Exfoliative Toxins of Staphylococcus aureus

Virulent strains of Staphylococcus aureus secrete exfoliative toxins (ETs) that cause the loss of cell‐cell adhesion in the superficial epidermis. S. aureus ETs are serine proteases, which exhibit exquisite substrate specificity, and their mechanisms of action are extremely complex. To date, four different serotypes of ETs have been identified and three of them (ETA, ETB and ETD) are associated with toxin‐mediated staphylococcal syndromes related to human infections leading to diseases of medical and veterinary importance

Exfoliative toxin E, a new Staphylococcus aureus virulence factor with host-specific activity

Exfoliative toxin E, a new [i]Staphylococcus aureus[/i] virulence factor with host-specific activity. Microbes, 15e Congrès National de la SF

Preparation and characterization of monomodal grapevine virus a capsid protein

Grapevine virus A (GVA), a flexible filament of approximately 800 nm in length is composed of capsid subunits that spontaneously assembles around a positive sense genomic RNA. In addition to encapsidation, plant viruses capsid proteins (CPs) participate in other processes throughout infection and GVA CP is involved in cell-to-cell translocation of the virus. A protocol was developed to obtain low-molecular weight GVA-CP that is not prone to aggregation and spontaneous assembly and this was characterized by circular dichroism and dynamic light scattering. These results indicate the suitably of GVA-CP for X-ray crystallographic and NMR studies that should lead to the elucidation of the first three-dimensional structure of a flexible filamentous virus from the Betaflexiviridae family

Crystal structure of Jararacussin-I: The highly negatively charged catalytic interface contributes to macromolecular selectivity in snake venom thrombin-like enzymes

Submitted by Luciane Willcox ([email protected]) on 2016-09-02T18:33:57Z No. of bitstreams: 1 Crystal structure of Jararacussin-I.pdf: 356808 bytes, checksum: cd01e76570df32e71244d77604645768 (MD5)Approved for entry into archive by Luciane Willcox ([email protected]) on 2016-09-02T19:10:05Z (GMT) No. of bitstreams: 1 Crystal structure of Jararacussin-I.pdf: 356808 bytes, checksum: cd01e76570df32e71244d77604645768 (MD5)Made available in DSpace on 2016-09-02T19:10:05Z (GMT). No. of bitstreams: 1 Crystal structure of Jararacussin-I.pdf: 356808 bytes, checksum: cd01e76570df32e71244d77604645768 (MD5) Previous issue date: 2012-11-08FAPESP, CNPq, TWAS, DAAD, CAPESUniversidade Estadual Paulista. Instituto de Biociências Letras e Ciências Exatas. Departamento de Física. Centro Multiusuário de Inovação Biomolecular, São Jose do Rio Preto, SP, Brasil.Centro Nacional de Pesquisa em Energia e Materiais. Laboratório Nacional de Biociências. Campinas, SP, Brasil / Fundação Oswaldo Cruz. Instituto Carlos Chagas. Curitiba, PR, Brasil.Universidade Estadual Paulista. Instituto de Biociências Letras e Ciências Exatas. Departamento de Física. Centro Multiusuário de Inovação Biomolecular, São Jose do Rio Preto, SP, Brasil.Universidade Estadual Paulista. Instituto de Biociências Letras e Ciências Exatas. Departamento de Física. Centro Multiusuário de Inovação Biomolecular, São Jose do Rio Preto, SP, Brasil.Universidade Estadual Paulista. Instituto de Biociências Letras e Ciências Exatas. Departamento de Física. Centro Multiusuário de Inovação Biomolecular, São Jose do Rio Preto, SP, Brasil.Centro Nacional de Pesquisa em Energia e Materiais. Laboratório Nacional de Biociências. Campinas, SP, Brasil.Universidade Estadual Paulista. Instituto de Biociências Letras e Ciências Exatas. Departamento de Física. Centro Multiusuário de Inovação Biomolecular, São Jose do Rio Preto, SP, Brasil.Snake venom serine proteinases (SVSPs) are hemostatically active toxins that perturb the maintenance and regulation of both the blood coagulation cascade and fibrinolytic feedback system at specific points, and hence, are widely used as tools in pharmacological and clinical diagnosis. The crystal structure of a thrombin-like enzyme (TLE) from Bothrops jararacussu venom (Jararacussin-I) was determined at 2.48 Å resolution. This is the first crystal structure of a TLE and allows structural comparisons with both the Agkistrodon contortrix contortrix Protein C Activator and the Trimeresurus stejnegeri plasminogen activator. Despite the highly conserved overall fold, significant differences in the amino acid compositions and three-dimensional conformations of the loops surrounding the active site significantly alter the molecular topography and charge distribution profile of the catalytic interface. In contrast to other SVSPs, the catalytic interface of Jararacussin-I is highly negatively charged, which contributes to its unique macromolecular selectivity

Exfoliative toxin E, a new Staphylococcus aureus virulence factor with host-specific activity

Exfoliative toxin E, a new [i]Staphylococcus aureus[/i] virulence factor with host-specific activity. Microbes, 15e Congrès National de la SF

Exfoliative toxin E, a new Staphylococcus aureus virulence factor with host-specific activity

Exfoliative toxin E, a new [i]Staphylococcus aureus[/i] virulence factor with host-specific activity. Microbes, 15e Congrès National de la SF

Crystal structure of Staphylococcus aureus exfoliative toxin D-like protein: Structural basis for the high specificity of exfoliative toxins

Submitted by Luciane Willcox ([email protected]) on 2016-10-13T18:59:54Z No. of bitstreams: 1 Crystal structure of Staphylococcus aureus.pdf: 1416047 bytes, checksum: 53f125cbb3d4cf997582ffceb05b570e (MD5)Approved for entry into archive by Luciane Willcox ([email protected]) on 2016-10-13T19:07:57Z (GMT) No. of bitstreams: 1 Crystal structure of Staphylococcus aureus.pdf: 1416047 bytes, checksum: 53f125cbb3d4cf997582ffceb05b570e (MD5)Made available in DSpace on 2016-10-13T19:07:57Z (GMT). No. of bitstreams: 1 Crystal structure of Staphylococcus aureus.pdf: 1416047 bytes, checksum: 53f125cbb3d4cf997582ffceb05b570e (MD5) Previous issue date: 2015-08-20Universidade Estadual Paulista. Instituto de Biociências, Letras e Ciências Exatas. Departamento de Física. Centro Multiusuário para Inovação Biomolecular. São José do Rio Preto, SP, Brasil.Fundação Oswaldo Cruz. Instituto Carlos Chagas. Curitiba, PR, Brasil.Universidade Estadual Paulista. Instituto de Biociências, Letras e Ciências Exatas. Departamento de Física. Centro Multiusuário para Inovação Biomolecular. São José do Rio Preto, SP, Brasil.Universidade Estadual Paulista. Instituto de Biociências, Letras e Ciências Exatas. Departamento de Física. Centro Multiusuário para Inovação Biomolecular. São José do Rio Preto, SP, Brasil.Universidade Estadual Paulista. Instituto de Biociências, Letras e Ciências Exatas. Departamento de Física. Centro Multiusuário para Inovação Biomolecular. São José do Rio Preto, SP, Brasil.Centro Nacional de Pesquisa em Energia e Materiais. Laboratório Nacional de Laboratório de Ciência e Tecnologia de Bioetanol. Campinas, SP, Brasil.Universidade Federal de Minas Gerais. Instituto de Ciências Biológicas. Laboratório de Genética Celular e Molecular. Belo Horizonte, MG, Brasil / French National Institute for Agricultural Research. Laboratoire du Science et Technologie du Lait et de l’œuf. Rennes, France / Agrocampus Ouest. Rennes, France.Universidade Federal de Minas Gerais. Instituto de Ciências Biológicas. Laboratório de Genética Celular e Molecular. Belo Horizonte, MG, Brasil.Universidade Federal de Minas Gerais. Instituto de Ciências Biológicas. Laboratório de Genética Celular e Molecular. Belo Horizonte, MG, Brasil.Centro Nacional de Pesquisa em Energia e Materiais. Laboratório Nacional de Biosciências Brasileiras. Campinas, SP, Brasil.Universidade Estadual Paulista. Instituto de Biociências, Letras e Ciências Exatas. Departamento de Física. Centro Multiusuário para Inovação Biomolecular. São José do Rio Preto, SP, Brasil.French National Institute for Agricultural Research. Laboratory of Science and Technology of Milk and Egg. Rennes, France / Agrocampus Ouest. Rennes, FranceExfoliative toxins are serine proteases secreted by Staphylococcus aureus that are associated with toxin-mediated staphylococcal syndromes. To date, four different serotypes of exfoliative toxins have been identified and 3 of them (ETA, ETB, and ETD) are linked to human infection. Among these toxins, only the ETD structure remained unknown, limiting our understanding of the structural determinants for the functional differentiation between these toxins. We recently identified an ETD-like protein associated to S. aureus strains involved in mild mastitis in sheep. The crystal structure of this ETD-like protein was determined at 1.95 Å resolution and the structural analysis provide insights into the oligomerization, stability and specificity and enabled a comprehensive structural comparison with ETA and ETB. Despite the highly conserved molecular architecture, significant differences in the composition of the loops and in both the N- and C-terminal α-helices seem to define ETD-like specificity. Molecular dynamics simulations indicate that these regions defining ET specificity present different degrees of flexibility and may undergo conformational changes upon substrate recognition and binding. DLS and AUC experiments indicated that the ETD-like is monomeric in solution whereas it is present as a dimer in the asymmetric unit indicating that oligomerization is not related to functional differentiation among these toxins. Differential scanning calorimetry and circular dichroism assays demonstrated an endothermic transition centered at 52 °C, and an exothermic aggregation in temperatures up to 64 °C. All these together provide insights about the mode of action of a toxin often secreted in syndromes that are not associated with either ETA or ETB

Natural Products Isolated from Oriental Medicinal Herbs Inactivate Zika Virus

Zika virus (ZIKV) has been associated with serious health conditions, and an intense search to discover different ways to prevent and treat ZIKV infection is underway. Berberine and emodin possess several pharmacological properties and have been shown to be particularly effective against the entry and replication of several viruses. We show that emodin and berberine trigger a virucidal effect on ZIKV. When the virus was exposed to 160 µM of berberine, a reduction of 77.6% in the infectivity was observed; when emodin was used (40 µM), this reduction was approximately 83.3%. Dynamic light scattering data showed that both compounds significantly reduce the hydrodynamic radius of virus particle in solution. We report here that berberine and emodin, two natural compounds, have strong virucidal effect in Zika virus