Lysozyme viscoelastic matrices in tetramethylurea/water media: A small angle X-ray scattering study

Marcelo A. Da Silva, Rosângela Itri, Elizabeth P.G. Arêas

Research output: Contribution to journalArticlepeer-review

15 Citations (SciVal)

Abstract

Semi-solid viscoelastic matrices produced out of lysozyme in organic/aqueous media [tetramethylurea (TMU)/water] were characterized by small angle X-ray scattering (SAXS). The scattering curves were modeled in their form and interference factors. Radii of gyration of scattering particles were found to undergo a dramatic increase from 14 Å in water to approximately 44 Å in the matrices. Average correlation distances d=155 Å were consistently verified for the scattering particles in the matrices, irrespective of solvent composition (in the 0.6≤wTMU≤0.8 range), in contrast to what is observed in water (d=62 Å). At wTMU=0.9, however, a slight increase in Rg (to Rg=49 Å) leads to interdigitation with the apolar prevailing medium of the matrix leading to the loss of the interference effect. Low dimensionality derived from the modeling procedure could be taken to indicate mass fractal character of the unfolded species, although polydispersion of samples could also have some contribution to that result. Despite the very significant shape distortion of the unfolded protein forms in the matrices, they still retain considerable globular character, as indicated by the Kratky plots obtained. The morphological results obtained in this work are compatible with the dynamical behavior displayed by the systems.

Original languageEnglish
Pages (from-to)169-179
Number of pages11
JournalBiophysical Chemistry
Volume99
Issue number2
Early online date5 Oct 2002
DOIs
Publication statusPublished - 16 Oct 2002

Keywords

  • Fractals
  • Lysozyme
  • Protein networks
  • Rheology
  • Small angle X-ray scattering
  • Viscoelasticity

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Organic Chemistry

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