Síntese, estudos estruturais e de atividades biológicas de metalopeptídeos estruturalmente derivados da toxina CcdB
Carregando...
Data
2019-02-27
Autores
Proft, Caio Silveira Fermiano de [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Universidade Estadual Paulista (Unesp)
Resumo
O presente trabalho descreve o estudo de um mimético da proteína CcdB, o CcdBSG-2, para verificar a possibilidade de formação de um complexo metálico com o lantanídeo Térbio (III) e com o íon metálico Cobre (II), bem como avaliar o potencial dos complexos em inibir a atividade das enzimas bacterianas DNA-girase e Topoisomerase IV. Este peptídeo foi sintetizado pela metodologia de síntese em fase sólida (SPFS), purificado por cromatografia líquida de alta eficiência (CLAE) e identificado por espectrometria de massas (LC/ESI-MS). Posteriormente o peptídeo foi complexado com 3 equivalentes molares de Cu(II) e Tb(III) e acompanhou-se as alterações nos espectros de absorção e emissão de fluorescência do peptídeo e espectroscopia de luminescência após a adição dos metais. Estes mesmos estudos espectroscópicos foram realizados em função do tempo para verificar o intervalo necessário para a formação de cada complexo metal-peptídeo. Foram realizados também estudos de caracterização estrutural por espectroscopia de dicroísmo circular, avaliando o peptídeo na presença e ausência dos metais. Para avaliar o potencial de inibição dos peptídeos, utilizou-se ensaios de eletroforese em gel de agarose frente as enzimas DNA girase e Topoisomerase IV e ensaios de crescimento bacteriano em meio líquido frente as bactérias Escherichia coli enterohemorrágica e Staphylococcus aureus. Ambos os testes para avaliar o potencial de inibição mostraram que os metalopeptídeos Tb(III)-CcdBSG-2 e Cu(II)-CcdBSG-2 apresentam uma atividade cerca de três vezes maior que o peptídeo CcdBSG-2 na ausência do metal. Estes resultados importantes indicam que o aumento do potencial inibitório está relacionado com um sinergismo criado entre os metais e CcdBSG-2.
The present work describes the study of a mimetic of the protein CcdB, the CcdBSG-2, to verify the possibility of formation of a metallic complex with the lanthanide Terbium(III) and with the metallic ion Copper (II), as well as to evaluate the potential of the complexes in inhibiting the activity of bacterial enzymes DNA-gyrase and Topoisomerase IV. This peptide was synthesized by the methodology of solid phase peptide synthesis (SPPS), purified by high performance liquid chromatography (HPLC) and identified by mass spectrometry (LC / ESI-MS). Later the peptide was complexed with 3 molar equivalents of Cu (II) and Tb (III), followed by changes in the spectra of absorption and emission of fluorescence of the peptide and luminescence spectroscopy after the addition of the metals. These same spectroscopic studies were performed as a function of time to verify the interval required for the formation of each metal-peptide complex. Structural characterization studies were also performed by circular dichroism spectroscopy, evaluating the peptide in the presence and absence of metals. To evaluate the inhibition potential, electrophoresis and bacterial growth assays were used in liquid medium against the peptides produced. Both tests to assess the inhibition potential showed that theTb (III) -CcdBSG-2 and Cu (II) -CcdBSG-2 metallopeptides exhibit about three times greater activity than the CcdBSG-2 peptide in the absence of the metal. These important results indicate that the increase in inhibitory potential is related to a synergismcreated between the metals and CcdBSG-2.
The present work describes the study of a mimetic of the protein CcdB, the CcdBSG-2, to verify the possibility of formation of a metallic complex with the lanthanide Terbium(III) and with the metallic ion Copper (II), as well as to evaluate the potential of the complexes in inhibiting the activity of bacterial enzymes DNA-gyrase and Topoisomerase IV. This peptide was synthesized by the methodology of solid phase peptide synthesis (SPPS), purified by high performance liquid chromatography (HPLC) and identified by mass spectrometry (LC / ESI-MS). Later the peptide was complexed with 3 molar equivalents of Cu (II) and Tb (III), followed by changes in the spectra of absorption and emission of fluorescence of the peptide and luminescence spectroscopy after the addition of the metals. These same spectroscopic studies were performed as a function of time to verify the interval required for the formation of each metal-peptide complex. Structural characterization studies were also performed by circular dichroism spectroscopy, evaluating the peptide in the presence and absence of metals. To evaluate the inhibition potential, electrophoresis and bacterial growth assays were used in liquid medium against the peptides produced. Both tests to assess the inhibition potential showed that theTb (III) -CcdBSG-2 and Cu (II) -CcdBSG-2 metallopeptides exhibit about three times greater activity than the CcdBSG-2 peptide in the absence of the metal. These important results indicate that the increase in inhibitory potential is related to a synergismcreated between the metals and CcdBSG-2.
Descrição
Palavras-chave
CcdB, DNA girase, Inibidores peptídicos de topoisomerases, Metalopeptídeos