The Membrane as a Transporter, Ion Channels and Membrane Pumps - Membrane Biophysics, Biological and Medical Physics, Biomedical Engineering - page 66

Fig. 4.11 These model diagrams represent various events that might change the transport
properties of phospholipid membranes through the creation of ion-conducting pores or other
membrane-disrupting events. a Hydrophobic polypeptides form trans-membrane helical bundles.
b The wormhole model. c The carpet model. d The in-plane diffusion model: peptide monomers are
surrounded by areas of bilayer with irregular lipid packing characteristics. These diffuse along the
surface of the bilayer causing transient openings when zones of metastability overlap. Alternatively,
the detergent-like action of amphipathic peptides leads to the formation of peptide-lipid micelles,
bilayer openings, and the transient formation of pores. e The disruption of the lipid bilayer packing
due to in-plane inserted peptides is schematically illustrated for monomers and side-to-side dimers.
In all these schematic diagrams one thing can be found in common, which is the mechanism behind
the creation of these membrane-disrupting events. The possible lipid peptide interactions play an
important role behind the creation of any lipid peptide complexes. For details beyond the description
presented the reader is referred to Chap. 5 . This figure has been adapted from [ 12 , 13 ] with due
permission from the publisher
4.6.2 The Wormhole Model
This is a modified form of a trans-membrane helical bundle model, in which lipids,
together with peptides, are assumed to be lining across the cylindrical pore's surface.