scholarly journals The function of peptide-mimetic anionic groups and salt bridges in the antimicrobial activity and conformation of cationic amphiphilic copolymers

RSC Advances ◽  
2021 ◽  
Vol 11 (36) ◽  
pp. 22044-22056
Author(s):  
Rajani Bhat ◽  
Leanna L. Foster ◽  
Garima Rani ◽  
Satyavani Vemparala ◽  
Kenichi Kuroda
Keyword(s):  
Antimicrobial Activity ◽  
Amino Acid ◽  
Salt Bridges ◽  
Amphiphilic Copolymers ◽  
Polymer Conformation ◽  
Peptide Mimetic ◽  
Anionic Groups

Amino acid-mimetic anionic groups and salt bridges in cationic amphiphilic copolymers control the polymer conformation and dynamics in solution.

scholarly journals Synthesis and antimicrobial activity of some novel 1,2-dihydro-[1,2,4]triazolo[1,5-a]pyrimidines bearing amino acid moiety

RSC Advances ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 2905-2916
Author(s):  
Mounir A. A. Mohamed ◽  
Adnan A. Bekhit ◽  
Omyma A. Abd Allah ◽  
Asmaa M. Kadry ◽  
Tamer M. Ibrahim ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Amino Acid ◽  
Green Chemistry ◽  
Antimicrobial Activities ◽  
Amino Acid Derivatives ◽  
Acid Moiety ◽  
Amino Acid Moiety

A new series of [1,2,4]-triazole bearing amino acid derivatives were synthesized under green chemistry conditions and evaluated for their antimicrobial activities.

scholarly journals Development of Antimicrobial Stapled Peptides Based on Magainin 2 Sequence

Molecules ◽  
2021 ◽  
Vol 26 (2) ◽  
pp. 444
Author(s):  
Motoharu Hirano ◽  
Chihiro Saito ◽  
Hidetomo Yokoo ◽  
Chihiro Goto ◽  
Ryuji Kawano ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Amino Acid ◽  
Hemolytic Activity ◽  
Helical Structure ◽  
Antimicrobial Activities ◽  
Side Chain ◽  
Membrane Disruption ◽  
Amino Acid Residues ◽  
Electrophysiological Measurements ◽  
Cell Membrane Disruption

Magainin 2 (Mag2), which was isolated from the skin of the African clawed frog, is a representative antimicrobial peptide (AMP) that exerts antimicrobial activity via microbial membrane disruption. It has been reported that the helicity and amphipathicity of Mag2 play important roles in its antimicrobial activity. We investigated and recently reported that 17 amino acid residues of Mag2 are required for its antimicrobial activity, and accordingly developed antimicrobial foldamers containing α,α-disubstituted amino acid residues. In this study, we further designed and synthesized a set of Mag2 derivatives bearing the hydrocarbon stapling side chain for helix stabilization. The preferred secondary structures, antimicrobial activities, and cell-membrane disruption activities of the synthesized peptides were evaluated. Our analyses revealed that hydrocarbon stapling strongly stabilized the helical structure of the peptides and enhanced their antimicrobial activity. Moreover, peptide 2 stapling between the first and fifth position from the N-terminus showed higher antimicrobial activity than that of Mag2 against both gram-positive and gram-negative bacteria without exerting significant hemolytic activity. To investigate the modes of action of tested peptides 2 and 8 in antimicrobial and hemolytic activity, electrophysiological measurements were performed.

scholarly journals Rational design of novel amphipathic antimicrobial peptides focused on the distribution of cationic amino acid residues

MedChemComm ◽  
2019 ◽  
Vol 10 (6) ◽  
pp. 896-900 ◽  
Author(s):  
Takashi Misawa ◽  
Chihiro Goto ◽  
Norihito Shibata ◽  
Motoharu Hirano ◽  
Yutaka Kikuchi ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Amino Acid ◽  
Human Cell ◽  
Hemolytic Activity ◽  
Rational Design ◽  
Cell Cytotoxicity ◽  
Amino Acid Residues ◽  
High Antimicrobial Activity ◽  
Cationic Amino Acid ◽  
Helical Peptide

Amphipathic helical peptideStripeshowed high antimicrobial activity, low hemolytic activity, and low human cell cytotoxicity.

scholarly journals Biological and Physico-Chemical Characteristics of Arginine-Rich Peptide Gemini Surfactants with Lysine and Cystine Spacers

2021 ◽  
Vol 22 (7) ◽  
pp. 3299
Author(s):  
Damian Neubauer ◽  
Maciej Jaśkiewicz ◽  
Marta Bauer ◽  
Agata Olejniczak-Kęder ◽  
Emilia Sikorska ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Amino Acid ◽  
Cationic Surfactants ◽  
Antimicrobial Agents ◽  
Gemini Surfactants ◽  
Antimicrobial Activities ◽  
Critical Aggregation Concentration ◽  
Cytotoxic Activities ◽  
Candida Sp ◽  
Enhanced Selectivity

Ultrashort cationic lipopeptides (USCLs) and gemini cationic surfactants are classes of potent antimicrobials. Our recent study has shown that the branching and shortening of the fatty acids chains with the simultaneous addition of a hydrophobic N-terminal amino acid in USCLs result in compounds with enhanced selectivity. Here, this approach was introduced into arginine-rich gemini cationic surfactants. L-cystine diamide and L-lysine amide linkers were used as spacers. Antimicrobial activity against planktonic and biofilm cultures of ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp.) strains and Candida sp. as well as hemolytic and cytotoxic activities were examined. Moreover, antimicrobial activity in the presence of human serum and the ability to form micelles were evaluated. Membrane permeabilization study, serum stability assay, and molecular dynamics were performed. Generally, critical aggregation concentration was linearly correlated with hydrophobicity. Gemini surfactants were more active than the parent USCLs, and they turned out to be selective antimicrobial agents with relatively low hemolytic and cytotoxic activities. Geminis with the L-cystine diamide spacer seem to be less cytotoxic than their L-lysine amide counterparts, but they exhibited lower antibiofilm and antimicrobial activities in serum. In some cases, geminis with branched fatty acid chains and N-terminal hydrophobic amino acid resides exhibited enhanced selectivity to pathogens over human cells.

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 Structural and Functional Consequences of Age-Related Isomerization in α-Crystallins

2018 ◽  
Author(s):  
Yana A. Lyon ◽  
Dylan L. Riggs ◽  
Miranda P. Collier ◽  
Matteo T. Degiacomi ◽  
Justin L.P. Benesch ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Molecular Dynamics ◽  
Amino Acid ◽  
Native Mass Spectrometry ◽  
Salt Bridges ◽  
Loss Of Function ◽  
Post Translational Modification ◽  
Age Related ◽  
Αb Crystallin ◽  
Functional Consequences

AbstractLong-lived proteins are subject to spontaneous degradation and may accumulate a range of modifications over time, including subtle alterations such as isomerization. Recently, tandem-mass spectrometry approaches have enabled the identification and detailed characterization of such peptide isomers, including those differing only in chirality. However, the structural and functional consequences of these perturbations remain largely unexplored. Here we examine the site-specific impact of isomerization of aspartic acid and epimerization of serine in human αA- and αB-crystallin. From a total of 81 sites of modification identified in aged eye lenses, four (αBSer59, αASer162, αBAsp62, αBAsp109) map to crucial oligomeric interfaces. To characterize the effect of isomerization on quaternary assembly, molecular dynamics calculations and native mass spectrometry experiments were performed on recombinant forms of αA- and αB-crystallin that incorporate, or mimic, isomerized residues. In all cases, oligomerization is significantly affected, with epimerization of a single serine residue (αASer162) sufficing to weaken inter-subunit binding dramatically. Furthermore, phosphorylation of αBSer59, known to play an important regulatory role in oligomerization, is severely inhibited by serine epimerization and altered by isomerization of nearby αBAsp62. Similarly, isomerization of αBAsp109 disrupts a vital salt-bridge with αBArg120, a loss previously shown to yield aberrant oligomerization and aggregation in several disease variants. Our results illustrate how isomerization of amino-acid residues, which may seem like a minor structural perturbation, can have profound consequences on protein assembly and activity by disrupting specific hydrogen bonds and salt bridges.Significance StatementProteins play numerous critical roles in our bodies but suffer damage with increasing age. For example, isomerization is a spontaneous post-translational modification that alters the three-dimensional connectivity of an amino acid, yet remains invisible to traditional proteomic experiments. Herein, radical-based fragmentation was used for isomer identification while molecular dynamics and native mass spectrometry were utilized to assess structural consequences. The results demonstrate that isomerization disrupts both oligomeric assembly and phosphorylation in the α-crystallins, which are long-lived proteins in the lens of the eye. The loss of function associated with these modifications is likely connected to age-related diseases such as cataract and neurodegenerative disorders, while the methodologies we present represent a framework for structure-function studies on other isomerized proteins.

scholarly journals Diverse Mechanisms of Antimicrobial Activities of Lactoferrins, Lactoferricins, and Other Lactoferrin-Derived Peptides

2021 ◽  
Vol 22 (20) ◽  
pp. 11264
Author(s):  
Špela Gruden ◽  
Nataša Poklar Ulrih
Keyword(s):  
Antimicrobial Activity ◽  
Amino Acid ◽  
Amino Acid Composition ◽  
Molecular Level ◽  
Antioxidant Activities ◽  
Antimicrobial Activities ◽  
Iron Binding ◽  
Primary Focus ◽  
Binding Glycoprotein

Lactoferrins are an iron-binding glycoprotein that have important protective roles in the mammalian body through their numerous functions, which include antimicrobial, antitumor, anti-inflammatory, immunomodulatory, and antioxidant activities. Among these, their antimicrobial activity has been the most studied, although the mechanism behind antimicrobial activities remains to be elucidated. Thirty years ago, the first lactoferrin-derived peptide was isolated and showed higher antimicrobial activity than the native lactoferrin lactoferricin. Since then, numerous studies have investigated the antimicrobial potencies of lactoferrins, lactoferricins, and other lactoferrin-derived peptides to better understand their antimicrobial activities at the molecular level. This review defines the current antibacterial, antiviral, antifungal, and antiparasitic activities of lactoferrins, lactoferricins, and lactoferrin-derived peptides. The primary focus is on their different mechanisms of activity against bacteria, viruses, fungi, and parasites. The role of their structure, amino-acid composition, conformation, charge, hydrophobicity, and other factors that affect their mechanisms of antimicrobial activity are also reviewed.

Influence of Amino Acid Substitutions in a Recombinant Cow Chymosin Molecule on the Dependence of its Coagulation Activity on the Concentration of Calcium Chloride in Milk

2021 ◽  
Vol 37 (1) ◽  
pp. 81-86
Author(s):  
A.V. Mironova ◽  
V.A. Pushkarev ◽  
J.G. Afanasieva ◽  
D.N. Shcherbakov ◽  
A.P. Rudometov ◽  
...  
Keyword(s):  
Amino Acid ◽  
Calcium Chloride ◽  
Amino Acid Substitutions ◽  
Salt Bridges ◽  
Technological Properties ◽  
Coagulation Activity ◽  
Cheese Making ◽  
Milk Clotting ◽  
Milk Clotting Enzyme ◽  
Milk Mixture

The influence of substitutions of amino acids involved in the formation of salt bridges on the cow chymosin technological properties has been studied. It was shown that point amino acid mutations Asp198→Lys, Asp156→Val and their combination decrease the sensitivity of coagulation activity of engineering recombinant chymosins to change in the concentration of calcium chloride in milk in the range of 1-5 mM. The found effect is a positive technological evidence in terms of cheese making, since it allows varying the content of calcium chloride added to the milk mixture without a threat of significant changes in the undesired proteolytic activity of used milk-clotting enzyme. recombinant chymosin, technological properties, amino acid substitutions, milk-clotting activity, concentration of calcium chloride. The work was performed within the framework of the state task of the Ministry of science and higher education of the Russian Federation (topic number fzmw-2020-0002, "Development of recombinant enzyme producers for cheese making").

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