RESUMO
In this work we communicate the heterologous expression of a laccase from Coriolopsis gallica in Pichia pastoris. This enzyme has been reported to efficiently degrade a variety of pollutants such as industrial dyes. The expression strategy included using a previously reported modified α-factor preproleader for enhanced secretion and pAOX1, a methanol-responsive promoter. Methanol concentration, copper salts concentration and temperature were varied in order to enhance laccase expression in this heterologous system. A volumetric activity of 250 U/L was achieved after 12-day culture in Fernbach flasks. The protein was recovered from the supernatant and purified, obtaining a preparation with 90% electrophoretic purity. The catalytic constants of the recombinant enzyme are almost identical to the fungal enzyme, thus rendering this system a useful tool for protein engineering of laccase from C. gallica.
Assuntos
Coriolaceae/genética , Proteínas Fúngicas , Expressão Gênica , Lacase , Coriolaceae/enzimologia , Proteínas Fúngicas/biossíntese , Proteínas Fúngicas/química , Proteínas Fúngicas/genética , Lacase/biossíntese , Lacase/química , Lacase/genética , Pichia/genética , Pichia/metabolismo , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/química , Proteínas Recombinantes/genéticaRESUMO
ETHNOPHARMACOLOGY RELEVANCE: Galphimia glauca (Malpighiaceae) is a Mexican plant popularly used as a tranquilizer in the treatment of nervous system disorders, although it is also used to treat other common illnesses. AIM OF THE STUDY: The aim of this investigation is to find out if populations of Galphimia glauca collected in different regions and ecosystems in Mexico actually belong to the same species by using the contemporary technique of DNA barcodes. Our previous metabolic profiling study demonstrates that different collections of this plant obtained from various geographical areas exhibited diverse chemical profiles in terms of the active compounds named Galphimines. We expected the DNA barcodes apart from indicating the different species of Galphimia would indicate the active populations. MATERIALS AND METHODS: We employed matK, rpoC1 and rbcL DNA barcodes to indicate the different species. Furthermore to investigate the possible impact of the several different ecosystems where the seven populations were collected, thin layer chromatography was employed to create a partial chemical profile, which was then compared with the metabolic profiles obtained by (1)H-NMR and multivariate data analysis. RESULTS AND CONCLUSIONS: This study showed that the seven populations here analyzed contain at least three different species of the genus Galphimia, although each individual population is homogeneous. Interestingly our TLC analysis clearly showed that the active populations displayed a distinctively unique chemical profile. This work also showed that the use of DNA barcodes combined with chemical profile analysis is an excellent approach to solve the problems of quality control in the development of Galphimia-based medicines as well as for any breeding programs for this species.
Assuntos
DNA de Plantas/genética , Galphimia/genética , Filogenia , Ansiolíticos , Código de Barras de DNA Taxonômico , Hipnóticos e Sedativos , Análise dos Mínimos Quadrados , México , Folhas de Planta , Proteínas de Plantas/genéticaRESUMO
Bacillus thuringiensis subsp. israelensis produces crystal proteins, Cry (4Aa, 4Ba, 10Aa, and 11Aa) and Cyt (1Aa and 2Ba) proteins, toxic to mosquito vectors of human diseases. Cyt1Aa overcomes insect resistance to Cry11Aa and Cry4 toxins and synergizes the toxicity of these toxins. However, the molecular mechanism of synergism remains unsolved. Here, we provide evidence that Cyt1Aa functions as a receptor of Cry11Aa. Sequential-binding analysis of Cyt1Aa and Cry11Aa revealed that Cyt1Aa binding to Aedes aegypti brush border membrane vesicles enhanced the binding of biotinylated-Cry11Aa. The Cyt1Aa- and Cry11Aa-binding epitopes were mapped by means of the yeast two-hybrid system, peptide arrays, and heterologous competition assays with synthetic peptides. Two exposed regions in Cyt1Aa, loop beta6-alphaE and part of beta7, bind Cry11Aa. On the other side, Cry11Aa binds Cyt1Aa proteins by means of domain II-loop alpha8 and beta-4, which are also involved in midgut receptor interaction. Characterization of single-point mutations in Cry11Aa and Cyt1Aa revealed key Cry11Aa (S259 and E266) and Cyt1Aa (K198, E204 and K225) residues involved in the interaction of both proteins and in synergism. Additionally, a Cyt1Aa loop beta6-alphaE mutant (K198A) with enhanced synergism to Cry11Aa was isolated. Data provided here strongly indicates that Cyt1Aa synergizes or suppresses resistance to Cry11Aa toxin by functioning as a membrane-bound receptor. Bacillus thuringiensis subsp. israelensis is a highly effective pathogenic bacterium because it produces a toxin and also its functional receptor, promoting toxin binding to the target membrane and causing toxicity.