The outer membrane (OM) of gram-negative bacteria consists of a lipid bilayer, which is composed of phospholipids in the periplasmic leaflet and of lipopolysaccharide in the outer leaflet. Integral membrane proteins facilitate transport, for example, of nutrients, across this hydrophobic barrier.After their biosynthesis, outer membrane proteins (OMPs) are targeted to the cytoplasmic membrane in...

Making and holding an artificial lipid bilayer horizontally in an aqueous solution within the microscopic working distance of ~100 μm are essential for simultaneous single molecule imaging and single ion-channel electrical current recording. However, preparation of such a lipid bilayer without a solid support is technically challenging. In a typical supported lipid bilayer, the asymmetric local...

The proton pump transmembrane protein bacteriorhodopsin was successfully incorporated into planar floating lipid bilayers in gel and fluid phases, by applying a detergent-mediated incorporation method. method optimized on single supported using quartz crystal microbalance, atomic force fluorescence microscopy techniques. Neutron X-ray reflectometry were used both with the aim of determining str...

This paper deals with the effect of different size gold nanoparticles on the fluidity of lipid membrane at different regions of the bilayer. To investigate this, we have considered significantly large bilayer leaflets and incorporated only one nanoparticle each time, which was subjected to all atomistic molecular dynamics simulations. We have observed that, lipid molecules located near to the g...

The lipid bilayer vesicle is a model of the cellular membrane. Even in this simple system, however, measuring the thermodynamics of membrane protein association is a challenge. Here we discuss Forster resonance energy transfer (FRET) in liposomes as a method to probe the dimerization of transmembrane helices in a membrane environment. Although the measurements are labor intensive, FRET in lipos...

Fusion between two lipid bilayers is one of the central processes in cell biology, playing a key role in endocytosis, exocytosis, and vesicle transport. We have previously developed a model system that uses the hybridization of complementary DNA strands to model the formation of the SNARE four-helix bundle that mediates synaptic vesicle fusion and used it to study vesicle fusion to a tethered l...

C ompartmentalization is a key principle for the functional organization of living cells (1). Transport across compartmental boundaries and, in particular, across the cell wall is controlled by membrane proteins that act as selective channels and transporters. Puncturing the boundaries leads to pathologies, e.g., in the case of toxins, but is also an opportunity for treatment, e.g., in the case...

We have used pHLIP® [pH (low) insertion peptide] to study the roles of carboxyl groups in transmembrane (TM) peptide insertion. pHLIP binds to the surface of a lipid bilayer as a disordered peptide at neutral pH; when the pH is lowered, it inserts across the membrane to form a TM helix. Peptide insertion is reversed when the pH is raised above the characteristic pK(a) (6.0). A key event that fa...

We explore the effects of the peripheral and transmembrane antimicrobial peptides on the lipid bilayer membrane by using the coarse grained Dissipative Particle Dynamics simulations. We study peptide/lipid membrane complexes by considering peptides with various structure, hydrophobicity and peptide/lipid interaction strength. The role of lipid/water interaction is also discussed. We discuss a r...