| Texto completo | |
| Autor(es): |
Alves, Fernanda Rosa
[1]
;
Carvalho, Francisco Adriano O.
[1]
;
Carvalho, Jose Wilson P.
[2]
;
Tabak, Marcel
[1]
Número total de Autores: 4
|
| Afiliação do(s) autor(es): | [1] Univ Sao Paulo, Inst Quim Sao Carlos, Sao Carlos, SP - Brazil
[2] Univ Estado Mato Grosso, Barra Do Bugres, MT - Brazil
Número total de Afiliações: 2
|
| Tipo de documento: | Artigo Científico |
| Fonte: | Biopolymers; v. 105, n. 4, p. 199-211, APR 2016. |
| Citações Web of Science: | 1 |
| Resumo | |
In this work, isothermal titration and differential scanning calorimetric methods, in combination with pyrene fluorescence emission and dynamic light scattering have been used to investigate the interaction of dodecyltrimethylammonium bromide (DTAB) with the giant extracellular Glossoscolex paulistus hemoglobin (HbGp) in the oxy-form, at pH values around the isoelectric point (pI approximate to 5.5). Our ITC results have shown that the interaction of DTAB with the hemoglobin is more intense at pH 7.0, with a smaller cac (critical aggregation concentration) value. The increase of protein concentration does not influence the cac value of the interaction, at both pH values. Therefore, the beginning of the DTAB-oxy-HbGp premicellar aggregates formation, in the cac region, is not affected by the increase of protein concentration. HSDSC studies show higher T-m values at pH 5.0, in the absence and presence of DTAB, when compared with pH 7.0. Furthermore, at pH 7.0, an aggregation process is observed with DTAB in the range from 0.75 to 1.5 mmol/L, noticed by the exothermic peak, and similar to that observed for pure oxy-HbGp, at pH 5.0, and in the presence of DTAB. DLS melting curves show a decrease on the hemoglobin thermal stability for the oxy-HbGp-DTAB mixtures and formation of larger aggregates, at pH 7.0. Our present data, together with previous results, support the observation that the protein structural changes, at pH 7.0, occur at smaller DTAB concentrations, as compared with pH 5.0, due to the acidic pI of protein that favors the oxy-HbGp-cationic surfactant interaction at neutral pH. (C) 2015 Wiley Periodicals, Inc. (AU) | |
| Processo FAPESP: | 13/09829-8 - Estudos biofísicos e estruturais da hemoglobina extracelular de Glossoscolex paulistus, e das suas subunidades monômero d e dodecâmero (abcd)3. |
| Beneficiário: | Francisco Adriano de Oliveira Carvalho |
| Modalidade de apoio: | Bolsas no Brasil - Pós-Doutorado |