ROSA MARIA CHURA CHAMBI

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Agora exibindo 1 - 10 de 17
  • Artigo IPEN-doc 25863
    Protein refolding based on high hydrostatic pressure and alkaline pH
    2019 - CHURA-CHAMBI, ROSA M.; SILVA, CLEIDE M.R. da; PEREIRA, LENNON R.; BARTOLINI, PAOLO; FERREIRA, LUIS C. de S.; MORGANTI, LIGIA
    In this study we evaluated the association of high hydrostatic pressure (HHP) and alkaline pH as a minimally denaturing condition for the solubilization of inclusion bodies (IBs) generated by recombinant proteins expressed by Escherichia coli strains. The method was successfully applied to a recombinant form of the dengue virus (DENV) non-structural protein 1 (NS1). The minimal pH for IBs solubilization at 1 bar was 12 while a pH of 10 was sufficient for solubilization at HHP: 2.4 kbar for 90 min and 0.4 kbar for 14 h 30 min. An optimal refolding condition was achieved by compression of IBs at HHP and pH 10.5 in the presence of arginine, oxidized and reduced glutathiones, providing much higher yields (up to 8-fold) than association of HHP and GdnHCl via an established protocol. The refolded NS1, 109 ± 9.5 mg/L bacterial culture was recovered mainly as monomer and dimer, corresponding up to 90% of the total protein and remaining immunologically active. The proposed conditions represent an alternative for the refolding of immunologically active recombinant proteins expressed as IBs.
  • Artigo IPEN-doc 25191
    Association of high pressure and alkaline condition for solubilization of inclusion bodies and refolding of the NS1 protein from zika virus
    2018 - SILVA, CLEIDE M.R. da; CHURA-CHAMBI, ROSA M.; PEREIRA, LENNON R.; CORDEIRO, YRAIMA; FERREIRA, LUIS C. de S.; MORGANTI, LIGIA
    Background: Proteins in inclusion bodies (IBs) present native-like secondary structures. However, chaotropic agents at denaturing concentrations, which are widely used for IB solubilization and subsequent refolding, unfold these secondary structures. Removal of the chaotropes frequently causes reaggregation and poor recovery of bioactive proteins. High hydrostatic pressure (HHP) and alkaline pH are two conditions that, in the presence of low level of chaotropes, have been described as non-denaturing solubilization agents. In the present study we evaluated the strategy of combination of HHP and alkaline pH on the solubilization of IB using as a model an antigenic form of the zika virus (ZIKV) non-structural 1 (NS1) protein. Results: Pressure-treatment (2.4 kbar) of NS1-IBs at a pH of 11.0 induced a low degree of NS1 unfolding and led to solubilization of the IBs, mainly into monomers. After dialysis at pH 8.5, NS1 was refolded and formed soluble oligomers. High (up to 68 mg/liter) NS1 concentrations were obtained by solubilization of NS1-IBs at pH 11 in the presence of arginine (Arg) with a final yield of approximately 80% of total protein content. The process proved to be efficient, quick and did not require further purification steps. Refolded NS1 preserved biological features regarding reactivity with antigen-specific antibodies, including sera of ZIKV-infected patients. The method resulted in an increase of approximately 30-fold over conventional IB solubilization-refolding methods. Conclusions: The present results represent an innovative non-denaturing protein refolding process by means of the concomitant use of HHP and alkaline pH. Application of the reported method allowed the recovery of ZIKV NS1 at a condition that maintained the antigenic properties of the protein.
  • Artigo IPEN-doc 25079
    Leptospira interrogans thermolysin refolded at high pressure and alkaline pH displays proteolytic activity against complement C3
    2018 - CHURA-CHAMBI, ROSA M.; FRAGA, TATIANA R.; SILVA, LUDMILA B. da; YAMAMOTO, BRUNO B.; ISAAC, LOURDES; BARBOSA, ANGELA S.; MORGANTI, LIGIA
    Enzymes from the thermolysin family are crucial factors in the pathogenesis of several diseases caused by bacteria and are potential targets for therapeutic interventions. Thermolysin encoded by the gene LIC13322 of the causative agent of leptospirosis, Leptospira interrogans, was shown to cleave proteins from the Complement System. However, the production of this recombinant protein using traditional refolding processes with high levels of denaturing reagents for thermolysin inclusion bodies (TL-IBs) solubilization results in poor recovery and low proteolytic activity probably due to improper refolding of the protein. Based on the assumption that leptospiral proteases play a crucial role during infection, the aim of this work was to obtain a functional recombinant thermolysin for future studies on the role of these metalloproteases on leptospiral infection. The association of high hydrostatic pressure (HHP) and alkaline pH was utilized for thermolysin refolding. Incubation of a suspension of TL-IBs at HHP and a pH of 11.0 is non-denaturing but effective for thermolysin solubilization. Soluble protein does not reaggregate by dialysis to pH 8.0. A volumetric yield of 46 mg thermolysin/L of bacterial culture and a yield of near 100% in relation to the total thermolysin present in TL-IBs were obtained. SEC-purified thermolysin suffers fragmentation, likely due to autoproteolysis and presents proteolytic activity against complement C3 α-chain, possibly by a generation of a C3b-like molecule. The proteolytic activity of thermolysin against C3 was time and dose-dependent. The experience gained in this study shall help to establish efficient HHP-based processes for refolding of bioactive proteins from IBs.
  • Artigo IPEN-doc 22822
    Structural studies of the protein endostatin in fusion with BAX BH3 death domain, a hybrid that presents enhanced antitumoral activity
    2017 - CHURA-CHAMBI, ROSA M.; ARCURI, HELEN A.; LINO, FELIPE; VERSATI, NATAN; PALMA, MARIO S.; FAVARO, DENIZE C.; MORGANTI, LIGIA
    Endostatin (ES) is an antiangiogenic protein that exhibits antitumor activity in animal models. However, the activity observed in animals was not observed in human clinical trials. ES-BAX is a fusion protein composed of two functional domains: ES, which presents specificity and is internalized by activated endothelial cells and the proapoptotic BH3 domain of the protein BAX, a peptide inductor of cellular death when internalized. We have previously shown (Chura-Chambi et al., Cell Death Dis, 5, e1371, 2014) that ES-BAX presents improved antitumor activity in relation to wild-type ES. Secondary and tertiary structures of ES-BAX are similar to ES, as indicated by homology-modeling studies and molecular dynamics simulations. Tryptophan intrinsic fluorescence and circular dichroism spectroscopy corroborate these data. 15N HSQC NMR indicates that ES-BAX is structured, but some ES residues have suffered chemical shift perturbations, suggesting that the BH3 peptide interacts with some parts of the ES protein. ES and ES-BAX present similar stability to thermal denaturation. The production of stable hybrid proteins can be a new approach to the development of therapeutic agents presenting specificity for tumoral endothelium and improved antitumor effect.
  • Artigo IPEN-doc 20281
    VapC from the leptospiral VapBC toxin-antitoxin module display ribonuclease activity on the initiator tRNA
    2014 - LOPES, ALEXANDRE P.Y.; LOPES, LUANA M.; FRAGA, TATIANA R.; CHURA-CHAMBI, ROSA M.; SANSON, ANDRE L.; CHENG, ELISABETH; NAKAJIMA, ERIKA; MORGANTI, LIGIA; MARTINS, ELIZABETH A.L.
  • Artigo IPEN-doc 20203
    Investigation on solubilization protocols in the refolding of the thiredoxin TsnC from Xylella fastidiosa by high hydrostatic pressure approach
    2015 - LEMKE, LAURA S.; CHURA-CHAMBI, ROSA M.; RODRIGUES, DANIELLA; CUSSIOL, JOSE R.R.; MALAVASI, NATALIA V.; ALEGRIA, THIAGO G.P.; SOARES NETTO, LUIS E.; MORGANTI, LIGIA
  • Artigo IPEN-doc 20121
    Improving the therapeutic potential of endostatin by fusing it the BAX BH3 death domain
    2014 - CHURA-CHAMBI, R.M.; BELLINI, M.H.; JACYSYN, J.F.; ANDRADE, L.N.; MEDINA, L.P.; PRIETO da SILVA, A.R.B.; AMARANTE-MENDES, G.P.; MONGANTI, L.
    Endostatin (ES) inhibits angiogenesis, reducing tumor growth in animal models. However, it has low therapeutic effect in human clinical trials. BAX is a member of the BCL-2 family of proteins; its proapoptotic (BH3) domain interacts with other members of the family in the cytoplasm, to induce apoptosis. Here, we fused the BAX BH3 domain with murine ES, to enhance ES potency. Endothelial cells specifically internalize the fusion protein ES-BAX. The presence of the BAX domain enhances endothelial cell death by apoptosis by 1.8-fold and diminishes microvessel outgrowth in the rat aortic ring assay by 6.5-fold. Daily injections of 15 lg of ES-BAX/g in tumor-bearing mice reduce tumor weight by 86.9% as compared with ES-treated animals. Co-immunoprecipitation assays confirmed that ES-BAX interacts with members of the BCL-2 family. Also, ES interacts with BCL-2, BCL-XL, and BAK in endothelial cell lysates, suggesting a potential new mechanism for the apoptosis induction by ES. The superiority of the ES-BAX antiangiogenic effect indicates that this fusion protein could be a promising therapeutic alternative to treat cancer.
  • Artigo IPEN-doc 20095
    Effect of pressure on refolding of recombinant pentameric cholera toxin B
    2014 - RODRIGUES, D.; FARINHA-ARCIERI, L.E.; VENTURA, A.M.; CHURA-CHAMBI, R.M.; MALAVASI, R.V.; LEMKE, L.S.; GUIMARAES, J.S.; HO, P.L.; MORGANTI, L.
    The production of recombinant proteins is an essential tool for the expansion of modern biological research and biotechnology. The expression of heterologous proteins in Escherichia coli often results in an incomplete folding process that leads to the accumulation of inclusion bodies (IB), aggregates that hold a certain degree of native-like secondary structure. High hydrostatic pressure (HHP) impairs intermolecular hydrophobic and electrostatic interactions, leading to dissociation of aggregates under non-denaturing conditions and is therefore a useful tool to solubilize proteins for posterior refolding. Cholera toxin (CT) is composed of a non-toxic pentamer of B subunits (CTB), a useful adjuvant in vaccines, and a toxic subunit A (CTA). We studied the process of refolding of CTB using HHP. HHP was shown to be effective for dissociation of CTB monomers from IB. Posterior incubation at atmospheric pressure of concentrated CTB (1 mg/ml) is necessary for the association of the monomers. Pentameric CTB was obtained when suspensions of CTB IB were compressed at 2.4 kbar for 16 h in the presence of Tween 20 and incubated at 1 bar for 120 h. Soluble and biologically active pentameric CTB was obtained, with a yield of 213 mg CTB/liter of culture. The experience gained in this study can be important to improve the refolding of proteins with quaternary structure.
  • Resumo IPEN-doc 18947
    Application of high hydrostatic pressure for recovery of biologically active cruzain from recombinant inclusion bodies
    2011 - CHAMBI, ROSA M.C.; LEMKE, LAURA S.; VALLEJO, NATALIA M.; JULIANO NETO, LUIZ; MORGANTI, LIGIA
  • Artigo IPEN-doc 19586
    The effect of temperature on protein refolding at high pressure enhanced green fluorescent protein as a model
    2014 - MALAVASI, N.V.; CORDEIRO, Y.; RODRIGUES, D.; CHURA-CHAMBI, R.M.; LEMKE, L.S.; MORGANTI, L.