Ion dehydration controls adsorption at the micellar interface: hydrotropic ions

Lima, Filipe da Silva; Andrade, Mauro; Mortara, Laura; Dias, Luís Gustavo; Cuccovia, Iolanda Midea; Chaimovich, Hernán

doi:10.1039/c7cp05283a

Cited by 11 publications

(22 citation statements)

References 67 publications

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“…Similar behavior was observed in a study of the interaction of micelles with polyatomic counterions with apolar and polar moieties. Experimental results and MD simulations showed that counterions with the same apolar groups but different polar groups resulted in similar ionic affinities for dodecyltrimethylammonium micelles, and the simulations showed that counterion adsorption to the micelles was related with the dehydration of the apolar group of the counterions rather than by the polar group 41 .…”

Section: Discussionmentioning

confidence: 88%

Binding and Flip as Initial Steps for BP-100 Antimicrobial Actions

Park

Franco

Chaimovich

et al. 2019

Sci Rep

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BP100 is a short antimicrobial peptide and can also act as a molecule-carrier into cells. Like with other antimicrobial peptides, the precise mechanism of membrane disruption is not fully understood. Here we use computer simulations to understand, at a molecular level, the initial interaction between BP100 and zwitterionic/negatively charged model membranes. In agreement with experimental results, our simulations showed BP100 folded into an alpha helix when in contact with negatively charged membranes. BP100 binding induced the aggregation of negatively charged lipids on mixed membranes composed of zwitterionic and anionic lipids. The peptide in alpha-helix conformation initially interacts with the membrane via electrostatic interactions between the negatively charged lipids and the positively charged residues of the peptide. At that point the peptide flips, burying the hydrophobic residues into the bilayer highlighting the importance of the hydrophobic effect contribution to the initial interaction of cationic antimicrobial peptides with membranes.

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Section: Discussionmentioning

confidence: 88%

Binding and Flip as Initial Steps for BP-100 Antimicrobial Actions

Park

Franco

Chaimovich

et al. 2019

Sci Rep

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“…Increase of external salt concentration or binding of hydrotropic anions to positively charged micelles of N -hexadecyltrimethylammonium (CTAX, where X is the anion), a surfactant that has the same positively charged group as DPS monomers, produces severe interfacial dehydration and changes in shape of the micelle . An extreme case is exemplified by trifluoromethyl sulfonate (triflate, Tfl), a counterion that binds strongly to cationic micelles of N -dodecyltrimethylammonium (DTAX), produces significant dehydration of the interface, and can induce phase separation. , It is clear, therefore, that for cationic micelles a correlation between specific ion effects in micelles and micellar interfacial hydration is established and even to ion (de)hydration upon adsorption at the micellar interface …”

Section: Introductionmentioning

confidence: 99%

Specific Ion Effects on Zwitterionic Micelles Are Independent of Interfacial Hydration Changes

et al. 2018

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Zwitterionic micelles adsorb anions and several techniques were used to determine the specificity of this interaction. Although at a lower intensity, this adsorption can be compared to those observed in cationic micelles, which showed that interfacial dehydration is a fundamental property for the geometry and size of micelles. Because there is no information on the interfacial hydration of zwitterionic micelles, we used dielectric relaxation spectroscopy (DRS) together with molecular dynamics (MD) simulations to evaluate the importance of surface dehydration promoted by the binding of anions at the micellar interface (sodium bromide, sodium methanesulfonate, sodium trifluoroacetate, and sodium triflate) in N-dodecyl- N, N-dimethyl-3-ammonio-1-propanesulfonate (DPS) micelles. Our results, showing good agreement between DRS and MD simulations, strongly suggest that specific ion effects on zwitterionic micelles are unrelated to global changes in the interfacial hydration and depend on specific interactions of the headgroups with selected anions.

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“…After interaction with the membrane, the AMPs hydrophobic/hydrophilic topological distribution acquires a secondary structure that provides the peptide with a spatial amphipathic character, favoring the interaction with the membrane interface [4,7]. Dehydration of the hydrophobic moieties, and not just the electrostatic components, can determine the bonding selectivity of AMPs to bacterial membranes [10].…”

Section: Introductionmentioning

confidence: 99%

Model Membrane Interactions and Biological Activity of a Naphthalimide-Containing BP100

Gpb¹,

Gkv²,

Ma³

et al. 2021

Preprint

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In a large variety of organisms, antimicrobial peptides (AMPs) are primary defences against pathogens. BP100 (KKLFKKILKYL-NH2), a short, synthetic, and cationic AMP, is active against bacteria and displays low toxicity towards eukaryotic cells. BP100 acquires an α-helical conformation upon interaction with membranes and increases membrane permeability. Despite the volume of information available, the mechanism of action of BP100, the selectivity of its biological effects, and its applications are far from consensual. In this work, we synthesized a fluorescent BP100 analog containing naphthalimide linked to its N-terminal end, Napht-BP100 (Napht-AAKKLFKKILKYL-NH2). The fluorescence properties of naphthalimides, especially their spectral sensitivity to microenvironment changes, are well established, and their biological activities against different types of cells are known. A wide variety of techniques were used to demonstrate that a-helical Napht-BP100 was bound and permeabilized POPC and POPG LUV. Napht-BP100, different from that observed for BP100, was bound to, and permeabilized POPC LUV. With zwitterionic (POPC) and negatively charged (POPG) containing LUVs, membrane surface high peptide/lipid ratios triggered complete disruption of the liposomes in a detergent-like manner. This disruption was driven by charge neutralization, lipid aggregation, and membrane destabilization. Napht-BP100 also interacted with double-stranded DNA, indicating that this peptide could also affect other cellular processes in addition to membrane destabilization. Napht-BP100 showed superior antibacterial activity, increased hemolytic activity compared to BP100, and may constitute an efficient antimicrobial agent for dermatological use. By conjugating BP100 and naphthalimide antimicrobial properties, Napht-BP100 was bound more efficiently to the bacterial membrane and could destabilize the membrane and enter the cell by interacting with its cytoplasm- exposed DNA.

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Ion dehydration controls adsorption at the micellar interface: hydrotropic ions

Cited by 11 publications

References 67 publications

Binding and Flip as Initial Steps for BP-100 Antimicrobial Actions

Binding and Flip as Initial Steps for BP-100 Antimicrobial Actions

Specific Ion Effects on Zwitterionic Micelles Are Independent of Interfacial Hydration Changes

Model Membrane Interactions and Biological Activity of a Naphthalimide-Containing BP100

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