Polymeric monolayers and liposomes as models for biomembranes

Bader, Hubert; Dorn, Klaus; Hupfer, B.; Ringsdorf, Helmut

doi:10.1007/3-540-13483-2_1

Cited by 155 publications

(68 citation statements)

References 98 publications

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“…Differentiating ligand binding events with bacterial membrane lipidic moieties and membranebound proteins is not obvious. This issue was addressed by analyzing model systems: phosphatidylcholine liposomes, a widely spread model for phospholipidic biomembranes, 12 and HSA (human serum albumin) as a model for the proteic transport systems due to the outstanding ability of HSA to bind reversibly to an incredible variety of ligands. Figure 2A.…”

Section: Resultsmentioning

confidence: 99%

STD NMR spectroscopy: a case study of fosfomycin binding interactions in living bacterial cells

Milagre¹,

Cabeça²,

Martins³

et al. 2011

J. Braz. Chem. Soc.

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O experimento de RMN STD (saturation transfer difference) foi empregado com sucesso na observação das interações de ligação entre fosfomicina e cepas bacterianas resistentes e não resistentes à fosfomicina, diretamente em suspensões celulares vivas sem necessidade de marcação isotópica do ligante ou receptor.A saturation transfer difference (STD) NMR experiment was successfully employed to observe the binding interactions of fosfomycin resistant and non-resistant bacterial strains using living cell suspensions, without the need for isotopic labelling of the ligand or receptor. Keywords: STD NMR in living bacterial cells, membrane-bound proteins, ligand-target interactions, fosfomycin, liposomes IntroductionSaturation transfer difference (STD) is a 1 H NMR technique widely used to investigate ligand (small molecules) and macromolecular (proteins and peptides, 1 carbohydrates, 2 lipids 3 and nucleic acids 4 ) interactions. This tool (a STD experiment) is appropriate to probe biological binding events at the molecular level 5 and is based on the nuclear Overhauser effect (nOe) transfer from the macromolecule to the ligand. It consists of applying a selective radio frequency pulse to the macromolecule at a resonance where no ligand signals are present. The magnetization is transferred to the entire macromolecule via intra-molecular spin diffusion and then this saturation is transferred intermolecularly to bound ligands and detected in the free-ligand solution. The ligand's hydrogen most tightly bound to the macromolecule will receive the most intense magnetization-transfer and the amplitude of these signals will change accordingly to the nOe effects. 5,6 Therefore, the degree of nOe effects reflects the proximity of these protons to the macromolecule, allowing direct observation of the ligand moiety involved in the macromolecule-ligand interaction. Among the vast literature covering biological interactions observed by STD NMR spectroscopy there are few examples in which the detection of those binding processes occurs directly in whole living cells. 7 The information obtained in such investigation is rather important, especially when studying ligand-membrane-bound protein interactions as most biologically relevant proteins are membrane-bound 8 and are often difficult to deal with as they lose their structures and functionality when removed from their natural membrane environment.Herein we show the use of STD NMR to obtain information about direct drug transport into a cell of living bacterial cell suspensions. As an example we used the well-known fosfomycin uptake by cells and the relationship between fosfomycin resistance in bacterial strains.9 Fosfomycin or phosphonomycin, [(1R,2S)-1,2-epoxypropylphosphonic acid)] is a broad spectrum antibiotic against Gram-negative and Grampositive bacteria and has become the first choice for the treatment of certain infections, especially those caused by cephalosporin and penicillin-resistant Streptococcus pneumoniae and, methicillin-and vancomycin-resistant Staphylococcus aureus...

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Section: Resultsmentioning

confidence: 99%

STD NMR spectroscopy: a case study of fosfomycin binding interactions in living bacterial cells

Milagre¹,

Cabeça²,

Martins³

et al. 2011

J. Braz. Chem. Soc.

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“…Main chain spacers diminish the density of the functional groups at the backbone, whereas side-chain spacers provide additional space by separating the functional groups from the backbone. The spacer concept was particularly successful for some self-organizing polymers such as polymeric liquid crystals [8,87,236,237] and polymeric lipids [7,8,13,56,[232][233][234][235]. It has proven useful for poly soaps as well, making any geometry accessible [167,168].…”

Section: The Spacer Conceptmentioning

confidence: 99%

“…The backbone must neither interfere with an efficient packing nor with the correct orientation of the side chains. Thus, extensively long spacers are needed to achieve water-solubility [100, 102, 157], much longer than the spacer group equivalent of six to twelve carbons which are sufficient for polymeric liquid crystals or for polymeric lipids [7,8,87,[232][233][234][235][236][237]. The "head type" polymers having only standard tri-to octaethyleneoxide spacers (Table 5) …”

Section: The Spacer Conceptmentioning

confidence: 99%

“…They have attracted much attention in recent years because of their resemblance to biological systems as well as their strong tendency for self-organization in aqueous environments due to the hydrophobic effect [1][2][3], creating plentiful superstructures [4,5] on the intermediate level between molecular and macroscopic structures ("mesoscopic scale" [6]). In particular, the subgroups of polymeric lipids and lipid analogs have been investigated in detail with respect to their self-organization in insoluble monolayers, in (Langmuir-Blodgett) multilayers, in vesicles and in myelin structures, thus providing general concepts for their understanding [7][8][9][10][11][12][13][14][15][16][17].…”

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Molecular concepts, self-organisation and properties of polysoaps

Laschewsky

Polysoaps/Stabilizers/Nitrogen-15 NMR

223

126

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The article reviews water-soluble polymers characterized by surfactant side chains, and related amphiphilic polymers. Various synthetic approaches are presented, and rules for useful molecular architectures are given. Models for the self-organization of such polymers in water are presented comparing them with the micellization of low molecular weight surfactants. Highlighting key properties of aqueous polysoap solutions such as viscosity, surface tension and solubilization power, some structure-property relationships are established. Further, the formation of mesophases and of superstructures in bulk is addressed. Finally, the functionalization of polysoaps, and potential applications are discussed.

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“…[29,30] Eine frühe Anwendung des biomimetischen Konzepts in der organischen Materialwissenschaft waren die von Ringsdorf in den 80er Jahren entworfenen künstlichen Liposomen. [31,32] Wenngleich schon mehrere Bücher die Fortschritte auf diesem Gebiet behandelt haben, verfügt die biomimetische Materialwissenschaft auch weiterhin über enorme Entwicklungsmçglichkeiten. Zurzeit besteht enormes Interesse an diesem Forschungsgebiet, bedingt durch das Zusammentreffen dreier Triebkräfte der physikalisch-biologischen Forschung: 1) die verbreitete Erkenntnis, dass ein fachübergreifender Forschungsansatz rasche Fortschritte liefern kann, 2) das exponentielle Wachstum bei der Leistungsfähigkeit analytischer Methoden und der Rechenleistung von Computern, welche die Aufklärung der strukturellen und molekularen Organisation natürlicher Materialien bis in die kleinste Dimension gestatten, und 3) die Verbesserung chemischer und biologischer Synthesemethoden, die einen mühelosen Aufbau naturnaher Modellsysteme sowie hochleistungsfähiger biologisch inspirierter Polymere ermçglichen.…”

Section: Einführung In Die Biomimikryunclassified

Modulares Design in natürlichen und biomimetischen elastischen Materialien

Kushner

Guan

2011

Angewandte Chemie

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Unter Verwendung der zwanzig natürlichen Aminosäuren als Grundbausteine haben biologische Systeme während der Jahrmillionen unter evolutionärem und umweltbedingtem Druck stabile und leichte Peptid‐basierte Materialien entwickelt. Diese Materialien übertreffen ihre synthetischen Gegenstücke in mehrfacher Hinsicht: 1) Multifunktionalität/Abstimmbarkeit, 2) Anpassungsfähigkeit/Reizempfindlichkeit, 3) Synthese und Weiterverarbeitung bei Umgebungsbedingungen in wässrigem Medium und 4) Wiederverwertung und biologische Abbaubarkeit. Diese besonderen Eigenschaften können durch eine “Bottom‐up”‐Synthese und die hierarchische Organisation auf verschiedenen Längenskalen erreicht werden. Das Arbeitsgebiet der “Biomimikry” beschäftigt sich damit, die Gestaltungsprinzipien natürlicher Materialien und deren molekulare Bausteine aufzuklären und zu kopieren. Hier beschreiben wir, was bereits über Struktur und molekulare Mechanismen natürlicher polymerer Materialien erforscht wurde, sowie den Fortschritt in Richtung synthetischer “Nachbildungen” dieser bemerkenswerten Systeme.

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Polymeric monolayers and liposomes as models for biomembranes

Cited by 155 publications

References 98 publications

STD NMR spectroscopy: a case study of fosfomycin binding interactions in living bacterial cells

STD NMR spectroscopy: a case study of fosfomycin binding interactions in living bacterial cells

Molecular concepts, self-organisation and properties of polysoaps

Modulares Design in natürlichen und biomimetischen elastischen Materialien

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