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. 2000 Feb;78(2):950–958. doi: 10.1016/S0006-3495(00)76652-5

Cryoatomic force microscopy of filamentous actin.

Z Shao 1, D Shi 1, A V Somlyo 1
PMCID: PMC1300697  PMID: 10653807

Abstract

Cryoatomic force microscopy (cryo-AFM) was used to image phalloidin-stabilized actin filaments adsorbed to mica. The single filaments are clearly shown to be right-handed helical structures with a periodicity of approximately 38 nm. Even at a moderate concentration ( approximately 10 microg/ml), narrow, branched rafts of actin filaments and larger aggregates have been observed. The resolution achieved is sufficient to resolve actin monomers within the filaments. A closer examination of the images shows that the branched rafts are composed of up to three individual filaments with a highly regular lateral registration with a fixed axial shift of approximately 13 nm. The implications of these higher-order structures are discussed in terms of x-ray fiber diffraction and rheology of actin gels. The cryo-AFM images also indicate that the recently proposed model of left-handed F-actin is likely to be an artifact of preparation and/or low-resolution AFM imaging.

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Selected References

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