Urea-induced unfolding of Glossoscolex paulistus h... - BV FAPESP
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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Urea-induced unfolding of Glossoscolex paulistus hemoglobin, in oxy- and cyanomet-forms: A dissociation model

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Author(s):
Carvalho, Francisco A. O. [1] ; Carvalho, Jose Wilson P. [1] ; Santiago, Patricia S. [1, 2] ; Tabak, Marcel [1]
Total Authors: 4
Affiliation:
[1] Univ Sao Paulo, Inst Quim Sao Carlos, Sao Paulo, SP - Brazil
[2] Univ Estadual Paulista Julio de Mesquite Filho, Sao Paulo - Brazil
Total Affiliations: 2
Document type: Journal article
Source: International Journal of Biological Macromolecules; v. 52, p. 340-348, JAN 2013.
Web of Science Citations: 6
Abstract

The urea effect on the giant extracellular hemoglobin of Glossoscolex paulistus (HbGp) stability was studied by analytical ultracentrifugation (AUC) and small angle X-ray scattering (SAXS). AUC data show that the sedimentation coefficient distributions curves c (S), at 1.0 mol/L of urea, display a single peak at 57 S, associated to the undissociated protein. The increase in urea concentration, up to 4.0 mol/L, induces the appearance of smaller species, due to oligomeric dissociation. The sedimentation coefficients and molecular masses are 9.2 S and 204 kDa for the dodecamer (abcd)(3), 5.5 S and 69 kDa for the tetramer (abcd), 4.1 S and 52 kDa for the trimer (abc) and 2.0 S and 17 kDa for the monomer d, respectively. SAXS data show initially a decrease in the 1(0) values due to the oligomeric dissociation, and then, above 4.0 mol/L of denaturant, for oxy-HbGp, and above 6.0 mol/L for cyanomet-HbGp, an increase in the maximum dimension and gyration radius is observed, due to the unfolding process. According to AUC and SAXS data the HbGp unfolding is described by two phases: the first one, at low urea concentration, below 4.0 mol/L, characterizes the oligomeric dissociation, while the second one, at higher urea concentration, is associated to the unfolding of dissociated species. Our results are complementary to a recent report based on spectroscopic observations. (C) 2012 Elsevier B.V. All rights reserved. (AU)

FAPESP's process: 09/17261-6 - Oligomeric stability studies of giant extracellular hemoglobin of Glossoscolex paulistus (HbGp) in the presence of chaotropic agents, surfactants and characterization of its subunits.
Grantee:Francisco Adriano de Oliveira Carvalho
Support Opportunities: Scholarships in Brazil - Doctorate
FAPESP's process: 10/09719-0 - Effects of surfactants, iron oxidation state and medium pH upon the thermal stability of giant extracellular hemoglobin of Glossoscolex paulistus in its native oligomeric form and for trimeric ABC and monomeric d globin subunits
Grantee:José Wilson Pires Carvalho
Support Opportunities: Scholarships in Brazil - Doctorate