Análise proteômica diferencial de Acidithiobacillus ferrooxidans em resposta aos sulfetos minerais calcopirita e bornita e efeito de uma proteína recombinante de A. ferrooxidans LR contendo cisteína na oxidação bacteriana da calcopirita
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Data
2008-07-24
Autores
Novello, Ana Paula Felício [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
Acidithiobacillus ferrooxidans (A. ferrooxidans) é uma bactéria quimioautotrófica capaz de oxidar íon ferroso ou sulfetos minerais para a obtenção de energia. Bornita e calcopirita são dois sulfetos de cobre que possuem a mesma composição elementar, mas diferem na susceptibilidade para a biolixiviação. Este trabalho teve por objetivo a análise proteômica diferencial de A. ferrooxidans em resposta à mudança do substrato íon ferroso para os sulfetos minerais calcopirita ou bornita. Comparativamente a outras doze linhagens de A. ferrooxidans, a linhagem LR apresentou uma das maiores velocidades de oxidação sobre ambos os minerais em experimentos de respirometria, sendo selecionada para ser utilizada na análise proteômica. Respostas de células de A. ferrooxidans LR à bornita ou calcopirita foram investigadas utilizando-se 2D-PAGE e espectrometria de massas. O perfil de proteínas totais de células livres expostas aos minerais por 24 ou 48 horas foi comparado com o perfil das células não expostas (controle). Para bornita, detectou-se indução na síntese das proteínas chaperonina (groEL), antioxidante da família AhpC/Tsa e aldeído desidrogenase, enquanto que proteína de domínio radical SAM, frutose-1-6-bifosfatase, proteína de choque térmico HslU, carboidrato quinase, ribulose bifosfato carboxilase e proteínas ribossomais S2 e L25 tiveram sua síntese reprimida. Alterações opostas na expressão protéica foram detectadas para duas formas da fructose-bifosfato aldolase, as quais apresentaram valores distintos de ponto isoelétrico, sugerindo o envolvimento de modificações pós-traducionais desta proteína em A. ferrooxidans em resposta à bornita. Todas as alterações detectadas para a bornita não foram observadas na presença de calcopirita, não sendo detectada pela abordagem utilizada qualquer alteração significativa em células expostas a este mineral...
Acidithiobacillus ferrooxidans (A.ferrooxidans) is a chemoautotrophic bacterium able to oxidize ferrous iron or mineral sulfides to obtain energy. Bornite and chalcopyrite are two copper sulfides having the same elemental composition but differ in relation to the susceptibility for bioleaching process. The aim of this work was to perform a differential proteomic analysis of the A. ferrooxidans response to the exchange of ferrous ion as an energetic substrate to the mineral sulfides chalcopyrite or bornite. Among twelve A. ferrooxidans strains, the LR strain presented one of the highest oxidative rates on both minerals by respirometric assays, and was chosen for the proteomic analysis studies. The bacterium responses to bornite or chalcopyrite were investigated by 2D-PAGE and mass spectrometry. The total protein profiles of cells exposed to bornite or chalcopyrite for 24 or 48 hours were compared to the one of control not exposed to minerals. For bornite, were detected an induction for the proteins chaperonin (groEL), AhpC/Tsa family antioxidant and aldehyde dehydrogenase, whereas the proteins radical SAM domain, fructose-1-6- bisphosphatase, carbohydrate kinase, HslU heat shock protein, ribulose bisphosphate carboxylase and the ribosomal proteins S2 and L25 were repressed. For the protein fructosebisphosphate aldolase two forms having distinct isoelectric points were observed suggesting pos-translational modification of this protein in the A. ferrooxidans response to bornite. No significant alteration of the protein expression was detected for cells exposed to chalcopyrite. Therefore, the proteomic analyses show that these minerals lead to distinct cellular responses in A. ferrooxidans. Distinct responses were detected by proteomic analysis of the periplasmic fraction for chalcopyrite-attached cells in relation to non-attached cells. The analysis by 2D showed four proteins that presented... (Complete abstract click electronic access below)
Acidithiobacillus ferrooxidans (A.ferrooxidans) is a chemoautotrophic bacterium able to oxidize ferrous iron or mineral sulfides to obtain energy. Bornite and chalcopyrite are two copper sulfides having the same elemental composition but differ in relation to the susceptibility for bioleaching process. The aim of this work was to perform a differential proteomic analysis of the A. ferrooxidans response to the exchange of ferrous ion as an energetic substrate to the mineral sulfides chalcopyrite or bornite. Among twelve A. ferrooxidans strains, the LR strain presented one of the highest oxidative rates on both minerals by respirometric assays, and was chosen for the proteomic analysis studies. The bacterium responses to bornite or chalcopyrite were investigated by 2D-PAGE and mass spectrometry. The total protein profiles of cells exposed to bornite or chalcopyrite for 24 or 48 hours were compared to the one of control not exposed to minerals. For bornite, were detected an induction for the proteins chaperonin (groEL), AhpC/Tsa family antioxidant and aldehyde dehydrogenase, whereas the proteins radical SAM domain, fructose-1-6- bisphosphatase, carbohydrate kinase, HslU heat shock protein, ribulose bisphosphate carboxylase and the ribosomal proteins S2 and L25 were repressed. For the protein fructosebisphosphate aldolase two forms having distinct isoelectric points were observed suggesting pos-translational modification of this protein in the A. ferrooxidans response to bornite. No significant alteration of the protein expression was detected for cells exposed to chalcopyrite. Therefore, the proteomic analyses show that these minerals lead to distinct cellular responses in A. ferrooxidans. Distinct responses were detected by proteomic analysis of the periplasmic fraction for chalcopyrite-attached cells in relation to non-attached cells. The analysis by 2D showed four proteins that presented... (Complete abstract click electronic access below)
Descrição
Palavras-chave
Biotecnologia, Proteínas, Bactéria acidofílica, Proteins
Como citar
NOVELLO, Ana Paula Felício. Análise proteômica diferencial de Acidithiobacillus ferrooxidans em resposta aos sulfetos minerais calcopirita e bornita e efeito de uma proteína recombinante de A. ferrooxidans LR contendo cisteína na oxidação bacteriana da calcopirita. 2008. 189 f. Tese (doutorado) - Universidade Estadual Paulista, Instituto de Química, 2008.