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

Carvalho, José Wilson Pires; Alves, Fernanda; Batista, Tatiana; Carvalho, Francisco Adriano de Oliveira; Santiago, Patrícia S.; Tabak, Marcel

doi:10.1016/j.colsurfb.2013.06.050

Cited by 12 publications

(14 citation statements)

References 25 publications

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“…At pH 5.0, oxy-HbGp presents a broad transition peak with a higher temperature (T m 688C), as compared with pH 7.0, together with an exothermic peak above T m associated to protein aggregation (T agg 708C), even in the absence of DTAB ( Figures 4C and 4D). This is consistent with calorimetric data reported recently by Carvalho et al 14,15 The addition of DTAB decreases the T m values from 68 to 568C upon increasing surfactant from 0.0 to 1.0 mmol/L ( Figure 4D), while the T agg values are shifted from 78 to around 698C. The HSDSC curves profile, at pH 7.0, in the presence of DTAB, has a similar behavior when compared with pH 5.0 without DTAB (as observed for the presence of the exothermic peak), suggesting similarities on the hemoglobin denaturation/aggregation processes.…”

Section: Dtab-oxy-hbgp Interaction By Calorimetry 205supporting

confidence: 95%

“…8 More recently, further studies were performed with oxy-and cyanomet-HbGp in the pH range from 5.0 to 7.0. 14,15 The DSC thermograms were characterized by a single endothermic peak with a critical temperature of 60.2 6 0.28C for oxy-HbGp, while two clearly defined peaks with critical temperatures of 59.0 6 0.1 and 65.2 6 0.28C were observed for cyanometHbGp, at pH 7.0. In acidic pH, oxy-and cyanomet-HbGp are more stable showing higher critical temperatures and aggregation.…”

Section: Introductionmentioning

confidence: 99%

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Interaction of cationic dodecyl‐trimethyl‐ammonium bromide with oxy‐HbGp by isothermal titration and differential scanning calorimetric studies: Effect of proximity of isoelectric point

Alves

Carvalho

et al. 2016

Biopolymers

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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 ≈ 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 Tm 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.

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Section: Dtab-oxy-hbgp Interaction By Calorimetry 205supporting

confidence: 95%

Section: Introductionmentioning

confidence: 99%

Interaction of cationic dodecyl‐trimethyl‐ammonium bromide with oxy‐HbGp by isothermal titration and differential scanning calorimetric studies: Effect of proximity of isoelectric point

Alves

Carvalho

et al. 2016

Biopolymers

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“…In Figure 3, the plots of DH, as a function of SDS concentration, at pH 7.0, from 25 to 40 C, are shown. 26 According to this study, at pH 7.0, oxy-HbGp undergoes complete oligomeric dissociation with increase of temperature, in the presence of SDS. DH values versus SDS concentration were calculated by integrating the heat flow peaks versus time (data not shown).…”

Section: Effect Of Temperature On the Sds-oxy-hbgp Interactionsmentioning

confidence: 83%

Glossoscolex paulistus extracellular hemoglobin (HbGp) oligomeric dissociation upon interaction with sodium dodecyl sulfate: Isothermal titration calorimetry (ITC)

Alves

Carvalho

et al. 2014

Biopolymers

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Annelid erythrocruorins are respiratory proteins with high cooperativity and low autoxidation rates. The giant extracellular hemoglobin of the earthworm, Glossoscolex paulistus (HbGp), has a molecular mass of 3.6 MDa. In this work, isothermal titration calorimetry (ITC), together with DLS and fluorescence emission have been used to investigate the interaction of SDS with the HbGp in the oxy-form, at pH 7.0. Our ITC and DLS results show that addition of SDS induces oxy-HbGp oligomeric dissociation, while a small amount of protein aggregation is observed only by DLS. Moreover, the oligomeric dissociation process is favored at lower protein concentrations. The temperature effect does not influence significantly the interaction of SDS with the hemoglobin, due to the similarities presented by the critical aggregation concentration (cac) and critical micelle concentration (cmc') for the mixtures. The increase of oxy-HbGp concentration leads to a slight variation of the cac values for the SDS-oxy-HbGp mixture, attributed mainly to the noncooperative electrostatic binding of surfactant to protein. However, the cmc' values increase considerably, associated to a more cooperative hydrophobic binding. Complementary pyrene fluorescence emission studies show formation of pre-micellar structures of the mixture already at lower SDS concentrations. This study opens the possibility of the evaluation of the surfactant effect on the hemoglobin stability by ITC, which is made for the first time with this extracellular hemoglobin.

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“…Nas Figuras 20A e 20C são mostradas as curvas de SAXS, com os respectivos ajustes obtidos usando o programa GNOM, para a oxi-HbGp 3,0 mg/mL, pH 7,0, na presença de 0,2 ( Essa diminuição do I(0) pode ser atribuída à dissociação oligomérica da oxi-HbGp, que nesse caso, é seguida pela desnaturação [67]. Entretanto, as curvas de p(r) não mostram a contribuição de partículas pequenas com o aumento da temperatura (Fig.…”

Section: Ph 70unclassified

“…Dessa forma, é provável que a existência de uma pequena fração de proteína dissociada não seja detectada devido à concentração de proteína ser relativamente alta, assim como por uma limitação da técnica que possui baixa resolução. constantes, sugerindo que a oxi-HbGp, no meio ácido, na presença de SDS, não sofre dissociação oligomérica antes de desnaturar e formar agregados, com o aumento da temperatura [67].…”

Section: Ph 70unclassified

Estudo da estabilidade térmica da hemoglobina extracelular gigante de Glossoscolex paulistus (HbGp): efeitos do estado de oxidação do ferro do grupo heme, pH e presença de surfactante

Carvalho¹

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AgradecimentosAgradeço! Aos meus pais Maria Gorete Pires Carvalho e José de Ribamar Gomes Carvalho e a minha esposa Sumária Sousa e Silva pela dedicação, carinho, motivação nas horas mais difíceis, sem eles não teria forças para seguir essa jornada; Ao Professor Marcel Tabak por sua orientação e pelos laços de amizade e respeito que se formaram nesta convivência e também pela oportunidade de poder desenvolver esse trabalho;A Fundação de Amparo a Pesquisa do Estado de São Paulo (FAPESP) pela bolsa de doutorado;Aos meus irmãos Genilson, Genilda e Gesilda pelo apoio, carinho e afeto que temos e pelas palavras amigas;Às minhas tias Eva (segunda mãe), Maria da Guia e Raimunda Teresa e os primos (as) Rita de Kássia, Karla Karolina, Raiza, Rairone, Railson, Amanda e Constância pelo apoio e carinho que sempre me motiva; Aos meus amigos de laboratório Adriano, Fernanda, Ana Eliza, Diógenes e Ezer Biazin, pelo apoio moral e pela contribuição direta e indireta na minha formação e neste trabalho. Obrigado em especial a vocês Adriano e Ezer Biazin; Aos meus amigos Orlando, Ana Célia, Adriane, Washington, Alexandre, Tairo, Adriana, Elenice, Jairo e Edvan pelas discussões bem humoradas e pela amizade; Aos professores Dr.(a) (s) Leandro R. S. Barbosa (IF-USP), Rosângela Itri (IF-USP), Patríca S. Santiago (UNESP-Registro), Carlos Ernesto Garrido Salmon (USP-Riberão Preto) e Tatiana Batista (UEL-PR) pelas discussões e colaborações durante meu curso de doutorado, que foi muito importante para minha formação; Ao Ezér Biazin, técnico do laboratório, por toda ajuda na parte instrumental e que sem nenhuma dúvida foi muito importante para o bom desenvolvimento deste trabalho e pela amizade que se construiu nestes cinco anos; A Andressa Patrícia Alves Pinto, técnica do laboratório de biofísica do IFSC por toda ajuda nos experimentos de CD que foi muito importante para o bom desenvolvimento deste trabalho; Ao Laboratório Nacional de Luz Síncrotron (LNLS), em especial ao Dr. Mateus Cardoso, coordenador da linha SAXS2, pelo auxílio na realização das medidas de SAXS;Ao pessoal da pós-graduação, Sílvia, Andréia e Gustavo, por toda a atenção, carinho e pelos bons serviços prestados;A dona Suely e seu José de Ribamar pelos conselhos e apoio nos momentos difíceis.

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

Cited by 12 publications

References 25 publications

Interaction of cationic dodecyl‐trimethyl‐ammonium bromide with oxy‐HbGp by isothermal titration and differential scanning calorimetric studies: Effect of proximity of isoelectric point

Interaction of cationic dodecyl‐trimethyl‐ammonium bromide with oxy‐HbGp by isothermal titration and differential scanning calorimetric studies: Effect of proximity of isoelectric point

Glossoscolex paulistus extracellular hemoglobin (HbGp) oligomeric dissociation upon interaction with sodium dodecyl sulfate: Isothermal titration calorimetry (ITC)

Estudo da estabilidade térmica da hemoglobina extracelular gigante de Glossoscolex paulistus (HbGp): efeitos do estado de oxidação do ferro do grupo heme, pH e presença de surfactante

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