A novel chlorpyrifos hydrolase CPD from Paracoccus sp. TRP: molecular cloning, characterization and catalytic mechanism

Background: Biodegradation is a reliable approach for efficiently eliminating persistent pollutants such as chlorpyrifos. Despite many bacteria or fungi isolated from contaminated environment and capable of degrading chlorpyrifos, limited enzymes responsible for its degradation have been identified, let alone the catalytic mechanism of the enzymes. Results: In present study, the gene cpd encoding a chlorpyrifos hydrolase was cloned by analysis of genomic sequence of Paracoccus sp. TRP. Phylogenetic analysis and BLAST indicated that CPD was a novel member of organophosphate hydrolases. The purified CPD enzyme, with conserved catalytic triad (Ser155-Asp251-His281) and motif Gly-Asp-Ser-Ala-Gly, was significantly inhibited by PMSF, a serine modifier. Molecular docking between CPD and chlorpyrifos showed that Ser155 was adjacent to chlorpyrifos, which indicated that Ser155 may be the active amino acid involved in chlorpyrifos degradation. This speculation was confirmed by site-directed mutagenesis of Ser155Ala accounting for the decreased activity of CPD towards chlorpyrifos. According to the key role of Ser155 in chlorpyrifos degradation and molecular docking conformation, the nucleophilic catalytic mechanism for chlorpyrifos degradation by CPD was proposed. Conclusion: The novel enzyme CPD was capable of hydrolyze chlorpyrifos and Ser155 played key role during degradation of chlorpyrifos.

VI congresso brasileiro de ciências sociais e humanas em saúde da Abrasco / VI Brazilian Congress of social sciences and humanities in health Abrasco

O Congresso aconteceu na UERJ, e fala sobre a mobilização social; a luta pela democratização da comunicação; a Comissão da Verdade da Reforma Sanitária; resultados da indução ao consumo, entre outros temas. O presidente da Abrasco considera este Congresso um produtor de subsídios para melhoria das políticas de saúde e das práticas dos serviços de saúde. entrevistados: Kenneth Rochel Camargo Junior, Roseni Pinheiro, Luis Eugenio de Souza, Madel Luz, Carine Abreu, Laura da Maia, Sharlene Goulart, Maria Salete Bessa Jorge, Mardenia Gomes, Ana Maria Tambellini, Modesto da Silveira, Umberto Trigueiros, Jean Wyllys, Janine Cardoso, Aurea Pitta, Orlando Guilhon, Rogério Lannes, Paulo Vaz, Paula Sibilia, Beto Novaes, Carlos Minayo, Ziadir Francisco Coutinho, Eduardo Thielen...