Las serín proteasas están ampliamente distribuidas y pueden ser encontradas en todos los reinos. ... more Las serín proteasas están ampliamente distribuidas y pueden ser encontradas en todos los reinos. Se han propuesto serín proteasas de plantas como agentes anticoagulantes y antiplaquetarios. En el presente trabajo reportamos la actividad fibrinogenolítica y antiplaquetaria de una proteasa del tipo subtilisina de Solanum tuberosum (StSBTc-3), previamente identificada y purificada en nuestro laboratorio. Los resultados obtenidos muestran que StSBTc-3 es capaz de degradar todas las cadenas del fibrinógeno y redisolver el coagulo de fibrina en forma dosis dependiente. También se realizó una caracterización bioquímica de la proteasa en estudio. El pH óptimo para la actividad fibrinogenolítica fue 8 y la temperatura óptima fue de 37 C. StSBTc-3 presentó un amplio rango de actividad en función del pH (5 a 12). En cuanto a la temperatura, presentó actividad entre 30 C 60 C. También se determinaron siete sitios de clivado de la cadena B de la insulina. Se realizaron ensayos para determinar la...
Boletin Latinoamericano y del Caribe de Plantas Medicinales y Aromaticas
Previous reports have been described the purification and characterization of two potato aspartic... more Previous reports have been described the purification and characterization of two potato aspartic proteases, StAP1 and StAP3 with antimicrobial activity towards plant pathogenic microorganisms (Phytophthora infestans y Fusarium solani). On the other hand, we have cloned and expressed in E. coli a domain of these proteins named Plant Specific Insert (StAPs-PSIr). This domain has high structural homology with a proteins family with antimicrobial activity, named saposin-like proteins family. As well as StAPs and its structural homologous, StAP-PSIr has antimicrobial activity, specifically on plant pathogens. In this study we analysed the citotoxic activity of StAPs and StAP-PSIr on three bacterial strains (Escherichia coli, Bacillus cereus and Staphylococcus aureus) and human erythrocytes cultures. The results obtained here show that StAPs and StAP-PSIr are able to diminish the viability of bacteria cultures in a dose-dependent manner; however, this effect was not observed on the human...
This report describes the purification of an aspartic protease (salpichroin) from ripe fruits of ... more This report describes the purification of an aspartic protease (salpichroin) from ripe fruits of Salpichroa origanifolia (Solanaceae) starting with precipitation using organic solvents and anion-exchange chromatography with 32.1% recovery and 13.4-fold purification. SDS-PAGE and zymograms of this enzyme showed a single band corresponding to an apparent molecular mass of approximately 32 kDa. The biochemical and kinetic characterization of the pure enzyme showed an acidic behavior with an optimal pH value around 3.0-4.5 with hemoglobin and 5.5-6.0 with casein. Salpichroin activity was inhibited by pepstatin but not by phenylmethylsulfonyl fluoride, E-64, EDTA or 1,10-phenanthroline, thus suggesting an aspartic protease behavior. Salpichroin hydrolyzed natural substrates, such as casein and hemoglobin, with high specific activity. Kinetic studies conducted with the synthetic peptide H-Pro-Thr-Glu-Phe-p-(NO2)-Phe-Arg-Leu-OH showed lower affinity (Km 494 µM) than other representative as...
Plant-specific insert domain (PSI) is a region of approximately 100 amino acid residues present i... more Plant-specific insert domain (PSI) is a region of approximately 100 amino acid residues present in most plant aspartic protease (AP) precursors. PSI is not a true saposin domain; it is the exchange of the N- and C-terminal portions of the saposin like domain. Hence, PSI is called a swaposin domain. Here, we report the cloned, heterologous expression and purification of PSI from StAsp 1 (Solanum tuberosum aspartic protease 1), called StAsp-PSI. Results obtained here show that StAsp-PSI is able to kill spores of two potato pathogens in a dose-dependent manner without any deleterious effect on plant cells. As reported for StAPs (S. tuberosum aspartic proteases), the StAsp-PSI ability to kill microbial pathogens is dependent on the direct interaction of the protein with the microbial cell wall/or membrane, leading to increased permeability and lysis. Additionally, we demonstrated that, like proteins of the SAPLIP family, StAsp-PSI and StAPs are cytotoxic to Gram-negative and Gram-positive bacteria in a dose dependent manner. The amino acid residues conserved in SP_B (pulmonary surfactant protein B) and StAsp-PSI could explain the cytotoxic activity exerted by StAsp-PSI and StAPs against Gram-positive bacteria. These results and data previously reported suggest that the presence of the PSI domain in mature StAPs could be related to their antimicrobial activity.
International Journal of Biological Macromolecules, 2007
Specific roles of glycosylation appear to be protein-dependent. Plant aspartic proteases (APs) co... more Specific roles of glycosylation appear to be protein-dependent. Plant aspartic proteases (APs) contain two or more consensus N-glycosylation sites; however, the importance of them is not well understood. StAPs (Solanum tuberosum aspartic proteases) are bifunctional proteins with both proteolytic and antimicrobial activities. These proteins are accumulated into the intercellular washing fluid of potato tubers and leaves after wounding or infection. In this paper we investigated the importance of glycosylation on the StAPs apoplast accumulation, biochemical parameters, and fungicidal activity. Assays to evaluate the importance of StAPs glycosylation groups by using glycosylation inhibitors demonstrate that carbohydrate portions are essential to StAPs accumulation into the apoplast of tubers and leaves after wounding or detachment, respectively. Bifunctional activity of StAPs is differentially affected by this post-translational modification. Results obtained show that not significant changes were produced in the physicochemical properties after StAPs deglycosylation (pH and thermal-optimum activity and index of protein surface hydrophobicity). Otherwise, StAPs antifungal activity is affected by deglycosylation. Deglycosylated StAPs (dgStAPs) fungicidal activity is lower than native StAPs at all concentrations and times assayed. In summary, glycosylation has not a significant role on the StAPs conformational structure. However, it is involved in the StAPs subcellular accumulation and antifungal activity suggesting that it could be necessary for StAPs membrane and/or protein interactions and subsequently its biological function(s).
Biochimica et Biophysica Acta (BBA) - Molecular and Cell Biology of Lipids, 2011
Potato aspartic proteases (StAPs) and their swaposin domain (StAsp-PSI) are proteins with cytotox... more Potato aspartic proteases (StAPs) and their swaposin domain (StAsp-PSI) are proteins with cytotoxic activity which involves plasma membrane destabilization. The ability of these proteins to produce cell death varies with the cellular type. Therefore, StAPs and StAsp-PSI selective cytotoxicity could be attributed to the different membrane lipid compositions of target cells. In this work we investigate the possible mechanism by which StAPs and StAsp-PSI produce selective membrane destabilization. Results obtained from leakage assays show that StAsp-PSI is a potent inducer of the leakage of LUVs containing anionic phospholipids, especially those containing phosphatidylglycerol. Based in these results, we suggest that the cytotoxic activity of StAsp-PSI on pathogenic microorganisms could be mediated by the attraction between the exposed positive domains of StAsp-PSI and the negatively charged microorganism membrane. On the other hand, our circular dichroism spectroscopic measurements and analysis by size exclusion chromatography and followed by electrophoresis, indicate that hydrophobic environment is necessary to StAsp-PSI oligomerization and both StAsp-PSI disulfide bounds and membrane with negative charged phospholipids are required by StAsp-PSI to produce membrane destabilization and then induce cell death in tumors and microorganism cell targets. Additionally, we demonstrate that the presence of cholesterol into the LUV membranes strongly diminishes the capacity of StAsp-PSI to produce leakage. This result suggests that the lack of hemolytic and cytotoxic activities on human lymphocytes of StAsp-PSI/StAPs may be partly due by the presence of cholesterol in these cell membrane types.
Las serín proteasas están ampliamente distribuidas y pueden ser encontradas en todos los reinos. ... more Las serín proteasas están ampliamente distribuidas y pueden ser encontradas en todos los reinos. Se han propuesto serín proteasas de plantas como agentes anticoagulantes y antiplaquetarios. En el presente trabajo reportamos la actividad fibrinogenolítica y antiplaquetaria de una proteasa del tipo subtilisina de Solanum tuberosum (StSBTc-3), previamente identificada y purificada en nuestro laboratorio. Los resultados obtenidos muestran que StSBTc-3 es capaz de degradar todas las cadenas del fibrinógeno y redisolver el coagulo de fibrina en forma dosis dependiente. También se realizó una caracterización bioquímica de la proteasa en estudio. El pH óptimo para la actividad fibrinogenolítica fue 8 y la temperatura óptima fue de 37 C. StSBTc-3 presentó un amplio rango de actividad en función del pH (5 a 12). En cuanto a la temperatura, presentó actividad entre 30 C 60 C. También se determinaron siete sitios de clivado de la cadena B de la insulina. Se realizaron ensayos para determinar la...
Boletin Latinoamericano y del Caribe de Plantas Medicinales y Aromaticas
Previous reports have been described the purification and characterization of two potato aspartic... more Previous reports have been described the purification and characterization of two potato aspartic proteases, StAP1 and StAP3 with antimicrobial activity towards plant pathogenic microorganisms (Phytophthora infestans y Fusarium solani). On the other hand, we have cloned and expressed in E. coli a domain of these proteins named Plant Specific Insert (StAPs-PSIr). This domain has high structural homology with a proteins family with antimicrobial activity, named saposin-like proteins family. As well as StAPs and its structural homologous, StAP-PSIr has antimicrobial activity, specifically on plant pathogens. In this study we analysed the citotoxic activity of StAPs and StAP-PSIr on three bacterial strains (Escherichia coli, Bacillus cereus and Staphylococcus aureus) and human erythrocytes cultures. The results obtained here show that StAPs and StAP-PSIr are able to diminish the viability of bacteria cultures in a dose-dependent manner; however, this effect was not observed on the human...
This report describes the purification of an aspartic protease (salpichroin) from ripe fruits of ... more This report describes the purification of an aspartic protease (salpichroin) from ripe fruits of Salpichroa origanifolia (Solanaceae) starting with precipitation using organic solvents and anion-exchange chromatography with 32.1% recovery and 13.4-fold purification. SDS-PAGE and zymograms of this enzyme showed a single band corresponding to an apparent molecular mass of approximately 32 kDa. The biochemical and kinetic characterization of the pure enzyme showed an acidic behavior with an optimal pH value around 3.0-4.5 with hemoglobin and 5.5-6.0 with casein. Salpichroin activity was inhibited by pepstatin but not by phenylmethylsulfonyl fluoride, E-64, EDTA or 1,10-phenanthroline, thus suggesting an aspartic protease behavior. Salpichroin hydrolyzed natural substrates, such as casein and hemoglobin, with high specific activity. Kinetic studies conducted with the synthetic peptide H-Pro-Thr-Glu-Phe-p-(NO2)-Phe-Arg-Leu-OH showed lower affinity (Km 494 µM) than other representative as...
Plant-specific insert domain (PSI) is a region of approximately 100 amino acid residues present i... more Plant-specific insert domain (PSI) is a region of approximately 100 amino acid residues present in most plant aspartic protease (AP) precursors. PSI is not a true saposin domain; it is the exchange of the N- and C-terminal portions of the saposin like domain. Hence, PSI is called a swaposin domain. Here, we report the cloned, heterologous expression and purification of PSI from StAsp 1 (Solanum tuberosum aspartic protease 1), called StAsp-PSI. Results obtained here show that StAsp-PSI is able to kill spores of two potato pathogens in a dose-dependent manner without any deleterious effect on plant cells. As reported for StAPs (S. tuberosum aspartic proteases), the StAsp-PSI ability to kill microbial pathogens is dependent on the direct interaction of the protein with the microbial cell wall/or membrane, leading to increased permeability and lysis. Additionally, we demonstrated that, like proteins of the SAPLIP family, StAsp-PSI and StAPs are cytotoxic to Gram-negative and Gram-positive bacteria in a dose dependent manner. The amino acid residues conserved in SP_B (pulmonary surfactant protein B) and StAsp-PSI could explain the cytotoxic activity exerted by StAsp-PSI and StAPs against Gram-positive bacteria. These results and data previously reported suggest that the presence of the PSI domain in mature StAPs could be related to their antimicrobial activity.
International Journal of Biological Macromolecules, 2007
Specific roles of glycosylation appear to be protein-dependent. Plant aspartic proteases (APs) co... more Specific roles of glycosylation appear to be protein-dependent. Plant aspartic proteases (APs) contain two or more consensus N-glycosylation sites; however, the importance of them is not well understood. StAPs (Solanum tuberosum aspartic proteases) are bifunctional proteins with both proteolytic and antimicrobial activities. These proteins are accumulated into the intercellular washing fluid of potato tubers and leaves after wounding or infection. In this paper we investigated the importance of glycosylation on the StAPs apoplast accumulation, biochemical parameters, and fungicidal activity. Assays to evaluate the importance of StAPs glycosylation groups by using glycosylation inhibitors demonstrate that carbohydrate portions are essential to StAPs accumulation into the apoplast of tubers and leaves after wounding or detachment, respectively. Bifunctional activity of StAPs is differentially affected by this post-translational modification. Results obtained show that not significant changes were produced in the physicochemical properties after StAPs deglycosylation (pH and thermal-optimum activity and index of protein surface hydrophobicity). Otherwise, StAPs antifungal activity is affected by deglycosylation. Deglycosylated StAPs (dgStAPs) fungicidal activity is lower than native StAPs at all concentrations and times assayed. In summary, glycosylation has not a significant role on the StAPs conformational structure. However, it is involved in the StAPs subcellular accumulation and antifungal activity suggesting that it could be necessary for StAPs membrane and/or protein interactions and subsequently its biological function(s).
Biochimica et Biophysica Acta (BBA) - Molecular and Cell Biology of Lipids, 2011
Potato aspartic proteases (StAPs) and their swaposin domain (StAsp-PSI) are proteins with cytotox... more Potato aspartic proteases (StAPs) and their swaposin domain (StAsp-PSI) are proteins with cytotoxic activity which involves plasma membrane destabilization. The ability of these proteins to produce cell death varies with the cellular type. Therefore, StAPs and StAsp-PSI selective cytotoxicity could be attributed to the different membrane lipid compositions of target cells. In this work we investigate the possible mechanism by which StAPs and StAsp-PSI produce selective membrane destabilization. Results obtained from leakage assays show that StAsp-PSI is a potent inducer of the leakage of LUVs containing anionic phospholipids, especially those containing phosphatidylglycerol. Based in these results, we suggest that the cytotoxic activity of StAsp-PSI on pathogenic microorganisms could be mediated by the attraction between the exposed positive domains of StAsp-PSI and the negatively charged microorganism membrane. On the other hand, our circular dichroism spectroscopic measurements and analysis by size exclusion chromatography and followed by electrophoresis, indicate that hydrophobic environment is necessary to StAsp-PSI oligomerization and both StAsp-PSI disulfide bounds and membrane with negative charged phospholipids are required by StAsp-PSI to produce membrane destabilization and then induce cell death in tumors and microorganism cell targets. Additionally, we demonstrate that the presence of cholesterol into the LUV membranes strongly diminishes the capacity of StAsp-PSI to produce leakage. This result suggests that the lack of hemolytic and cytotoxic activities on human lymphocytes of StAsp-PSI/StAPs may be partly due by the presence of cholesterol in these cell membrane types.
Uploads
Papers by Fernando Muñoz