Tryptophan-induced nanometrization and hydrophobization of Fe 2+ /Fe 3+ oxyhydroxide green rust crystals enable their insertion into lipid particles
Year: 2026
Type: preprint
Abstract: Compartmentalization and metabolic activity are recognized as intrinsic and essential to both extant life and the first protocells. Minerals found in early-Earth hydrothermal settings, such as the Fe 2+/3+ oxyhydroxide green rust (GR), are not only expected to have promoted the formation and assembly of amphiphiles into vesicles, but also to have acted as precursors of current membrane-embedded bioenergetic enzymes. In a previous paper, we identified nanometric size and surface hydrophobicity as two crucial properties for the embedment of GRCO 3 crystals in amphiphile-based vesicles, and demonstrated their acquisition upon exposure to two components of early hydrothermal settings: nickel and tryptophan. Here, we used lipids as model amphiphiles to systematically investigate how the evolution of size and hydrophobicity parameters in GRCO 3 crystals affects their interaction with free lipids and lipid-based particles, and identify the nature of the resulting GRCO 3 -lipid hybrid systems. By leveraging cryo-electron microscopy as well as zeta potential and Laurdan generalized polarization measurements, we demonstrate that modulations of two parameters are sufficient to drastically modify the fate of GRCO 3 -lipid hybrid systems. Size alone defines the directionality of adsorption processes between electrostatically-compatible GRCO 3 crystals and liposomes, yielding intricate mineral-organic interfaces. Subsequent variations in the surface hydrophobicity of the crystals not only orient the assembly of interacting lipids towards either liposomes or lipid nanoparticles (LNPs), but also enable their embedding within the hydrophobic core of both these lipid-based particles. These results suggest that GRCO 3 would have played numerous roles in the emergence of the first energized protocells, from promoting the synthesis of amphiphiles and their assembly into vesicles to embedding within the latter, thus enhancing them with redox and proto-metabolic properties. These new hybrid systems constitute both ideal tools to experimentally assess the proton-coupled electron transfers that were theorized to happen in the interlayers of GR, and promising platforms for therapeutical or depollution applications.
Source: ChemRxiv
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Funder: Agence Nationale de la Recherche
OpenAlex ID: W7220954046