Phase-transition-induced protein redistribution in lipid bilayers.
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.
Seeger
Heiko M
HM
CNR-INFM-S3 National Center on nanoStructures and bioSystems at Surfaces, Via Campi 213/A, 41125 Modena, Italy.
Bortolotti
Carlo A
CA
Alessandrini
Andrea
A
Facci
Paolo
P
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
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