AFM characterization of gramicidin-A in tethered lipid membrane on silicon surface

Tethered lipid bilayers were formed on oxidized Si surfaces using the avidin-biotin interaction to investigate the lipid-membrane protein interactions by using gramicidin-A (g-A) as a model membrane protein. The morphology of the tethered lipid bilayer, observed by in situ atomic force microscopy (AFM), changed drastically by the reconstruction of g-A. The aggregation behavior of g-A was clearly different in the tethered membrane from those in simple supported membranes on mica and SiO2 surfaces.

Formation of a gramicidin-A (g-A)-incorporated tethered lipid bilayer on avidin-modified SiO2/Si(1 0 0) surface by the vesicle fusion method. Linear agglomerates of head-to-head single-stranded helices (HHSH) g-A hexamers unique to the tethered bilayer were observed by atomic force microscopy.