Sodium dodecyl sulfate (SDS) effect on the thermal stability of oxy-HbGp: Dynamic light scattering (DLS) and small angle X-ray scattering (SAXS) studies

Autor(es)

Carvalho, Jose Wilson P. ^[1] ; Alves, Fernanda Rosa ^[1] ; Batista, Tatiana ^{[1, 2]} ; Carvalho, Francisco Adriano O. ^[1] ; Santiago, Patricia S. ^{[1, 3]} ; Tabak, Marcel ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Inst Quim Sao Carlos, Sao Carlos, SP - Brazil

^[2] Univ Estadual Maringa, Maringa, Parana - Brazil

^[3] Univ Estadual Paulista, Registro, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: COLLOIDS AND SURFACES B-BIOINTERFACES; v. 111, p. 561-570, NOV 1 2013.
• Citações Web of Science: 7

Resumo

Glossoscolex paulistus (HbGp) hemoglobin is an oligomeric protein, presenting a quaternary structure constituted by 144 globin and 36 non-globin chains (named linkers) with a total molecular mass of 3.6 MDa. SDS effects on the oxy-HbGp thermal stability were studied, by DLS and SAXS, at pH 5.0, 7.0 and 9.0. DLS and SAXS data show that the SDS-oxy-HbGp interactions induce a significant decrease of the protein thermal stability, with the formation of larger aggregates, at pH 5.0. At pH 7.0, oxy-HbGp undergoes complete oligomeric dissociation, with increase of temperature, in the presence of SOS. Besides, oxy-HbGp 3.0 mg/mL, pH 7.0, in the presence of SDS, has the oligomeric dissociation process reduced as compared to 0.5 mg/mL of protein. At pH 9.0, oxy-HbGp starts to dissociate at 20 degrees C, and the protein is totally dissociated at 50 degrees C. The thermal dissociation kinetic data show that oxy-HbGp oligomeric dissociation at pH 7.0, in the presence of SDS, is strongly dependent on the protein concentration. At 0.5 mg/mL of protein, the oligomeric dissociation is complete and fast at 40 and 42 degrees C, with kinetic constants of (2.1 +/- 0.2) x 10(-4) and (5.5 +/- 0.4) x 10(-4)s(-1), respectively, at 0.6 mmol/L SOS. However, at 3.0 mg/mL, the oligomeric dissociation process starts at 46 degrees C, and only partial dissociation, accompanied by aggregates formation is observed. Moreover, our data show, for the first time, that, for 3.0 mg/mL of protein, the oligomeric dissociation, denaturation and aggregation phenomena occur simultaneously, in the presence of SDS. Our present results on the surfactant-HbGp interactions and the protein thermal unfolding process correspond to a step forward in the understanding of SDS effects. (C) 2013 Elsevier B.V. All rights reserved. (AU)

• Processo FAPESP: 09/17261-6 - Estudo da estabilidade oligomérica da hemoglobina extracellular gigante de Glossoscolex paulistus (HbGp) na presença de agentes caotrópicos, surfactantes e caracterização das subunidades.
• Beneficiário: Francisco Adriano de Oliveira Carvalho
• Modalidade de apoio: Bolsas no Brasil - Doutorado
• Processo FAPESP: 11/09863-6 - Análise da interação da hemoglobina extracelular gigante de Glossoscolex paulistus (HbGp) com surfactantes iônicos por calorimetria de titulação isotérmica
• Beneficiário: Fernanda Rosa Alves
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado
• 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