Amphipathic cyclooctapeptides: interactions with detergent micelles and metal ions

Gates, William D.; Rostas, Jack W.; Kakati, Bobby; Ngu-Schwemlein, Maria

doi:10.1016/j.molstruc.2004.07.031

Cited by 7 publications

(7 citation statements)

References 21 publications

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“…CPs 1, 2, and 10 were prepared as described previously. [20,37,38] CP 11 was prepared as described for CP 10, [20] except that deprotections of the amino acid side chain protecting groups were carried out with a solution of TFA/H Purification and Characterization of CP 11 CP 11 was prepared by microwave-assisted solid phase peptide synthesis as previously reported for similar peptides. [20] The purity of the crude peptide was 75 % by HPLC.…”

Section: Resultsmentioning

confidence: 99%

In Vitro Synergy Between Some Cationic Amphipathic Cyclooctapeptides and Antibiotics

et al. 2015

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The antimicrobial activities of some cationic amphipathic cyclooctapeptides in combination with select antibiotics are investigated. Accordingly, cyclooctapeptides (CPs 1-11) derived from the sequence cyclo[Leu-D-Leu-Leu-D-Leu-Lys-DLys-Lys-D-Lys] were tested against Escherichia coli and Staphylococcus aureus. Synergistic effects were evaluated in combination with tetracycline, chloramphenicol, oflaxacin, rifampicin, colistin, clindamycin, and vancomycin by the checkerboard titration assay. The results show that these cyclooctapeptides are fast acting bactericidals and are comparable to the related a-helical peptides in their activities. Significantly, some of these cyclooctapeptides exert selective synergistic effects in combination with the bacteriostatic tetracycline against S. aureus; a greater than 4-fold decrease in the minimum inhibition concentration was observed. Their synergism with the other evaluated antibiotics was generally partial or additive. Cationic amphipathic cyclooctapeptides in combination with some antibiotics could offer a possible solution to the increasing antimicrobial resistance predicament.

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Section: Resultsmentioning

confidence: 99%

In Vitro Synergy Between Some Cationic Amphipathic Cyclooctapeptides and Antibiotics

et al. 2015

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“…[16][17][18][19][20][21][22] Due to various of complex sites in peptide monomer including the nitrogen atom at the N-terminus, the carboxylate group at the C-terminus, and the oxygen or nitrogen atoms presenting in the backbone chain, it is difficult to determine which complex site is for sodium binding. The site is a competitive complexation determined by the particular solvent condition.…”

Section: Discussionmentioning

confidence: 99%

Investigation on structure and properties of a novel designed peptide

et al. 2009

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Although the existing design principle of full-sequence ionic complement is convenient for the development of peptides, it greatly constrains the exploration of peptides with other possible assembly mechanisms and different yet essential functions. Herein, a novel designed half-sequence ionic complementary peptide (referred to as P9), AC-Pro-Ser-Phe-Asn-Phe-Lys-Phe-Glu-Pro-NH 2 , is reported. When transferred from pure water to sodium chloride solution, P9 underwent a dramatic morphological transformation from globular aggregations to nanofibers. Moreover, the rheological experiment showed that the P9 could form a hydrogel with a storage modulus of about 30 Pa even at very low peptide concentration (0.5% (wt/vol)). The P9 hydrogel formed in salt solution could recover in a period of about 1,800 sec, which is faster than that in the pure water. The data suggested that the half-sequence, ionic complementary peptide might be worthy of further research for its special properties.

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“…These metal ions are widely used in industry, and their well‐known hazard to human health necessitates a sensitive detection system for their presence in environmental and biological samples. Although the design of chemical sensors for such metal ions has been reported (1–4), we are especially interested in developing cyclopeptide‐based motifs for selective metal‐ion binding and sensing (5,6). Fluorophore‐tagged peptide macrocycles are structurally attractive for a number of reasons, such as: (a) macrocyclic ligands form complexes that are generally thermodynamically and kinetically more stable than their acyclic analogs, (b) the peptide macrocyclic framework can be readily tailored for selective interaction with certain metal ions according to their size, (c) cyclopeptides can adopt secondary and tertiary structures to enable strategic positioning of functional groups, which are readily available from the repertoire of natural and synthetic amino acids, for enhancing metal‐ion binding and to accommodate the coordination positions of the metal ion concerned, (d) appropriate positioning of select types of fluorophores (7,8) in the cyclopeptide allows for a rapid, convenient, and highly sensitive signaling (9) of the peptide–metal ion interactions.…”

Section: Introductionmentioning

confidence: 99%

“…These metal ions are widely used in industry, and their wellknown hazard to human health necessitates a sensitive detection system for their presence in environmental and biological samples. Although the design of chemical sensors for such metal ions has been reported (1)(2)(3)(4), we are especially interested in developing cyclopeptide-based motifs for selective metal-ion binding and sensing (5,6).…”

Section: Introductionmentioning

confidence: 99%

Interactions of an acidic cyclooctapeptide with metal ions: microcalorimetric and fluorescence analyses

Ngu-Schwemlein

Butko

Cook

et al. 2005

The Journal of Peptide Research

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The metal‐ion binding preferences of an acidic amphipathic cyclopeptide, cyclo[d‐Leu‐Leu‐d‐Leu‐Trp‐(d‐Glu‐Glu)2] (CP), was studied by isothermal titration calorimetry and steady‐state fluorescence spectroscopy. CP adopted a partial beta structure, and variable temperature circular dichroism showed small secondary structural changes over the temperature range from 5 °C to 95 °C. The peptide did not bind alkali or alkaline earth metal ions but exhibited selectivity for some divalent transition metal ions (with association constants KCu2+ 4.5 × 104 m−1, KZn2+ 1.6 × 105 m−1, KCd2+ 1.3 × 104 m−1, KHg2+ (1) 2.2 × 106 m−1, and KHg2+ (2) 6.5 × 103 m−1), for Pb2+ (2.0 × 105 m−1), and a trivalent Group III metal, Al3+ (1.6 × 105 m−1). The thermodynamic data show that the interaction between CP and these metal ions are spontaneous and entropically driven. A large range of binding enthalpies coupled with a smaller range of binding free energies of CP for these metal ions indicate an entropy–enthalpy compensation dependent on the ionic size of participating metal ions. The interaction of Pb2+, Hg2+, and Cu2+ with CP in aqueous solution specifically modulates the fluorescence emission properties of CP. The results of this study show that CP exhibits selectivity in metal‐ion binding, which is reflected in its fluorescence spectra. The observed trends can be useful for the design of heavy‐metal sensors based on fluorophore‐tagged acidic cyclopeptides.

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Amphipathic cyclooctapeptides: interactions with detergent micelles and metal ions

Cited by 7 publications

References 21 publications

In Vitro Synergy Between Some Cationic Amphipathic Cyclooctapeptides and Antibiotics

In Vitro Synergy Between Some Cationic Amphipathic Cyclooctapeptides and Antibiotics

Investigation on structure and properties of a novel designed peptide

Interactions of an acidic cyclooctapeptide with metal ions: microcalorimetric and fluorescence analyses

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