TY - JOUR
T1 - Biomimetic asymmetric bacterial membranes incorporating lipopolysaccharides
AU - Stephan, Mareike S.
AU - Dunsing, Valentin
AU - Pramanik, Shreya
AU - Chiantia, Salvatore
AU - Barbirz, Stefanie
AU - Robinson, Tom
AU - Dimova, Rumiana
PY - 2023/6/6
Y1 - 2023/6/6
N2 - Gram-negative bacteria are equipped with a cell wall that contains a complex matrix of lipids, proteins, and glycans, which form a rigid layer protecting bacteria from the environment. Major components of this outer membrane are the high-molecular weight and amphiphilic lipopolysaccharides (LPSs). They form the extracellular part of a heterobilayer with phospholipids. Understanding LPS properties within the outer membrane is therefore important to develop new antimicrobial strategies. Model systems, such as giant unilamellar vesicles (GUVs), provide a suitable platform for exploring membrane properties and interactions. However, LPS molecules contain large polysaccharide parts that confer high water solubility, which makes LPS incorporation in artificial membranes difficult; this hindrance is exacerbated for LPS with long polysaccharide chains, i.e., the smooth LPS. Here, a novel emulsification step of the inverted emulsion method is introduced to incorporate LPS in the outer or the inner leaflet of GUVs, exclusively. We developed an approach to determine the LPS content on individual GUVs and quantify membrane asymmetry. The asymmetric membranes with outer leaflet LPS show incorporations of 1–16 mol % smooth LPS (corresponding to 16–79 wt %), while vesicles with inner leaflet LPS reach coverages of 2–7 mol % smooth LPS (28–60 wt %). Diffusion coefficient measurements in the obtained GUVs showed that increasing LPS concentrations in the membranes resulted in decreased diffusivity.
AB - Gram-negative bacteria are equipped with a cell wall that contains a complex matrix of lipids, proteins, and glycans, which form a rigid layer protecting bacteria from the environment. Major components of this outer membrane are the high-molecular weight and amphiphilic lipopolysaccharides (LPSs). They form the extracellular part of a heterobilayer with phospholipids. Understanding LPS properties within the outer membrane is therefore important to develop new antimicrobial strategies. Model systems, such as giant unilamellar vesicles (GUVs), provide a suitable platform for exploring membrane properties and interactions. However, LPS molecules contain large polysaccharide parts that confer high water solubility, which makes LPS incorporation in artificial membranes difficult; this hindrance is exacerbated for LPS with long polysaccharide chains, i.e., the smooth LPS. Here, a novel emulsification step of the inverted emulsion method is introduced to incorporate LPS in the outer or the inner leaflet of GUVs, exclusively. We developed an approach to determine the LPS content on individual GUVs and quantify membrane asymmetry. The asymmetric membranes with outer leaflet LPS show incorporations of 1–16 mol % smooth LPS (corresponding to 16–79 wt %), while vesicles with inner leaflet LPS reach coverages of 2–7 mol % smooth LPS (28–60 wt %). Diffusion coefficient measurements in the obtained GUVs showed that increasing LPS concentrations in the membranes resulted in decreased diffusivity.
UR - http://www.scopus.com/inward/record.url?scp=85145615210&partnerID=8YFLogxK
U2 - 10.1016/j.bpj.2022.12.017
DO - 10.1016/j.bpj.2022.12.017
M3 - Article
C2 - 36523159
AN - SCOPUS:85145615210
SN - 0006-3495
VL - 122
SP - 2147
EP - 2161
JO - Biophysical Journal
JF - Biophysical Journal
IS - 11
ER -