title: Phase-transition-induced protein redistribution in lipid bilayers.
abstract: We report an atomic force microscopy study on the lateral spatial redistribution of an integral membrane protein reconstituted in supported lipid bilayers (SLBs) subjected to a thermally induced phase transition. KcsA proteins were reconstituted in proteoliposomes of POPE/POPG (3:1, mol/mol), and SLBs, including the proteins, were then obtained by the vesicle fusion technique on mica. By decreasing the temperature, the lipid bilayer passed from a liquid disordered (l(d)) phase in which the proteins are homogeneously distributed to a coexistence of solid ordered (s(o)) and l(d) domains with the proteins preferentially distributed in the l(d) domains. The inhomogeneous distribution eventually led to protein clustering. The obtained results are discussed in light of the role that the lipid/protein interaction can have in determining the function of integral membrane proteins.
authors.affiliation: CNR-INFM-S3 National Center on nanoStructures and bioSystems at Surfaces, Via Campi 213/A, 41125 Modena, Italy.
authors.forename: Heiko M
authors.initials: HM
authors.lastname: Seeger
authors.forename: Carlo A
authors.initials: CA
authors.lastname: Bortolotti
authors.forename: Andrea
authors.initials: A
authors.lastname: Alessandrini
authors.forename: Paolo
authors.initials: P
authors.lastname: Facci
mesh_terms: D000538:Aluminum Silicates / Q000737:chemistry; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics; D008051:Lipid Bilayers / Q000737:chemistry*; D018625:Microscopy, Atomic Force; D044367:Phase Transition; D010714:Phosphatidylethanolamines / Q000737:chemistry; D010715:Phosphatidylglycerols / Q000737:chemistry; D015221:Potassium Channels / Q000737:chemistry* / Q000235:genetics; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics; D017550:Spectroscopy, Fourier Transform Infrared; D013696:Temperature
chemical_list: D000538:Aluminum Silicates; D001426:Bacterial Proteins; D008051:Lipid Bilayers; D010714:Phosphatidylethanolamines; D010715:Phosphatidylglycerols; D015221:Potassium Channels; D011994:Recombinant Proteins; C107790:prokaryotic potassium channel; C057561:1-palmitoyl-2-oleoylphosphatidylethanolamine; C060037:1-palmitoyl-2-oleoylglycero-3-phosphoglycerol; C011934:mica