System setup. All vesicles were obtained by spontaneous aggregation of randomly placed lipids. This method is described in detail elsewhere [1]. An additional long equilibration run of 20 μs was performed for the mixed lipid systems (two artificial pores were present) [2]. In all cases, equilibrium of the vesicle was defined by the flux convergence of the lipid components. The pure POPC vesicle...

In a significant step towards the construction of the semi-synthetic minimal cell, a protein expression system with a minimal set of pure and specific enzymes is required. A novel cell-free transcription and translation system named PURESYSTEM (PS), consisting of a specified set of 36 enzymes and ribosomes, has been entrapped in POPC liposomes for protein synthesis. The PS has been used to tran...

The effects of hydrophobic thickness and the molar phosphatidylglycerol (PG) content of lipid bilayers on the structure and membrane interaction of three cationic antimicrobial peptides were examined: aurein 2.2, aurein 2.3 (almost identical to aurein 2.2, except for a point mutation at residue 13), and a carboxy C-terminal analog of aurein 2.3. Circular dichroism results indicated that all thr...

Val156 of apolipoprotein A-I (apoA-I) was found to be a key amino acid in the structure and function of high density lipoprotein (HDL) (J. Biol. Chem., 275: 26821-26827, 2000). To determine more precisely the functions of the individual amino acids proximal to Val156, serial point mutants of proapoA-I, including V156K, D157K, and A158E, were overexpressed and purified to at least 95% purity. In...

Antimicrobial peptides interact specifically with the membrane of a pathogen and kill the pathogen by releasing its cellular contents. Protegrin-1 (PG-1), a beta-hairpin antimicrobial peptide, is known to exist as a transmembrane monomer in a 1,2-dilauroylphosphatidylcholine (DLPC) bilayer and shows concentration-dependent oligomerization in a 1-palmitoyl-2-oleoylphosphatidylcholine (POPC) bila...

The liquid-liquid (Ld + Lo) coexistence region within a distearoyl-phosphatidylcholine/dioleoyl-phosphatidylcholine/palmitoyl-oleoyl-phosphatidylcholine/cholesterol (DSPC/DOPC/POPC/CHOL) mixture displays a nanoscopic-to-macroscopic transition of phase domains as POPC is replaced by DOPC. Previously, we showed that the transition goes through a modulated phase regime during this replacement, in ...

We study the interaction of alkali metal chlorides with lipid vesicles made of palmitoyloleoylphosphatidylcholine (POPC). An elaborate set of techniques is used to investigate the binding process at physiological conditions. The alkali cation binding to POPC is characterized thermodynamically using isothermal titration calorimetry. The isotherms show that for all ions in the alkali group the bi...

Cholesterol plays a crucial role in modulating the physicochemical properties of membranes, thus influencing membrane transport drugs. In this paper, effects caused by cholesterol on chlorzoxazone (CZX), centrally acting muscle relaxant drug, were probed through molecular dynamics simulations. POPC was selected as model lipid, and three different concentrations (0%, 20%, 50% CHOL) considered. T...