Atomic force microscopy imaging of Xenopus laevis oocyte plasma membrane purified by ultracentrifugation.
Atomic force microscopy (AFM) was used to investigate the native plasma membrane of Xenopus laevis (X. laevis) oocyte purified by means of ultracentrifugation on sucrose gradient and subsequently adsorbed on mica leaves through a physisorption process. Reproducible AFM topography images were collected, analyzed, and compared. AFM images showed the presence of large single or double bilayer membrane sheets covered with protein complexes. The lateral dimension and height of protein complexes imaged in air showed a normal distribution centred on 15.4 +/- 0.4 nm (mean +/- SE; n = 59) and 3.9 +/- 0.2 nm (mean +/- SE; n = 57), respectively. A density of about 270 protein complexes per square micron was calculated. Less frequently, ordered nanometer domains with densely packed protein complexes arranged in hexagonal patterns were also visualized in AFM images, confirming previously published data. Their lateral dimension and height showed a normal distribution centred on 23.0 +/- 0.4 nm (mean +/- SE; n = 42) and 1.5 +/- 0.6 nm (mean +/- SE; n = 90), respectively. A density of about 870 protein complexes per square micrometer was calculated. Advantages and drawbacks of this new sample preparation for AFM imaging are discussed.
Santacroce
Massimo
M
Giovanni Esposito Institute of General Physiology and Biological Chemistry, University of Milan, Via Trentacoste 2, Milan, Italy.
Orsini
Francesco
F
Mari
Stefania Anna
SA
Marinone
Massimo
M
Lenardi
Cristina
C
Bettè
Sara
S
Sacchi
Vellea Franca
VF
Poletti
Giulio
G
D000818:Animals; D002462:Cell Membrane / Q000648:ultrastructure*; D002499:Centrifugation, Density Gradient; D005260:Female; D008051:Lipid Bilayers; D046911:Macromolecular Substances; D018625:Microscopy, Atomic Force; D009865:Oocytes / Q000648:ultrastructure*; D014982:Xenopus laevis
D008051:Lipid Bilayers; D046911:Macromolecular Substances