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Visualizing filamentous actin on lipid bilayers by atomic force microscopy in solution
Author(s) -
Shi D.,
Somlyo A. V.,
Somlyo A. P.,
Shao Z.
Publication year - 2001
Publication title -
journal of microscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.569
H-Index - 111
eISSN - 1365-2818
pISSN - 0022-2720
DOI - 10.1046/j.1365-2818.2001.00844.x
Subject(s) - protein filament , actin , electron microscope , monolayer , microscopy , atomic force microscopy , resolution (logic) , lipid bilayer , materials science , crystallography , cryo electron microscopy , lipid raft , biophysics , chemistry , nanotechnology , membrane , optics , physics , biology , composite material , biochemistry , artificial intelligence , computer science
The surface structure of actin filaments (F‐actin) was visualized at high resolution, by atomic force microscopy (AFM) in aqueous solution, in large paracrystals prepared on positively charged lipid monolayers. The increased stability of these closely packed specimens allowed us to show that both the long pitch (38 nm) and the monomer (5.8 nm) can be directly resolved by AFM in the contact mode. The right‐handed helical surface, distinguishable in high resolution images, was compared with reconstructed models based on electron microscopy. The height of the rafts, a measure of the actin filament diameter, was 10 ± 1 nm, whereas the smaller inter‐filament distance, 8 ± 1 nm, was consistent with interdigitation of the filaments. The 10 ± 1 nm F‐actin diameter is in good agreement with the results of fibre X‐ray diffraction. As such specimens are relatively easy to prepare without specialized equipment, this method may allow the study of the thin filaments in which F‐actin‐associated proteins are also present.