Mechanism of Membrane Activity of the Antibiotic Trichogin GA IV: A Two-State Transition Controlled by Peptide Concentration

Meisina, Claudia; Stella, Lorenzo; Venanzi, Mariano; Formaggio, Fernando; Toniolo, Claudio; Pispisa, B.

doi:10.1529/biophysj.104.056077

Cited by 66 publications

(74 citation statements)

References 59 publications

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“…Unfortunately, we cannot follow this region by PELDOR due to its limitation to give a reliable signal because of the small phase relaxation times at higher local spin concentrations. For this reason we are not in the position to detect peptide aggregation as it has been done by luminescence quenching of a fluorescently labeled trichogin analog in ePC liposomes consisting of 50 mol% cholesterol [7].…”

Section: The Mutual Distribution Of Trichogin Molecules In Epc Membranesmentioning

confidence: 99%

Membrane-peptide interaction studied by PELDOR and CW ESR: Peptide conformations and cholesterol effect on the spatial peptide distribution in the membrane

et al. 2005

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Pulsed electron-electron double resonance (PELDOR) combined with continuous-wave electron paramagnetic resonance was used to study inter- and intramolecular dipole-dipole interactions between spin labels for spin-labeled analogs of trichogin GA IV bound to multilamellar membranes of egg L-alpha-phosphatidylcholine (ePC) and in ePC membranes containing cholesterol. All samples were frozen to 77 K. For mono-labeled peptide concentrations in lipid over the range between 0.5 to 2.2 mol%, it is shown that in these membranes trichogin molecules are distributed homogeneously and are likely to be located on or near the inner and outer membrane surfaces. Addition of cholesterol to a final concentration of 16.5 mol% leads to an increase of the local concentration of trichogin molecules in the membranes. For the double-labeled trichogin, a distribution of the intramolecular distance between the two spin labels was observed. The distribution function is characterized by two main maxima located at distances of 1.3 and 1.8 nm. The distance of 1.3 nm is close to that expected for the alpha-helix structure of the peptide chain. The distance of 1.8 nm corresponds to a mixed structure in which a 3(10) helix is combined with a set of even more elongated conformations

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Section: The Mutual Distribution Of Trichogin Molecules In Epc Membranesmentioning

confidence: 99%

Membrane-peptide interaction studied by PELDOR and CW ESR: Peptide conformations and cholesterol effect on the spatial peptide distribution in the membrane

et al. 2005

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“…This conclusion raises a further question as to whether Alm, when added to preformed vesicles, remains on the outer membrane surface only, or if it is able to translocate across the bilayer so that some peptide molecules expose their C-termini to the water phase inside the liposomes. To clarify this issue, an assay based on Fçrsters fluorescence resonance-energy transfer (FRET) was performed [15]. An energy-transfer acceptor for the labeled Alm analogues was introduced in the membranes as a fluorescent lipid, i.e., 1-palmitoyl-2-{6-[(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino]caproyl}-l-a-phosphatidylcholine (C6-NBD-PC).…”

mentioning

confidence: 99%

Alamethicin Interaction with Lipid Membranes: A Spectroscopic Study on Synthetic Analogues

Stella

Burattini

Meisina

et al. 2007

Chemistry & Biodiversity

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Alamethicin (Alm) is one of the most extensively studied membrane-active antibiotic peptides, but several aspects of its mechanism of action are still under debate. In this study, synthetic analogues of natural Alm F50/5 (Alm-N), labeled with a 9H-fluoren-9-yl group at the N- (F-Alm) or C-terminus (Alm-F), were employed to investigate the position and orientation of this peptide in the membrane environment. Depth-dependent fluorescence quenching and polarized ATR-FT-IR experiments demonstrated that, in the absence of a transmembrane potential, Alm inserts its N-terminus into the membrane, while the C-terminus is exposed to the outer aqueous phase. We also found that the peptaibol populates different orientations with respect to the membrane normal. Furthermore, fluorescence resonance-energy transfer (FRET) indicated that no peptide translocation to the inner leaflet of lipid bilayers occurs. The mechanism of action of Alm is discussed on the basis of these findings. Two other Alm analogues, Alm-P and Alm-S, were exploited to investigate the role of specific Alm residues in terms of membrane-perturbing activity. Substitution of two or three Gln (E) residues (the only polar amino acids in the alamethicin sequence) by gamma-methyl glutamate (Glu(OMe)) residues induced marked variations in the aggregation and partition behaviors of the peptaibols, which, in turn, modulate their membrane activity. In particular, substitution of Gln(18) and Gln(19) caused a six-fold increase in membrane-perturbing activity, thus demonstrating that these residues are not essential for the stabilization of Alm pores.

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“…This transition is absent for H-18 and cycL-25. According to the ''two-state'' model (11,43,44), the disturbance of the lipid membrane by peptides is attained through three sequential stages: interfacial binding in an unfolded state followed by the ordered secondary structure formation and finally by the insertion of ordered units into the lipid bilayer. Because the entropy decreases when ordered structure is formed, the penetration is free energy favored only when the entropy penalty is sufficiently compensated by the hydrogen bonding in helix formation (10,43).…”

Section: Discussionmentioning

confidence: 99%

Antitumor activity of a membrane lytic peptide cyclized with a linker sensitive to membrane type 1-matrix metalloproteinase

Zhong

Chau²

2008

Molecular Cancer Therapeutics

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Membrane lytic peptides are a novel class of anticancer agents that have the potential to overcome drug resistance. The limited selectivity against cancer cells, however, presents a major hurdle for the application. We aim to exploit the proteolytic activity of tumor-associated matrix metalloproteinases (MMP) to mediate the cytotoxicity of these peptides. We designed a membrane lytic peptide cyclized with a linker cleavable by membrane type 1-MMP (MT1-MMP). We showed that the cyclic peptide could be restored to the linear state on MT1-MMP digestion, and it preferentially killed MMP-overexpressing cells above a threshold concentration. Circular dichroism indicated that cyclization resulted in a more rigid structure, making it more difficult for the lytic peptide to transit from random coil to A-helix in a membrane-mimicking environment. Selective membrane activity of the cyclic peptide was shown by comparing cytotoxicity results on RBC and two human breast cancer cell lines of different malignancy and MT1-MMP expression: highly invasive MDA-MB-435 and noninvasive MCF-7. Above a concentration of 5 Mmol/L, suppressed activity to MCF-7 and RBC was observed, whereas the toxicity against MDA-MB-435 was maintained. MMP inhibition experiments further showed that the membrane-lysing activity was enzyme dependent. [Mol Cancer Ther 2008;7(9):2933 -40]

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Mechanism of Membrane Activity of the Antibiotic Trichogin GA IV: A Two-State Transition Controlled by Peptide Concentration

Cited by 66 publications

References 59 publications

Membrane-peptide interaction studied by PELDOR and CW ESR: Peptide conformations and cholesterol effect on the spatial peptide distribution in the membrane

Membrane-peptide interaction studied by PELDOR and CW ESR: Peptide conformations and cholesterol effect on the spatial peptide distribution in the membrane

Alamethicin Interaction with Lipid Membranes: A Spectroscopic Study on Synthetic Analogues

Antitumor activity of a membrane lytic peptide cyclized with a linker sensitive to membrane type 1-matrix metalloproteinase

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