Wide scale range structure in polyelectrolyte-protein dense complexes: where Sans meets freeze-fracture microscopy

J Phys Chem B. 2007 Jul 26;111(29):8540-6. doi: 10.1021/jp068878l. Epub 2007 Jun 8.

Abstract

We show in this paper how the combination of SANS and freeze-fracture electron microscopy (FFEM) is a powerful tool to picture the structure of very turbid sample liquids at spatial scales lying from a few A to several microns. In a given range of chain size and species concentrations, primary complexes in the shape of globules are observed by both techniques. SANS allows a precise quantitation of size, inner structure, and composition of these globules, as well as aggregated structure of the globules at larger scales, which is fractal-like, with a Hausdorff dimension 2.1 characteristic of Reaction Limited Aggregation (RCLA). The existence of aggregates is seen by FFEM, but most of all FFEM shows the lack of any further structure at larger scale, up to the micrometer size.

Publication types

  • Evaluation Study

MeSH terms

  • Animals
  • Electrolytes / chemistry
  • Freeze Fracturing*
  • Humans
  • Microscopy, Electron / methods*
  • Polymers / chemistry
  • Protein Conformation
  • Proteins / chemistry*

Substances

  • Electrolytes
  • Polymers
  • Proteins