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Application of acid proteases from nepenthes in hydrogen/deuterium exchange.
Darebná, Petra ; Man, Petr (advisor) ; Stráňava, Martin (referee)
Application of acid proteases from Nepenthes in hydrogen/deuterium exchange Petra Darebná (Department of Biochemistry, Faculty of Science, Charles University in Prague, Czech Republic) Nepenthes are mostly found in Borneo and Sumatra. They are one of a few carnivorous plants which produce its own proteolytic enzymes (nepenthesin I and nepenthesin II), which provide an alternative source of nitrogen and other nutrients in case that these plants grow in a soil which lacks such nutrients. These aspartate proteases are capable of proteolysis at a very low pH of a digestive gastrovascular cavity fluid after catching insects and in a cooperation with other proteins participating in digestion process. Processing of a digestive fluid, isolated from a digestive gastrovascular cavities of carnivorous plants of the Nepenthes genus and its possible application as a tool in a protein study using hydrogen/deuterium exchange were done in this thesis. Isolates of the digestive fluids were purified from coarse-grained impurities by centrifugation, activated by acidification and concentrated by ultrafiltration. The amount of proteins and their protein profile were monitored and an activity of acidic proteases was determined by enzymatic assay. Consequently, using LC-MS/MS and model proteins, the cleavage preferences...
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Preparation and use of acid proteases for digestion in H/D exchange.
Kukla, Jan ; Man, Petr (advisor) ; Pompach, Petr (referee)
- 5 - Abstract Hydrogen/deuterium exchange coupled to mass spectrometry (HX-MS) utilizes the spontaneous exchange of protein backbone amide hydrogens for deuterium atoms from solution to gain information about changes in protein structure. To localize these changes to specific areas of the protein, enzymatic digestion by aspartate proteases is used. The proteases' ability to produce small overlapping peptides and to provide full sequence coverage of the studied protein is essential for pinpointing the protein regions of interest. In this study recombinant proteases nepenthesin I (Nepenthes gracilis) and rhizopuspepsin (Rhizopus chinensis) were prepared and compared to commercially available proteases porcine pepsin A and aspergillopepsin (Aspergillus saitoi). The comparison was performed using various activity assays, where the effects of pH, temperature and denaturing and reducing agents on the activity of the proteases were studied. All four proteases were also immobilized on a polymeric resin POROS and their activity in an online HX-MS digestion setup was tested using myoglobin as a model substrate.
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Analysis of Histone Deacetylase 6/Kinesin Interactions
Nedvědová, Jana ; Bařinka, Cyril (advisor) ; Pavlíček, Jiří (referee)
Intracellular transport is provided by two major types of molecular motors kinesins and cytoplasmic dynein. Kinesin-1 is a molecular motor that transports molecules and organelles along microtubule tracks anterogradely. Specific protein-protein interactions are required to activate kinesin-1 as the free kinesin exist in an autoinhibited state. The activation of kinesin-1 induces its conformational change, enables microtubule binding and ATP hydrolysis necessary for the directional cargo transport. HDAC6 is a multifunctional protein composed of several domains. It plays an important role in many microtubule dependent processes as HDAC6 is a major tubulin deacetylase. It has been shown that HDAC6 manipulation (inhibition/genetic ablation) affects transport along microtubules but the exact mechanisms are unknown. The effect can be caused either by deacetylation microtubules or direct interaction with molecular motors. This thesis is focused on characterization of interactions between kinesin-1 and HDAC6 that have not been described so far. To this end, we expressed and purified various constructs of kinesin-1 and HDAC6 and tested their interactions by microscale thermophoresis (MST) and hydrogen deuterium exchange (HDX) to determine affinity and interaction sites, respectively. MST data revealed that...
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Recombinant expression of chloride channel from E. coliand its structure characterization
Hausner, Jiří ; Man, Petr (advisor) ; Vrbacký, Marek (referee)
Chloride channel family has been shown to play a significant role in physiological homeostasis processes. The function mechanism of these proteins has not yet been clearly understood. Their deficiency or mutation causes serious human illnesses. Our understanding of the chloride channels' transporting mechanisms can lead to better treatment of these illnesses. As mammalian chloride channels are difficult to prepare in laboratory, the experiments are usually done on homologous chloride channels from prokaryotic organisms. The structures of prokaryotic chloride channels have been solved and moreover they are produced with high yields. Most experiments currently use protein crystallography and provide a static picture of the system. This thesis is focused on the study of structural changes of an E. coli chloride channel using hydrogen/deuterium exchange. This method enables us to monitor dynamic conformation changes dependent on pH and exchanged ions. The measurements were done for the protonated (pH 4.5) and deprotonated state (pH 7.5) and/or in the presence of various anions: Cl− , SCN− , I− , F− , TAR. (tartaric anion). The obtained results justified the theories explaining the function of chloride channel as Cl− /H+ antiporter and provided new findings. Subject words biochemistry, protein...
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Preparation and use of acid proteases for digestion in H/D exchange.
Kukla, Jan ; Man, Petr (advisor) ; Pompach, Petr (referee)
- 5 - Abstract Hydrogen/deuterium exchange coupled to mass spectrometry (HX-MS) utilizes the spontaneous exchange of protein backbone amide hydrogens for deuterium atoms from solution to gain information about changes in protein structure. To localize these changes to specific areas of the protein, enzymatic digestion by aspartate proteases is used. The proteases' ability to produce small overlapping peptides and to provide full sequence coverage of the studied protein is essential for pinpointing the protein regions of interest. In this study recombinant proteases nepenthesin I (Nepenthes gracilis) and rhizopuspepsin (Rhizopus chinensis) were prepared and compared to commercially available proteases porcine pepsin A and aspergillopepsin (Aspergillus saitoi). The comparison was performed using various activity assays, where the effects of pH, temperature and denaturing and reducing agents on the activity of the proteases were studied. All four proteases were also immobilized on a polymeric resin POROS and their activity in an online HX-MS digestion setup was tested using myoglobin as a model substrate.
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Study of the interaction between DNA and transcription factors using mass spectrometry.
Slavata, Lukáš ; Man, Petr (advisor) ; Obšil, Tomáš (referee)
Transcription factors play crucial regulatory role within the cell and the entire multicellular organism. The important factor is its ability to interact with other regulatory proteins and DNA. Despite the fact that a large part of the interaction network is already documented, detailed information on the structure and dynamics of protein-protein and protein-DNA complexes is still scarce. In this thesis we focused on the possibility of studying conformational changes given by the transcription factor-DNA complex formation using the methods of structural mass spectrometry: hydrogen/deuterium exchange and chemical crosslinking. As a model, we chose a transcription factor FOXO4 which DNA binding domain is structurally well characterized both in free form and in the complex with DNA.
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Application of acid proteases from nepenthes in hydrogen/deuterium exchange.
Darebná, Petra ; Man, Petr (advisor) ; Stráňava, Martin (referee)
Application of acid proteases from Nepenthes in hydrogen/deuterium exchange Petra Darebná (Department of Biochemistry, Faculty of Science, Charles University in Prague, Czech Republic) Nepenthes are mostly found in Borneo and Sumatra. They are one of a few carnivorous plants which produce its own proteolytic enzymes (nepenthesin I and nepenthesin II), which provide an alternative source of nitrogen and other nutrients in case that these plants grow in a soil which lacks such nutrients. These aspartate proteases are capable of proteolysis at a very low pH of a digestive gastrovascular cavity fluid after catching insects and in a cooperation with other proteins participating in digestion process. Processing of a digestive fluid, isolated from a digestive gastrovascular cavities of carnivorous plants of the Nepenthes genus and its possible application as a tool in a protein study using hydrogen/deuterium exchange were done in this thesis. Isolates of the digestive fluids were purified from coarse-grained impurities by centrifugation, activated by acidification and concentrated by ultrafiltration. The amount of proteins and their protein profile were monitored and an activity of acidic proteases was determined by enzymatic assay. Consequently, using LC-MS/MS and model proteins, the cleavage preferences...
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