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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.)

On the temperature stability of extracellular hemoglobin of Glossoscolex paulistus, at different oxidation states: SAXS and DLS studies

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Author(s):
Carvalho, Jose Wilson P. [1] ; Santiago, Patricia S. [1, 2] ; Batista, Tatiana [1] ; Garrido Salmon, Carlos Ernesto [3] ; Barbosa, Leandro R. S. [4] ; Itri, Rosangela [4] ; Tabak, Marcel [1]
Total Authors: 7
Affiliation:
[1] Univ Sao Paulo, Inst Quim Sao Carlos, Sao Carlos, SP - Brazil
[2] Univ Estadual Paulista, Registro, SP - Brazil
[3] Univ Sao Paulo, Fac Filosofia Ciencias & Letras Ribeirao Preto, Dept Fis, Ribeirao Preto, SP - Brazil
[4] Univ Sao Paulo, Inst Fis, BR-01498 Sao Paulo - Brazil
Total Affiliations: 4
Document type: Journal article
Source: Biophysical Chemistry; v. 163, p. 44-55, APR 2012.
Web of Science Citations: 11
Abstract

Glossoscolex paulistus hemoglobin (HbGp) was studied by dynamic light scattering (DLS) and small angle X-ray scattering (SAXS). DLS melting curves were measured for met-HbGp at different concentrations. SAXS temperature studies were performed for oxy-, cyanomet- and met-HbGp forms, at several pH values. At pH 5.0 and 6.0, the scattering curves are identical from 20 to 60 degrees C, and R-g is 108 angstrom, independent of the oxidation form. At pH 7.0, protein denaturation and aggregation occurs above 55 degrees C and 60 degrees C, for oxy and met-HbGp, respectively. Cyanomet-HbGp, at pH 7.0, is stable up to 60 degrees C. At alkaline pH (8.0-9.0) and higher temperature, an irreversible dissociation process is observed, with a decrease of R-g, D-max and I(0). Analysis by p(r), obtained from GNOM, and OLIGOMER, was used to fit the SAXS experimental scattering curves by a combination of theoretical curves obtained for HbLt fragments from the crystal structure. Our results show clearly the increasing contribution of smaller molecular weight fragments, as a function of increasing pH and temperature, as well as, the order of thermal stabilities: cyanomet-> oxy- > met-HbGp. (C) 2012 Elsevier B.V. All rights reserved. (AU)

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