References of "Crowet, Jean-Marc"
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See detailMolecular dynamics study of micelle proeprties according to their size
Lebecque, Simon ULg; Crowet, Jean-Marc ULg; Nasir, Mehmet Nail ULg et al

in Journal of Molecular Graphics and Modelling (2017)

Surfactants are molecules able to spontaneously self-assemble to form aggregates with well-defined properties, such as spherical micelles, planar bilayers, cylindrical micelles or vesicles. Micelles have ... [more ▼]

Surfactants are molecules able to spontaneously self-assemble to form aggregates with well-defined properties, such as spherical micelles, planar bilayers, cylindrical micelles or vesicles. Micelles have notably several applications in many domains, such as drug delivery or membrane protein solubilization. In this context, the study of micelle formation in relation with the structural and physico-chemical properties of surfactants is of great interest to better control their use in the different application fields. In this work, we use the MD approach developed by Yoshii et al. and extend it to surfactants with different structures. We aim to systematically investigate different micellar properties as a function of the aggregates size by a molecular dynamics approach, to get an insight into the micellar organization and to collect some relevant descriptors about micelle formation. For this, we perform short MD simulations of preformed micelles of various sizes and analyze three parameters for each micelle size, namely the eccentricity of the micelles, the hydrophobic/hydrophilic surface ratio and the hydrophobic tails hydration. If these parameters are known descriptors of micelles, they were not yet studied in this way by MD. We show that eccentricity, used as “validator” parameter, exhibits minimal values when the aggregate size is close to the experimental aggregation number for surfactants that are known to form spherical micelles. This hence indicates that our methodology gives consistent results. The evolution of the two descriptors follows another scheme, with a sharp increase and decrease, respectively, followed by a leveling-off. The aggregate sizes at which this stabilization starts to occur are close to the respective aggregation number of each surfactant. In our approach, we validate the use of these descriptors to follow micelle formation by MD, from “simple” surfactants to more complex structures, like lipopeptides. Our calculations also suggest that some peculiar behavior, like that of TPC, can be highlighted by our approach. In the context of peptidic surfactants, our methodology could further help to improve computer simulations combined to molecular thermodynamic models to predict micellar properties of those more complex amphiphilic molecules. [less ▲]

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See detailMembrane Interactions of Natural Cyclic Lipodepsipeptides of the Viscosin Group
Geudens, Niels; Nasir, Mehmet Nail ULg; Crowet, Jean-Marc ULg et al

in Biochimica et Biophysica Acta - Biomembranes (2017), 1859(3), 331-339

Many Pseudomonas spp. produce cyclic lipodepsipeptides (CLPs), which, besides their role in biological functions such as motility, biofilm formation and interspecies interactions, are antimicrobial. It ... [more ▼]

Many Pseudomonas spp. produce cyclic lipodepsipeptides (CLPs), which, besides their role in biological functions such as motility, biofilm formation and interspecies interactions, are antimicrobial. It has been established that interaction with the cellular membrane is central to the mode of action of CLPs. In this work, we focus on the CLPs of the so-called viscosin group, aiming to assess the impact of the main structural variations observed within this group on both the antimicrobial activity and the interaction with model membranes. The antimicrobial activity of viscosin, viscosinamide A, WLIP and pseudodesmin A were all tested on a broad panel of mainly Gram-positive bacteria. Their capacity to permeabilize or fuse PG/PE/cardiolipin model membrane vesicles is assessed using fluorescent probes. We find that the Glu2/Gln2 structural variation within the viscosin group is the main factor that influences both the membrane permeabilization properties and the minimum inhibitory concentration of bacterial growth, while the configuration of the Leu5 residue has no apparent effect. The CLPmembrane interactions were further evaluated using CD and FT-IR spectroscopy on model membranes consisting of PG/PE/cardiolipin or POPC with or without cholesterol. In contrast to previous studies, we observe no conformational change upon membrane insertion. The CLPs interact both with the polar heads and aliphatic tails of model membrane systems, altering bilayer fluidity, while cholesterol reduces CLP insertion depth [less ▲]

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See detailGROMPALA: a membrane-implicit modelling method to screen lipid-interacting molecules
Steinhauer, Sven; Crowet, Jean-Marc ULg; Brasseur, Robert ULg et al

in Software and techniques for Bio-molecular modeling (2016)

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See detailModeling of the cyclic lipodepsipeptide Pseudodesmin A self-assembly through molecular dynamic simulations
Crowet, Jean-Marc ULg; Sinnaeve, Davy; Fehér, Kristina et al

Poster (2016, April)

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See detailInteractions of sugar-based bolaamphiphiles with biomimetic systems of plasma membranes
Nasir, Mehmet Nail ULg; Crowet, Jean-Marc ULg; Lins, Laurence ULg et al

in Biochimie (2016), 130

Glycolipids constitute a class of molecules with various biological activities. Among them, sugar-based bolaamphiphiles characterized by their biocompatibility, biodegradability and lower toxicity, became ... [more ▼]

Glycolipids constitute a class of molecules with various biological activities. Among them, sugar-based bolaamphiphiles characterized by their biocompatibility, biodegradability and lower toxicity, became interesting for the development of efficient and low cost lipid-based drug delivery systems. Their activity seems to be closely related to their interactions with the lipid components of the plasma membrane of target cells. Despite many works devoted to the chemical synthesis and characterization of sugar-based bolaamphiphiles, their interactions with plasma membrane have not been completely elucidated. In this work, two sugar-based bolaamphiphiles differing only at the level of their sugar residues were chemically synthetized. Their interactions with membranes have been investigated using model membranes containing or not sterol and with in silico approaches. Our findings indicate that the nature of sugar residues has no significant influence for their membrane interacting properties, while the presence of sterol attenuates the interactions of both bolaamphiphiles with the membrane systems. The understanding of this distinct behavior of bolaamphiphiles towards sterol-containing membrane systems could be useful for their applications as drug delivery systems. [less ▲]

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See detailSimulation par dynamique moléculaire de membranes lipidiques complexes
Crowet, Jean-Marc ULg; Dauchez, Manuel

Scientific conference (2015, November 25)

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See detailModeling of the cyclic lipodepsipeptide Pseudodesmin A self- assembly through molecular dynamic simulations
Crowet, Jean-Marc ULg; Sinnaeve, Davy; Fehér, Kristina et al

Poster (2015, October)

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See detailExperimental and in silico approaches to study the interaction of Remorin with plant plasma membrane : specific interaction of the C-term domain with lipids
Deleu, Magali ULg; Nasir, Mehmet Nail ULg; Gronnier, Julien et al

Conference (2015, September 29)

The function of Remorins, a diverse family of plant-specific proteins (1) is far to be fully elucidated. One of them, StREM1.3 (for Solanum tuberosum Remorin from group 1, homolog 3) has been reported to ... [more ▼]

The function of Remorins, a diverse family of plant-specific proteins (1) is far to be fully elucidated. One of them, StREM1.3 (for Solanum tuberosum Remorin from group 1, homolog 3) has been reported to regulate cell-to-cell propagation of the potato virus X (2). It was also shown to be localized to the inner leaflet of plasma membranes (PMs) and along plasmodesmata, bridges connecting neighbor cells essential for cell-to-cell communication in plants (3). The mechanisms driving StREM1.3 association with PM is still an open question. It was shown recently that a domain of 28 residues at the C-terminus of the potato (RemCA) is required and sufficient for anchoring to the PM (4). Here we combined experimental and in silico biophysics to unravel the molecular bases of RemCA membrane binding. Biomimetic membrane models of plant PM such as monolayers and liposomes were used with various biophysical techniques (Langmuir monolayer technique, Fourier-transformed infrared spectroscopy, circular dichroïsm) and modeling tools (home-made methods and molecular dynamics) (5) to answer to three questions: (i) What is the conformation adopted by RemCA within a membrane?, (ii) Is there any membrane lipid specificity in the RemCA-membrane binding? (iii) What is the role of the two different RemCA domains in the interaction? Results show that RemCA displays a preference for plant phosphoinositide and sitosterol-enriched inner leaflet plasma membrane rafts. Within the membrane, the C-terminal and the N-terminal domains adopt a random coil and a -helical conformation respectively. The C-terminal domain acts as a driver to bind RemCA to the membrane while the N-terminal domain stabilizes the peptide at the membrane. Lysine residues have a crucial importance in this interaction. References (1) Raffaele et al., Plant Physiol., 2007, 145: 593–600 (2) Raffaela et al., Plant Cell, 2009, 21: 1541–1555. (3) Maule, Curr. Opin. Plant Biol., 2008, 11: 680–686. (4) Perraki et al., Plant Physiology, 2012, 160 : 624-637. (5) Deleu et al., Biochim. Biophys. Acta – Biomembranes, 2014, 1838 : 3171-3190. [less ▲]

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