scholarly journals Novel Cyclic Lipopeptide Antibiotics: Effects of Acyl Chain Length and Position

2020 ◽  
Vol 21 (16) ◽  
pp. 5829 ◽  
Author(s):  
Signe Kaustrup Jensen ◽  
Thomas T. Thomsen ◽  
Alberto Oddo ◽  
Henrik Franzyk ◽  
Anders Løbner-Olesen ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Fatty Acid ◽  
Chain Length ◽  
Peptide Synthesis ◽  
Hemolytic Activity ◽  
Cyclic Peptide ◽  
Solid Phase ◽  
Solid Phase Peptide Synthesis ◽  
Resistant Bacteria ◽  
Cyclic Lipopeptide

Multidrug-resistant bacteria are a global health problem. One of the last-resort antibiotics against Gram-negative bacteria is the cyclic lipopeptide colistin, displaying a flexible linker with a fatty acid moiety. The aim of the present project was to investigate the effect on antimicrobial activity of introducing fatty acid moieties of different lengths and in different positions in a cyclic peptide, S3(B), containing a flexible linker. The lipidated analogues of S3(B) were synthesized by 9-fluorenylmethoxycarbonyl (Fmoc) solid-phase peptide synthesis. Following assembly of the linear peptide by Fmoc solid-phase peptide synthesis, on-resin head-to-tail cyclization and fatty acid acylation were performed. The antimicrobial activity was determined against the ESKAPE pathogens, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Escherichia coli. Furthermore, hemolytic activity was determined against human erythrocytes. A total of 18 cyclic lipopeptides were synthesized and characterized. It was found that introduction of fatty acids in positions next to the flexible linker was more strongly linked to antimicrobial activity. The fatty acid length altered the overall hydrophobicity, which was the driving force for both high antimicrobial and hemolytic activity. Peptides became highly hemolytic when carbon-chain length exceeded 10 (i.e., C10), overlapping with the optimum for antimicrobial activity (i.e., C8–C12). The most promising candidate (C8)5 showed antimicrobial activity corresponding to that of S3(B), but with an improved hemolytic profile. Finally, (C8)5 was further investigated in a time-kill experiment.

A general approach to the quantitation of synthetic efficiency in solid-phase peptide synthesis as a function of chain length

1984 ◽  
Vol 106 (25) ◽  
pp. 7845-7850 ◽  
Author(s):  
Virender K. Sarin ◽  
Stephen B. H. Kent ◽  
Alexander R. Mitchell ◽  
R. B. Merrifield
Keyword(s):  
Chain Length ◽  
Peptide Synthesis ◽  
Solid Phase ◽  
Solid Phase Peptide Synthesis ◽  
Synthetic Efficiency

scholarly journals Pyrrole-Mediated Peptide Cyclization Identified through Genetically Reprogrammed Peptide Synthesis

Biomedicines ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 99 ◽  
Author(s):  
Klaas Decoene ◽  
Willem Vannecke ◽  
Toby Passioura ◽  
Hiroaki Suga ◽  
Annemieke Madder
Keyword(s):  
Peptide Synthesis ◽  
Cyclic Peptide ◽  
Solid Phase ◽  
Solid Phase Peptide Synthesis ◽  
Screening Method ◽  
In Vitro Translation ◽  
Side Chain ◽  
One Pot ◽  
Depth Analysis

Flexible in vitro translation (FIT) was used as a screening method to uncover a new methodology for peptide constraining based on the attack of a nucleophilic side-chain functionality onto an oxidized furylalanine side chain. A set of template peptides, each containing furylalanine as furan-modified amino acid and a nucleophilic residue (Cys, His, Lys, Arg, Ser, or Tyr), was produced through FIT. The translation mixtures were treated with N-bromosuccinimide (NBS) to achieve selective furan oxidation and subsequent MALDI analysis demonstrated Lys and Ser as promising residues for cyclisation. Solid-phase peptide synthesis (SPPS) was used to synthesize suitable amounts of material for further in-depth analysis and characterisation. It was found that in the case of the peptide containing lysine next to a furylalanine residue, a one-pot oxidation and reduction reaction leads to the generation of a cyclic peptide featuring a pyrrole moiety as cyclisation motif, resulting from the attack of the lysine side chain onto the oxidized furylalanine side chain. Structural evidence was provided via NMR and the generality of the methodology was explored. We hereby expand the scope of our previously developed furan-based peptide labeling and crosslinking strategy.

scholarly journals Effects of Dimerization on the Structure and Biological Activity of Antimicrobial Peptide Ctx-Ha

2012 ◽  
Vol 56 (6) ◽  
pp. 3004-3010 ◽  
Author(s):  
E. N. Lorenzón ◽  
G. F. Cespedes ◽  
E. F. Vicente ◽  
L. G. Nogueira ◽  
T. M. Bauab ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Biological Activity ◽  
Antimicrobial Peptide ◽  
Hemolytic Activity ◽  
Pore Diameter ◽  
Solid Phase ◽  
Biological Activities ◽  
Solid Phase Peptide Synthesis ◽  
Activity Assay ◽  
Growth Of Bacteria

ABSTRACTIt is well known that cationic antimicrobial peptides (cAMPs) are potential microbicidal agents for the increasing problem of antimicrobial resistance. However, the physicochemical properties of each peptide need to be optimized for clinical use. To evaluate the effects of dimerization on the structure and biological activity of the antimicrobial peptide Ctx-Ha, we have synthesized the monomeric and three dimeric (Lys-branched) forms of the Ctx-Ha peptide by solid-phase peptide synthesis using a combination of 9-fluorenylmethyloxycarbonyl (Fmoc) andt-butoxycarbonyl (Boc) chemical approaches. The antimicrobial activity assay showed that dimerization decreases the ability of the peptide to inhibit growth of bacteria or fungi; however, the dimeric analogs displayed a higher level of bactericidal activity. In addition, a dramatic increase (50 times) in hemolytic activity was achieved with these analogs. Permeabilization studies showed that the rate of carboxyfluorescein release was higher for the dimeric peptides than for the monomeric peptide, especially in vesicles that contained sphingomyelin. Despite different biological activities, the secondary structure and pore diameter were not significantly altered by dimerization. In contrast to the case for other dimeric cAMPs, we have shown that dimerization selectively decreases the antimicrobial activity of this peptide and increases the hemolytic activity. The results also show that the interaction between dimeric peptides and the cell wall could be responsible for the decrease of the antimicrobial activity of these peptides.

scholarly journals Recyclable hypervalent-iodine-mediated solid-phase peptide synthesis and cyclic peptide synthesis

2018 ◽  
Vol 14 ◽  
pp. 1112-1119 ◽  
Author(s):  
Dan Liu ◽  
Ya-Li Guo ◽  
Jin Qu ◽  
Chi Zhang
Keyword(s):  
Peptide Synthesis ◽  
Cyclic Peptide ◽  
Solid Phase ◽  
Biological Activities ◽  
Solid Phase Peptide Synthesis ◽  
Coupling Reaction ◽  
Hypervalent Iodine ◽  
Peptide Coupling ◽  
Cyclic Peptide Synthesis ◽  
Cyclic Heptapeptide

The system of the hypervalent iodine(III) reagent FPID and (4-MeOC6H4)3P was successfully applied to solid-phase peptide synthesis and cyclic peptide synthesis. Four peptides with biological activities were synthesized through SPPS and the bioactive cyclic heptapeptide pseudostellarin D was obtained via solution-phase peptide synthesis. It is worth noting that FPID can be readily regenerated after the peptide coupling reaction.

scholarly journals Synthesis of novel sulfide-based cyclic peptidomimetic analogues to solonamides

2019 ◽  
Vol 15 ◽  
pp. 2544-2551
Author(s):  
José Brango-Vanegas ◽  
Luan A Martinho ◽  
Lucinda J Bessa ◽  
Andreanne G Vasconcelos ◽  
Alexandra Plácido ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Quorum Sensing ◽  
Peptide Synthesis ◽  
Hemolytic Activity ◽  
Solid Phase ◽  
Human Fibroblasts ◽  
Solid Phase Peptide Synthesis ◽  
Bacterial Quorum Sensing ◽  
Bacterial Quorum ◽  
The One

Eight new sulfide-based cyclic peptidomimetic analogues of solonamides A and B have been synthesized via solid-phase peptide synthesis and SN2’ reaction on a Morita–Baylis–Hillman (MBH) residue introduced at the N-terminal of a tetrapeptide. This last step takes advantage of the electrophilic feature of the MBH residue and represents a new cyclization strategy occurring. The analogues were prepared in moderate overall yields and did not show toxic effects on Staphylococcus aureus growth and were not toxic to human fibroblasts. Two of them inhibited the hemolytic activity of S. aureus, suggesting an interfering action in the bacterial quorum sensing similar to the one already reported for solonamides.

scholarly journals Vancomycin-Lipopeptide Conjugates with High Antimicrobial Activity on Vancomycin-Resistant Enterococci

2020 ◽  
Vol 13 (6) ◽  
pp. 110 ◽  
Author(s):  
Eric Mühlberg ◽  
Florian Umstätter ◽  
Cornelius Domhan ◽  
Tobias Hertlein ◽  
Knut Ohlsen ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Fatty Acid ◽  
Chain Length ◽  
Structural Modification ◽  
Multidrug Resistant ◽  
Resistant Bacteria ◽  
Multidrug Resistant Bacteria ◽  
Vancomycin Resistant Enterococci ◽  
Vancomycin Resistant

Multidrug-resistant bacteria represent one of the most important health care problems worldwide. While there are numerous drugs available for standard therapy, there are only a few compounds capable of serving as a last resort for severe infections. Therefore, approaches to control multidrug-resistant bacteria must be implemented. Here, a strategy of reactivating the established glycopeptide antibiotic vancomycin by structural modification with polycationic peptides and subsequent fatty acid conjugation to overcome the resistance of multidrug-resistant bacteria was followed. This study especially focuses on the structure–activity relationship, depending on the modification site and fatty acid chain length. The synthesized conjugates showed high antimicrobial potential on vancomycin-resistant enterococci. We were able to demonstrate that the antimicrobial activity of the vancomycin-lipopeptide conjugates depends on the chain length of the attached fatty acid. All conjugates showed good cytocompatibility in vitro and in vivo. Radiolabeling enabled the in vivo determination of pharmacokinetics in Wistar rats by molecular imaging and biodistribution studies. An improved biodistribution profile in comparison to unmodified vancomycin was observed. While vancomycin is rapidly excreted by the kidneys, the most potent conjugate shows a hepatobiliary excretion profile. In conclusion, these results demonstrate the potential of the structural modification of already established antibiotics to provide highly active compounds for tackling multidrug-resistant bacteria.

A Strategy for Thioamide Incorporation During Fmoc Solid-Phase Peptide Synthesis with Robust Stereochemical Integrity

2019 ◽  
Author(s):  
luis camacho III ◽  
Bryan J. Lampkin ◽  
Brett VanVeller
Keyword(s):  
Amino Acid ◽  
Functional Groups ◽  
Peptide Synthesis ◽  
Solid Phase ◽  
Solid Phase Peptide Synthesis ◽  
Side Chains ◽  
Amino Acid Side Chains ◽  
Peptide Elongation

We describe a method to protect the sensitive stereochemistry of the thioamide—in analogy to the protection of the functional groups of amino acid side chains—in order to preserve the thioamide moiety during peptide elongation.<br>

Analytical Methods for Solid Phase Peptide Synthesis

2004 ◽  
Vol 8 (4) ◽  
pp. 291-301 ◽  
Author(s):  
Giuseppina Sabatino ◽  
Mario Chelli ◽  
Alberto Brandi ◽  
Anna Papini
Keyword(s):  
Peptide Synthesis ◽  
Analytical Methods ◽  
Solid Phase ◽  
Solid Phase Peptide Synthesis
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