Laboratoire

23 juil
23/juil/2020

Laboratoire

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Trois papiers quasi-consécutifs en Juin:

1.    C. Rispe et al.,

Abstract to come

2.    N. Hugouvieux-Cotte-Pattat, C. Brochier-Armanet, J. P. Flandrois, S. Reverchon, Dickeya poaceiphila sp. nov., a plant-pathogenic bacterium isolated from sugar cane (Saccharum officinarum). Int J Syst Evol Microbiol. In press (2020).

Abstract to come

3.    M. Salvador-Castell, B. Deme, P. Oger, J. Peters, Lipid Phase Separation Induced by the Apolar Polyisoprenoid Squalane Demonstrates Its Role in Membrane Domain Formation in Archaeal Membranes. Langmuir 10.1021/acs.langmuir.0c00901 (2020).

Archaea synthesize methyl-branched, ether phospholipids, which confer the archaeal membrane exceptional physicochemical properties. A novel membrane organization was proposed recently to explain the thermal and high pressure tolerance of the polyextremophilic archaeon Thermococcus barophilus. According to this theoretical model, apolar molecules could populate the midplane of the bilayer and could alter the physicochemical properties of the membrane, among which is the possibility to form membrane domains. We tested this hypothesis using neutron diffraction on a model archaeal membrane composed of two archaeal diether lipids with phosphocholine and phosphoethanolamine headgroups in the presence of the apolar polyisoprenoid squalane. We show that squalane is inserted in the midplane at a maximal concentration between 5 and 10 mol % and that squalane can modify the lateral organization of the membrane and induces the coexistence of separate phases. The lateral reorganization is temperature- and squalane concentration-dependent and could be due to the release of lipid chain frustration and the induction of a negative curvature in the lipids.