzer (Czech Republic) after hydrolysis of a sample in 6N HCl at 105 °C for 24 h, free AAs – on an AAA-400 amino acid analyzer (Czech Republic) in a lithium buffer system. The protein AAs amount varied from 66 mg / g in A. lerchiana to 113 mg / g dry weight in A. santonica. 17 AAs were found in composition of these species, aspartic and glutamic acids were dominant. The content of free AAs varied from 4.4 mg / g in A. santonica to 8.3 mg / g dry weight in A. pauciflora. 14 AAs have been identified, among them proline was the predominant free AA. The share of proline was 75-81% of the total free AAs. Among the minor components, 3-4 compounds with a content above 2% dominated. The free AAs contain 3 non-proteinogenic ones (ornithine, citruline, and γ-aminobutyric acid). A. lerchiana and A. pauciflora species were similar in protein and free amino acids, probably due to the same growing conditions. A high level of free proline, together with a complex of biologically active substances in Artemisia species, which grow abundantly in the Elton region, allow to consider the possibility of their use as a medicinal raw material.

scholarly journals Reduction of Herbicidal Toxicoses on Plants Using Berkana and Izabion Organomineral Fertilizers

2021 ◽  
Vol 901 (1) ◽  
pp. 012071
Author(s):  
V N Demidova ◽  
T I Smetanina ◽  
M A Kuznetsova
Keyword(s):  
Experimental Data ◽  
Amino Acid ◽  
Crop Rotation ◽  
Biologically Active Compounds ◽  
Seedling Stage ◽  
Biologically Active ◽  
Active Compounds ◽  
Plant Cultivation ◽  
Negative Aftereffect ◽  
Negative Effect

Abstract Today herbicidal treatments become an obligatory component of agrotechnical activities required for plant cultivation. At the same time, being biologically active compounds, herbicides may negatively influence on plants during crop rotation. In this study the experimental data confirmed the negative effect of a metribuzin-based herbicide applied on potato towards the next crops (cucumber and lentil). Treatment of these crops with amino acid-based bioorganic fertilizers (Berkana and Izabion) in a seedling stage reduced the manifestations of the negative aftereffect of the herbicidal stress on the tested plants.

scholarly journals Synthesis of New 6,7(N,O)-Heterocyclic 1,4-Naphthoquinones

2021 ◽  
Vol 11 (6) ◽  
pp. 13903-13910
Keyword(s):  
Amino Acid ◽  
High Activity ◽  
Biologically Active ◽  
Amino Acid Derivatives ◽  
Antimicrobial Substances ◽  
Derivatives Of

As a result of the carried out research it was synthesized an order of new potentially biologically active modified N-,O-contained heterocycles on the base of amino acid derivatives of 2,6,7-nitrogen substituted-3-chloro-1,4-naphthoquinone. It was established that among synthesized compounds, there are potential antimicrobial substances with high activity.

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