Hopanoids like sterols form compact but fluid films

AGUSTIN MANGIAROTTI; VANESA GALASSI; ELIDA N. PUENTES; RAFAEL GUSTAVO OLIVEIRA; MARIO G. DEL POPOLO; WILKE, N.

LANGMUIR

AMER CHEMICAL SOC

Lugar: Washington; Año: 2019 vol. 35 p. 9848 - 9848

0743-7463

opanoids are pentacyclic molecules present in membranes from some bacteria, recently proposed as sterol-surrogates in these organisms. Diplopterol is an abundant hopanoid that, similar to sterols, do not self-aggregate in lamellar structures when pure, but forms monolayers at the air-water interface. Here we analyze the interfacial behavior of pure diplopterol and compare it with sterols from different organisms: cholesterol from mammals, ergosterol from fungi and stigmasterol from plants. We prepared Langmuir monolayers of the compounds and studied their surface properties using different experimental approaches, and molecular dynamics simulations. Our results indicate that the films formed by diplopterol, despite being compact, with low mean molecular areas, high surface potentials and high refractive index, depict shear viscosity values similar to that for fluid films. Altogether our results reveal that hopanoids have similar interfacial behavior than that of sterols, and thus they