Peptide interactions with phospholipid membranes and surfaces

3 Peptide interactions with phospholipid membranes and surfaces 

It is important to the performance of AMPs that they be efficient in killing bacteria and other pathogens but leave human cells unaffected. The basis for such selectivity is that membranes of bacteria and human cells have different compositions. For example, cholesterol is rich (up to about 45%) in human cell membranes, while it is replaced by ergosterol in fungi and absent in bacteria. There are also differences in phospholipid composition. For example, PC and SM are abundant in the outer layer of erythrocytes, which renders these essentially uncharged. In contrast, the outer membrane of bacteria is rich in anionic lipids, such as phosphatidylglycerol (PG), cardiolipin, 

Adapted from Stromstedt A, Ringstad L, Schmidtchen A, Malmsten M. Interaction between amphiphilic peptides and phospholipid membranes. Curr Opin Colloid Interface Sci 2010 15 467-478. 

Thin Film Coatings for Biomaterials and Biomedical Applications 

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Interest in protein and peptide interactions with phospholipid membranes and surfaces originates from its importance for both key biophysical processes (eg, atherosclerosis, Alzheimer s, and other plaque-related diseases) and a wide range of biomedical applications. For example, control of protein/peptide adsorption allows reduction of inflammation and other unwanted biopharmaceutical effects in phospholipid-based biomaterials and dmg delivery but also improved signal-to-noise in biosensors and... 

Although issues thus remain with simpler aspects of protein/peptide interactions with phospholipid membranes, there has been a clear shift in the past few years to more complex membranes, notably those containing key nonlipid membrane components such as LPS, Upoteichoic acid, and proteoglycans. Protein/peptide interactions with such LPSs are important in various biological contexts, including Upoprotein deposition at proteoglycan-covered endothelial surfaces in atherosclerosis, lectin... 

In the previous section, we showed that, because of their large surface areas, facial amphiphiles are active at hydrophobic/hydrophilic interfaces. This is not only the case for oil/water interfaces but also for the hydrophobic/hydrophilic interface of phospholipid bilayers. Because of this property, facial amphiphilic molecules have been found to carry out a variety of biological functions related to their interaction with cell membranes. One of the most prominent functions of facial amphiphiles is the formation of pores in bilayer membranes. In the case of peptide antibiotics and toxins, depending if the peptide is specific for bacterial or mammalian cells, respectively, the formation of pores leads to lysis of the cells and ultimately cell death. Many other facial amphiphiles form pores to regulate trans-membrane transport, such as the ion channels for selectively transport ions, or release osmotic pressure. 

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