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

Autor(es)

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]

Afiliação do(s) autor(es)

^[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

• Tipo de documento: Artigo Científico
• Fonte: Biophysical Chemistry; v. 163, p. 44-55, APR 2012.
• Citações Web of Science: 11

Resumo

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)

• Processo FAPESP: 10/09719-0 - Estudos dos efeitos de surfactantes, do estado de oxidação do ferro e do pH do meio na estabilidade térmica da hemoglobina extracelular gigante de Glossoscolex paulistus (HbGp) na forma íntegra e de suas subunidades monômero d e trímero ABC
• Beneficiário: José Wilson Pires Carvalho
• Modalidade de apoio: Bolsas no Brasil - Doutorado