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

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

doi:10.1016/S0301-4622(02)00144-8

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

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

Department of Chemistry

University of São Paulo

Research output: Contribution to journal › Article › peer-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≤w_TMU≤0.8 range), in contrast to what is observed in water (d=62 Å). At w_TMU=0.9, however, a slight increase in R_g (to R_g=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 language	English
Pages (from-to)	169-179
Number of pages	11
Journal	Biophysical Chemistry
Volume	99
Issue number	2
Early online date	5 Oct 2002
DOIs	https://doi.org/10.1016/S0301-4622(02)00144-8
Publication status	Published - 16 Oct 2002

Funding

We thank the National Laboratory of Synchrotron Light (LNLS, Campinas, Brazil (Proc. 644/00)) for the use of their facilities. This work is part of a project by one of the authors (E.P.G. Arêas), supported by FAPESP (Brazil). It contains part of the work developed in the Master's thesis of M.A. da Silva, to whom a CNPq (Brazil) scholarship has been granted. R. Itri and E.P.G. Arêas are grateful to CNPq for the grant of research fellowships. R. Itri also thanks support from FAPESP and CAPES.

Keywords

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

ASJC Scopus subject areas

Biophysics
Biochemistry
Organic Chemistry

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

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 {\AA} in water to approximately 44 {\AA} in the matrices. Average correlation distances d=155 {\AA} 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 {\AA}). At wTMU=0.9, however, a slight increase in Rg (to Rg=49 {\AA}) 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.",

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

Abstract

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Keywords

ASJC Scopus subject areas

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