Ribosomal Synthesis of Backbone-Cyclic Peptides Compatible with In Vitro Display

2019 ◽  
Vol 141 (6) ◽  
pp. 2279-2287 ◽  
Author(s):  
Ryo Takatsuji ◽  
Koki Shinbara ◽  
Takayuki Katoh ◽  
Yuki Goto ◽  
Toby Passioura ◽  
...  
Keyword(s):  
Cyclic Peptides ◽  
Backbone Cyclic Peptides

scholarly journals A Limulus Antilipopolysaccharide Factor-Derived Peptide Exhibits a New Immunological Activity with Potential Applicability in Infectious Diseases

2000 ◽  
Vol 7 (4) ◽  
pp. 669-675 ◽  
Author(s):  
Maribel G. Vallespi ◽  
Luis A. Glaria ◽  
Osvaldo Reyes ◽  
Hilda E. Garay ◽  
Joel Ferrero ◽  
...  
Keyword(s):  
Infectious Diseases ◽  
Cyclic Peptides ◽  
Mononuclear Cells ◽  
Therapeutic Potential ◽  
Peritoneal Macrophages ◽  
Induced Response ◽  
No Production ◽  
Human Mononuclear Cells

ABSTRACT Previous studies have shown that cyclic peptides corresponding to residues 35 to 52 of the Limulus antilipopolysaccharide (anti-LPS) factor (LALF) bind and neutralize LPS-mediated in vitro and in vivo activities. Therapeutic approaches based on agents which bind and neutralize LPS activities are particularly attractive because these substances directly block the primary stimulus for the entire proinflammatory cytokine cascade. Here we describe new activities of the LALF31–52 peptide, other than its LPS binding ability. Surprisingly, supernatants from human mononuclear cells stimulated with the LALF peptide are able to induce in vitro antiviral effects on the Hep-2 cell line mediated by gamma interferon (IFN-γ) and IFN-α. Analysis of the effect of LALF31–52 on tumor necrosis factor (TNF) and nitric oxide (NO) production by LPS-stimulated peritoneal macrophages revealed that a pretreatment with the peptide decreased LPS-induced TNF production but did not affect NO generation. This indicates that the LALF peptide modifies the LPS-induced response. In a model in mice with peritoneal fulminating sepsis, LALF31–52 protected the mice when administered prophylactically, and this effect is related to reduced systemic TNF-α levels. This study demonstrates, for the first time, the anti-inflammatory properties of the LALF-derived peptide. These properties widen the spectrum of the therapeutic potential for this LALF-derived peptide and the molecules derived from it. These agents may be useful in the prophylaxis and therapy of viral and bacterial infectious diseases, as well as for septic shock.

scholarly journals Systemic Antibacterial Activity of Novel Synthetic Cyclic Peptides

2005 ◽  
Vol 49 (8) ◽  
pp. 3302-3310 ◽  
Author(s):  
Véronique Dartois ◽  
Jorge Sanchez-Quesada ◽  
Edelmira Cabezas ◽  
Ellen Chi ◽  
Chad Dubbelde ◽  
...  
Keyword(s):  
Cyclic Peptides ◽  
Prolonged Exposure ◽  
Cyclic Peptide ◽  
Present Report ◽  
Bacterial Load ◽  
Pharmacokinetic Profile ◽  
Therapeutic Window ◽  
Infection Model

ABSTRACT Cyclic peptides with an even number of alternating d,l-α-amino acid residues are known to self-assemble into organic nanotubes. Such peptides previously have been shown to be stable upon protease treatment, membrane active, and bactericidal and to exert antimicrobial activity against Staphylococcus aureus and other gram-positive bacteria. The present report describes the in vitro and in vivo pharmacology of selected members of this cyclic peptide family. The intravenous (i.v.) efficacy of six compounds with MICs of less than 12 μg/ml was tested in peritonitis and neutropenic-mouse thigh infection models. Four of the six peptides were efficacious in vivo, with 50% effective doses in the peritonitis model ranging between 4.0 and 6.7 mg/kg against methicillin-sensitive S. aureus (MSSA). In the thigh infection model, the four peptides reduced the bacterial load 2.1 to 3.0 log units following administration of an 8-mg/kg i.v. dose. Activity against methicillin-resistant S. aureus was similar to MSSA. The murine pharmacokinetic profile of each compound was determined following i.v. bolus injection. Interestingly, those compounds with poor efficacy in vivo displayed a significantly lower maximum concentration of the drug in serum and a higher volume of distribution at steady state than compounds with good therapeutic properties. S. aureus was unable to easily develop spontaneous resistance upon prolonged exposure to the peptides at sublethal concentrations, in agreement with the proposed interaction with multiple components of the bacterial membrane canopy. Although additional structure-activity relationship studies are required to improve the therapeutic window of this class of antimicrobial peptides, our results suggest that these amphipathic cyclic d,l-α-peptides have potential for systemic administration and treatment of otherwise antibiotic-resistant infections.

scholarly journals Aggregation of Aβ40/42 chains in the presence of cyclic neuropeptides investigated by molecular dynamics simulations

2021 ◽  
Vol 17 (3) ◽  
pp. e1008771
Author(s):  
Min Wu ◽  
Lyudmyla Dorosh ◽  
Gerold Schmitt-Ulms ◽  
Holger Wille ◽  
Maria Stepanova
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Cyclic Peptides ◽  
Molecular Mechanisms ◽  
Surface Effect ◽  
Early Stage ◽  
Aβ Peptides ◽  
Hydrophobic Residues ◽  
Dynamics Simulations

Alzheimer’s disease is associated with the formation of toxic aggregates of amyloid beta (Aβ) peptides. Despite tremendous efforts, our understanding of the molecular mechanisms of aggregation, as well as cofactors that might influence it, remains incomplete. The small cyclic neuropeptide somatostatin-14 (SST14) was recently found to be the most selectively enriched protein in human frontal lobe extracts that binds Aβ42 aggregates. Furthermore, SST14’s presence was also found to promote the formation of toxic Aβ42 oligomers in vitro. In order to elucidate how SST14 influences the onset of Aβ oligomerization, we performed all-atom molecular dynamics simulations of model mixtures of Aβ42 or Aβ40 peptides with SST14 molecules and analyzed the structure and dynamics of early-stage aggregates. For comparison we also analyzed the aggregation of Aβ42 in the presence of arginine vasopressin (AVP), a different cyclic neuropeptide. We observed the formation of self-assembled aggregates containing the Aβ chains and small cyclic peptides in all mixtures of Aβ42–SST14, Aβ42–AVP, and Aβ40–SST14. The Aβ42–SST14 mixtures were found to develop compact, dynamically stable, but small aggregates with the highest exposure of hydrophobic residues to the solvent. Differences in the morphology and dynamics of aggregates that comprise SST14 or AVP appear to reflect distinct (1) regions of the Aβ chains they interact with; (2) the propensities to engage in hydrogen bonds with Aβ peptides; and (3) solvent exposures of hydrophilic and hydrophobic groups. The presence of SST14 was found to impede aggregation in the Aβ42–SST14 system despite a high hydrophobicity, producing a stronger “sticky surface” effect in the aggregates at the onset of Aβ42–SST14 oligomerization.

scholarly journals A β-Hairpin Epitope as Novel Structural Requirement for Protein Arginine Rhamnosylation

2020 ◽  
Author(s):  
Nathaniel Martin ◽  
Marthe Walvoort ◽  
Liubov Yakovlieva ◽  
Thomas Wood ◽  
Johan Kemmink ◽  
...  
Keyword(s):  
Amino Acid ◽  
Amino Acid Sequence ◽  
Cyclic Peptides ◽  
Protein Glycosylation ◽  
Recognition Sequence ◽  
Structural Requirement ◽  
Amino Acid Sequence Variation ◽  
Substrate Peptide ◽  
Domains Of Life

<p>Protein <i>N</i>-glycosylation is ubiquitously present in all domains of life, and confers a plethora of functions to the protein including increased solubility, protection from degradation, interaction with receptors, and activation for function. For canonical asparagine glycosylation, the recognition sequence that directs glycosylation at specific asparagine residues is well-established. It generally holds for protein glycosylation that the primary amino acid sequence is most important for substrate recognition. Here we reveal that a recently discovered bacterial enzyme called EarP, that transfers rhamnose to a specific arginine residue in its acceptor protein EF-P, specifically recognizes a β-hairpin loop. Notably, while the rhamnosyltransferase activity of EarP is abolished when presented with linear substrate peptide sequences derived from EF-P <i>in vitro</i>, the enzyme readily glycosylates the same sequence when presented in a cyclized β-hairpin mimic containing an l-Pro-d-Pro motif. Additional studies with other substrate-mimicking cyclic peptides revealed that EarP activity is sensitive to the method used to induce cyclization and in some cases is tolerant to amino acid sequence variation. Using detailed NMR approaches, we established that the active peptide substrates all share some degree of β-hairpin formation, and therefore conclude that the β-hairpin epitope is the major determinant of arginine-rhamnosylation by EarP. Our findings add a novel recognition motif to the existing knowledge on substrate specificity of protein glycosylation, and are expected to inform future identifications of rhamnosylation sites in other protein substrates.</p>

scholarly journals An Efficient Method for the In Vitro Production of Azol(in)e-Based Cyclic Peptides

2014 ◽  
Vol 53 (51) ◽  
pp. 14171-14174 ◽  
Author(s):  
Wael E. Houssen ◽  
Andrew F. Bent ◽  
Andrew R. McEwan ◽  
Nathalie Pieiller ◽  
Jioji Tabudravu ◽  
...  
Keyword(s):  
Efficient Method ◽  
Cyclic Peptides ◽  
In Vitro Production ◽  
Vitro Production

scholarly journals Click Conjugation of Boron Dipyrromethene (BODIPY) Fluorophores to EGFR-Targeting Linear and Cyclic Peptides

Molecules ◽  
2021 ◽  
Vol 26 (3) ◽  
pp. 593 ◽  
Author(s):  
Tyrslai M. Williams ◽  
Nichole E. M. Kaufman ◽  
Zehua Zhou ◽  
Sitanshu S. Singh ◽  
Seetharama D. Jois ◽  
...  
Keyword(s):  
Cyclic Peptides ◽  
Cyclic Peptide ◽  
Click Reaction ◽  
Cycloaddition Reaction ◽  
Growth Factor Receptor ◽  
Extracellular Domain ◽  
Binding Studies ◽  
Peptide Conjugates ◽  
Human Carcinoma

Through a simple 1,3-cycloaddition reaction, three BODIPY-peptide conjugates that target the extracellular domain of the epidermal growth factor receptor (EGFR) were prepared and their ability for binding to EGFR was investigated. The peptide ligands K(N3)LARLLT and its cyclic analog cyclo(K(N3)larllt, previously shown to have high affinity for binding to the extracellular domain of EGFR, were conjugated to alkynyl-functionalized BODIPY dyes 1 and 2 via a copper-catalyzed click reaction. This reaction produced conjugates 3, 4, and 5 in high yields (70–82%). In vitro studies using human carcinoma HEp2 cells that overexpress EGFR demonstrated high cellular uptake, particularly for the cyclic peptide conjugate 5, and low cytotoxicity in light (~1 J·cm−2) and darkness. Surface plasmon resonance (SPR) results show binding affinity of the three BODIPY-peptide conjugates for EGFR, particularly for 5 bearing the cyclic peptide. Competitive binding studies using three cell lines with different expressions of EGFR show that 5 binds specifically to EGFR-overexpressing colon cancer cells. Among the three conjugates, 5 bearing the cyclic peptide exhibited the highest affinity for binding to the EGFR protein.

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