Carvalho, José Wilson P.Alves, Fernanda RosaBatista, TatianaCarvalho, Francisco Adriano O.Santiago, Patrícia S. [UNESP]Tabak, Marcel2014-05-272014-05-272013-11-01Colloids and Surfaces B: Biointerfaces, v. 111, p. 561-570.0927-77651873-4367http://hdl.handle.net/11449/76888Glossoscolex 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 3.6MDa. 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 SDS. Besides, oxy-HbGp 3.0mg/mL, pH 7.0, in the presence of SDS, has the oligomeric dissociation process reduced as compared to 0.5mg/mL of protein. At pH 9.0, oxy-HbGp starts to dissociate at 20°C, and the protein is totally dissociated at 50°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 0.5mg/mL of protein, the oligomeric dissociation is complete and fast at 40 and 42°C, with kinetic constants of (2.1±0.2)×10-4 and (5.5±0.4)×10-4s-1, respectively, at 0.6mmol/L SDS. However, at 3.0mg/mL, the oligomeric dissociation process starts at 46°C, and only partial dissociation, accompanied by aggregates formation is observed. Moreover, our data show, for the first time, that, for 3.0mg/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. © 2013 Elsevier B.V.561-570engDLSGlossoscolex paulistusOligomeric dissociationSAXSSDSThermal stabilityAggregation phenomenaProtein concentrationsProtein thermal stabilitySmall angle X-ray scatteringAggregatesDissociationDynamic light scatteringHemoglobinOligomersProteinsThermodynamic stabilitySodium dodecyl sulfatedodecyl sulfate sodiumGlossoscolex paulistus hemoglobinhemoglobinoligomerunclassified drugconcentration (parameters)controlled studydissociationdynamic light scatteringhigh temperature procedureskineticslight scatteringmolecular weightpHpriority journalprotein aggregationprotein denaturationprotein interactionprotein stabilityprotein unfoldingthermostabilityX ray crystallographyArtigo10.1016/j.colsurfb.2013.06.050WOS:000324897900074Acesso restrito2-s2.0-8488099276667053670106620870000-0002-6205-9441