کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
599853 1454293 2013 10 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Sodium dodecyl sulfate (SDS) effect on the thermal stability of oxy-HbGp: Dynamic light scattering (DLS) and small angle X-ray scattering (SAXS) studies
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی شیمی کلوئیدی و سطحی
پیش نمایش صفحه اول مقاله
Sodium dodecyl sulfate (SDS) effect on the thermal stability of oxy-HbGp: Dynamic light scattering (DLS) and small angle X-ray scattering (SAXS) studies
چکیده انگلیسی


• HbGp is a multi-subunit oligomeric hemoglobin, with a high molecular mass of 3.6 MDa.
• HbGp-SDS interaction leads to complete protein oligomeric dissociation, at pH 7.0.
• Oxy-HbGp SDS-induced thermal aggregation depends on protein concentration and pH.
• HbGp-SDS interaction at pH 5.0 is characterized by aggregation at lower temperatures.
• At alkaline pH 9.0 only oligomeric dissociation is observed in oxy-HbGp-SDS system.

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 SDS. 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 °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 0.5 mg/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) × 10−4 s−1, respectively, at 0.6 mmol/L SDS. However, at 3.0 mg/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 3.0 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.

Figure optionsDownload as PowerPoint slide

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Colloids and Surfaces B: Biointerfaces - Volume 111, 1 November 2013, Pages 561–570
نویسندگان
, , , , , ,