1. Characterisation of a synthetic Archeal membrane reveals a possible new adaptation route to extreme conditions.
- Author
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Salvador-Castell, Marta, Golub, Maksym, Erwin, Nelli, Demé, Bruno, Brooks, Nicholas J., Winter, Roland, Peters, Judith, and Oger, Philippe M.
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PHOSPHOLIPIDS , *MONOMOLECULAR films , *POLYISOPRENOID compounds , *NEUTRON diffraction , *FLUORESCENCE spectroscopy - Abstract
It has been proposed that adaptation to high temperature involved the synthesis of monolayer-forming ether phospholipids. Recently, a novel membrane architecture was proposed to explain the membrane stability in polyextremophiles unable to synthesize such lipids, in which apolar polyisoprenoids populate the bilayer midplane and modify its physico-chemistry, extending its stability domain. Here, we have studied the effect of the apolar polyisoprenoid squalane on a model membrane analogue using neutron diffraction, SAXS and fluorescence spectroscopy. We show that squalane resides inside the bilayer midplane, extends its stability domain, reduces its permeability to protons but increases that of water, and induces a negative curvature in the membrane, allowing the transition to novel non-lamellar phases. This membrane architecture can be transposed to early membranes and could help explain their emergence and temperature tolerance if life originated near hydrothermal vents. Transposed to the archaeal bilayer, this membrane architecture could explain the tolerance to high temperature in hyperthermophiles which grow at temperatures over 100 °C while having a membrane bilayer. The induction of a negative curvature to the membrane could also facilitate crucial cell functions that require high bending membranes. By studying the properties of a synthetic membrane mimicking an archaeal membrane and containing the apolar polyisoprenoid squalane, Salvador-Castell et al. show that lipid bilayer stability and functionality are shifted to higher temperatures under high pressure. These findings support the view that apolar lipids may constitute an adaptative route to high-temperature tolerance in archaeal hyperthermophiles. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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