Hopanoids like sterols form compact but fluid films

MANGIAROTTI, AGUSTÍN; GALASSI, VANESA V.; PUENTES, ELIDA; OLIVEIRA, RAFAEL; DEL PÓPOLO, MARIO; WILKE, NATALIA

LANGMUIR

AMER CHEMICAL SOC

Lugar: Washington; Año: 2019

0743-7463

p { margin-bottom: 0.14in; direction: ltr; line-height: 120%; text-align: center; }p.western { font-family: "Times",serif; font-size: 20pt; font-weight: bold; }p.cjk { font-family: "Times"; font-size: 20pt; font-weight: bold; }p.ctl { font-family: "Times"; }a:link { color: rgb(0, 0, 255); }Hopanoids are pentacyclic molecules present in membranes from some bacteria,which are proposed as sterol-surrogates in sterol-lacking bacteria. Diplopterol is an abundant hopanoid that, similar to sterols, do notself-aggregate in lamellar struc-tures when pure, but formsmonolayers at the air-water interface. Here we compare the surfacebehavior of pure diploperol with sterols from different organisms,cholesterol from mammals, ergosterol from fungi and stigmasterol fromplants. For this, we prepared Langmuir monolayers of the compoundsand studied their surface properties using different experimentalapproaches, and molecular dynamics simulations. Our results indicatethat diplopterol forms compact films with low mean molecular areas,high surface potentials and high refractive index, all propertiesshared with with solid-like films. The shear viscosity, however, istypical for fluid films. These properties are shared with the studiedsterols, suggesting that the hopanoid is able to induceliquid-ordered phase state such as the sterols do.p { margin-bottom: 0.14in; direction: ltr; line-height: 120%; text-align: center; }p.western { font-family: "Times",serif; font-size: 20pt; font-weight: bold; }p.cjk { font-family: "Times"; font-size: 20pt; font-weight: bold; }p.ctl { font-family: "Times"; }a:link { color: rgb(0, 0, 255); }