Supramolecular Assembly of Biological Molecules Purified from Bovine Nerve Cells: from Microtubule Bundles and Necklaces to Neurofilament Networks

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Zach Wissner-Gross (March 16, 2009)

Information

Supramolecular assembly of biological molecules purified from bovine nerve cells: from microtubule bundles and necklaces to neurofilament networks

Daniel J. Needleman, Janya B. Jones, Uri Raviv, Miguel A. Ojeda-Lopez, H. P. Miller, Y. Li, L. Wilson, and C. R. Safinya

Journal of Physics: Condensed Matter, 2005, 17, S3225-S3230

Soft matter keywords

Self-assembly, packing structure

Summary

Needleman et al. examine the behavior of neurofilaments (NFs) in vitro in solutions containing different polyelectrolytes (i.e., in different salt solutions). In short, they found that the NFs formed hexagonal bundles in solutions with containing cations with a greater charge and larger size, while the NFs formed what the authors term "living necklace bundles" in solutions containing bivalent cations (Figure 1). The authors go on to quantify this bundling via scattering experiments, although optical and electron micrographs seem to sufficiently reveal the bundling behaviors.

Soft matter discussion

I found it rather remarkable that NFs exhibit such different bundling behaviors in the presence of different cations. In this paper, the authors avoid any substantial discussion of why the cations induce different self-assemblies, but that is primarily because the work presented in this paper was originally published a year earlier in PNAS [1]. In that paper,