Cysteine peptidases from Phytomonas serpens: biochemical and immunological approaches |
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Authors: | Camila GR Elias Ana Carolina Aor Roberta S Valle Claudia M d'Avila-Levy Marta H Branquinha & André LS Santos |
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Institution: | Laboratório de Estudos Integrados em Bioquímica Microbiana, Departamento de Microbiologia Geral, Instituto de Microbiologia Prof. Paulo de Góes (IMPPG), Centro de Ciências da Saúde (CCS), Bloco E-subsolo, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ, Brazil;;Laboratório de Biologia Molecular e Doenças Endêmicas, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, RJ, Brazil;and;Laboratório de Bioquímica de Proteases, Departamento de Microbiologia Geral, Instituto de Microbiologia Prof. Paulo de Góes (IMPPG), Centro de Ciências da Saúde (CCS), Bloco I, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ, Brazil |
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Abstract: | Phytomonas serpens , a phytoflagellate trypanosomatid, shares common antigens with Trypanosoma cruzi . In the present work, we compared the hydrolytic capability of cysteine peptidases in both trypanosomatids. Trypanosoma cruzi epimastigotes presented a 10-fold higher efficiency in hydrolyzing the cysteine peptidase substrate Z-Phe-Arg-AMC than P. serpens promastigotes. Moreover, two weak cysteine-type gelatinolytic activities were detected in P. serpens , while a strong 50-kDa cysteine peptidase was observed in T. cruzi . Cysteine peptidase activities were detected at twofold higher levels in the cytoplasmic fraction when compared with the membrane-rich or the content released from P. serpens . The cysteine peptidase secreted by P. serpens cleaved several proteinaceous substrates. Corroborating these findings, the cellular distribution of the cruzipain-like molecules in P. serpens was attested through immunocytochemistry analysis. Gold particles were observed in all cellular compartments, including the cytoplasm, plasma membrane, flagellum, flagellar membrane and flagellar pocket. Interestingly, some gold particles were visualized free in the flagellar pocket, suggesting the release of the cruzipain-like molecule. The antigenic properties of the cruzipain-like molecules of P. serpens were also analyzed. Interestingly, sera from chagasic patients recognized both cellular and extracellular antigens of P. serpens , including the cruzipain-like molecule. These results point to the use of P. serpens antigens, especially the cruzipain-like cysteine-peptidases, as an alternative vaccination approach to T. cruzi infection. |
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Keywords: | Phytomonas serpens Trypanosoma cruzi cruzipain cysteine peptidases chagasic patient sera |
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