Alamethicin and related membrane channel forming polypeptides

摘要: Alamethicin and several related microbial polypeptides, which contain a high proportion of α-aminoisobutyric acid (Aib) residues, possess the ability to modify permeability properties phospholipid bilayer membranes. induces excitability phenomena in model membranes has served as an excellent for study voltage sensitive transmembrane channels. This review summarizes various aspects structural chemistry membrane modifying alamethicin Alb containing peptides. The presence Aib residues these sequences, constrains polypeptides 310 or α-helical conformations. Functional channels are formed by aggregation cylindrical peptide helices, span lipid bilayer, forming scaffolding aqueous column across membrane. After consideration available data on conductance characteristics channels, working, hypothesis channel is outlined. Channel aggregates phase may be stabilized intermolecular hydrogen bonding, involving central glutamine residue also interactions between macro-dipoles proximate helices. Fluctuations different states rationalized transitions hence altered dimensions core changes net dipole moment aggregate. Ion fluxes through affected electric field within core.