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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.)

Denaturant effects on HbGp hemoglobin as monitored by 8-anilino-1-naphtalene-sulfonic acid (ANS) probe

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Barros, Ana E. B. [1] ; Carvalho, Francisco A. O. [1] ; Alves, Fernanda R. [1] ; Carvalho, Jose W. P. [1, 2] ; Tabak, Marcel [1]
Total Authors: 5
[1] Univ Sao Paulo, Inst Quim Sao Carlos, BR-05508 Sao Paulo, SP - Brazil
[2] Univ Estado Mato Grosso, Cuiaba, MT - Brazil
Total Affiliations: 2
Document type: Journal article
Source: International Journal of Biological Macromolecules; v. 74, p. 327-336, MAR 2015.
Web of Science Citations: 6

Glossoscolex paulistus extracellular hemoglobin (HbGp) stability has been monitored in the presence of denaturant agents. 8-Anilino-1-naphtalene-sulfonic acid (ANS) was used, and spectroscopic and hydrodynamic studies were developed. Dodecyltrimethylammonium bromide (DTAB) induces an increase in ANS fluorescence emission intensity, with maximum emission wavelength blue-shifted from 517 to 493 nm. Two transitions are noticed, at 2.50 and 9.50 mmol/L of DTAB, assigned to ANS interaction with pre-micellar aggregates and micelles, respectively. In oxy-HbGp, ANS binds to protein sites less exposed to solvent, as compared to DTAB micelles. In DTAB HbGp ANS ternary system, at pH 7.0, protein aggregation, oligomeric dissociation and unfolding were observed, while, at pH 5.0, aggregation is absent. DTAB induced unfolding process displays two transitions, one due to oligomeric dissociation and the second one, probably, to the denaturation of dissociated subunits. Moreover, guanidine hydrochloride and urea concentrations above 1.5 and 4.0 mol/L, respectively, induce the full HbGp denaturation, with reduction of ANS-bound oxy-HbGp hydrophobic patches, as noticed by fluorescence quenching up to 1.0 and 5.0 mol/L of denaturants. Our results show clearly the differences in probe sensitivity to the surfactant, in the presence and absence of protein, and new insights into the denaturant effects on HbGp unfolding. (C) 2014 Elsevier B.V. All rights reserved. (AU)

FAPESP's process: 13/09829-8 - Biophysical and structural studies of extracellular hemoglobin of Glossoscolex paulistus, and its monomer d and dodecamer (abcd)3 subunits.
Grantee:Francisco Adriano de Oliveira Carvalho
Support type: Scholarships in Brazil - Post-Doctorate
FAPESP's process: 11/09863-6 - Analysis of giant extracellular hemoglobin from Glossoscolex paulistus (HbGp) and ionic surfactants interaction by isothermal titration calorimetry
Grantee:Fernanda Rosa Alves
Support type: Scholarships in Brazil - Post-Doctorate