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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.)

pH effect upon HbGp oligomeric stability: characterization of the dissociated species by AUC and DLS studies

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Author(s):
Carvalho, Francisco Adriano O. [1] ; Carvalho, Jose Wilson P. [1] ; Alves, Fernanda Rosa [1] ; Tabak, Marcel [1]
Total Authors: 4
Affiliation:
[1] Univ Sao Paulo, Inst Quim Sao Carlos, Sao Carlos, SP - Brazil
Total Affiliations: 1
Document type: Journal article
Source: International Journal of Biological Macromolecules; v. 59, p. 333-341, AUG 2013.
Web of Science Citations: 13
Abstract

Glossoscolex paulistus (HbGp) extracellular hemoglobin is a giant oligomeric protein. It is constituted by 144 heme containing subunits and non-heme structures (linkers), with a total molecular mass of 3.6 MDa. AUC and DLS studies were developed for three HbGp forms, oxy-, met- and cyanomet-, at several pH values, in order to characterize the species in solution upon oligomeric dissociation. Isolated SEC fractions, trimer and dodecamer, are less stable as compared to the whole oxy-HbGp. The monomer d displays a large thermal stability up to 59 degrees C. Hydrodynamic properties of the isolated subunits are very similar to those described for them in the whole protein, in the presence of urea or at pH 10.0. The degree of HbGp oligomeric dissociation, in alkaline pH, depends significantly on the iron oxidation state. Also on the ligand coordinated to the heme iron. Thus, at pH 8.0, the oxy-HbGp is partially dissociated, while the metform is fully dissociated. The cyanomet-HbGp remains undissociated. Our present results show that the effect of pH on the HbGp oligomeric stability is similar to that associated to the urea-induced unfolding. Simultaneous use of AUC and DLS allowed the characterization of the species in the SEC fractions of isolated HbGp subunits. (C) 2013 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: 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 Opportunities: Scholarships in Brazil - Post-Doctoral
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