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Preparation of a plasmid, its expression and preliminary isolation of MafK protein - the interacting partner of heme sensor Bach1
Mihalčin, Peter ; Martínková, Markéta (advisor) ; Stráňava, Martin (referee)
Bakalárska práca Abstract Heme-sensing proteins are heme proteins to which heme serves as a signalling molecule. Association or dissociation of heme moiety and heme-sensing proteins influences various physiological functions, such as enzyme activity or gene expression regulated by these heme-sensing proteins. The main object of this thesis is heme-sensing protein Bach1 and its interaction partner, transcription factor MafK. Bach1 refers to the group of transcription factors involved in repression of gene expression. The target genes of Bach1 regulation are hemeoxygenase genes. Hemeoxygenase controls the excess free heme degradation. Due to the excess of free heme in the cell, Bach1-heme interaction inactivates Bach1 controlled repression of hemeoxygenase resulting in the free heme degradation. In the state of physiological free heme concentration, Bach1-heme interaction does not occur and activated Bach1 represses the hemeoxygenase expression via binding to the target gene enhancers. Bach1 is incapable of making efficient Bach1-DNA bonding by itself, therefore the transcription factor MafK is essential. Protein MafK modulates the Bach1-DNA binding by making the heterodimer formation Bach1-MafK, which binds to DNA. The first aim of this thesis is to summarize the recent knowledge about transcriptional...
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Influence of V-ATPase inhibitors on chemoresistant neuroblastoma lines in vitro
Honzejková, Karolína ; Eckschlager, Tomáš (advisor) ; Martínková, Markéta (referee)
Tumor diseases are one of the most common causes of death worldwide. Despite the great advances in therapy in the last fifty years, this is still a serious health problem. Therefore, great efforts are still concentrated on development of new anti-cancer drugs and therapeutic approaches. Neuroblastoma (NBL) is the most common tumor in infants and the fourth most common in children. Successful treatment is greatly complicated by its heterogeneity. Chemoresistance is an undesirable phenomenon of chemotherapy. One of the chemoresistance mechanisms is the accumulation of weakly basic anticancer drugs in lysosomes. This work deals with the measurement of lysosomal uptake of these compounds in neuroblastoma cell lines UKF-NB-4 and derived, ellipticine-resistant, line (UKF-NB- 4ELLI ) under different conditions. A method for determining the cell lysosomal capacity (volume) by measuring fluorescence intensity of lysosome-specific LTR dye was introduced and the ability of bafilomycin A, a V-ATPase inhibitor, to potentiate the effects of an anticancer agent ellipticine by inhibiting its lysosomal accumulation was investigated. Keywords: neuroblastoma, lysosome, vacuolar ATPase, multidrug resistance
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Molecular mechanisms of signal transduction in model heme-containing oxygen sensor proteins
Stráňava, Martin ; Martínková, Markéta (advisor) ; Obšil, Tomáš (referee) ; Macek, Tomáš (referee)
EN Heme containing gas sensor proteins play important role in bacterial physiology in regulating many processes such as cell differentiation, virulence, biofilm formation or intercellular communication. For their structure, typical modular architecture is characteristic where various sensor domains (usually at the N-terminus) regulate the activity of the catalytic or functional domains (usually at the C-terminus). In this dissertation thesis, we focused on three representatives from the group of oxygen sensing proteins, namely histidine kinase AfGcHK, diguanylate cyclase YddV, phosphodiesterase EcDOS and also on protein RR, which is the interaction partner of AfGcHK. The main aim of the thesis was to study intra-protein/inter-domain signal transduction in two representatives of heme sensor proteins with a globin fold of the sensor domain (AfGcHK, YddV) and in one representative with PAS fold of the sensor domain (EcDOS). Another objective was to describe inter-protein signal transduction in the two component signaling system AfGcHK-RR and structurally characterize these two interacting partners. Emphasis was also placed on the study of the interaction between model sensor domains and different signaling molecules and also on function of individual amino acids involved in the binding of these...
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Study of interactions between the FOXO3-DNA binding domain and small-molecular compounds
Dolejš, Vojtěch ; Obšilová, Veronika (advisor) ; Martínková, Markéta (referee)
This diploma thesis is part of a project aiming for the development of low molecular compounds which would be capable to inhibit the interaction between human transcription factor FOXO3 and DNA. Main goal of this thesis is the characterization of the interaction between the low molecular inhibitor S9 and the DNA-binding domain of FOXO3 protein (FOXO3-DBD) by using variety of biophysical methods such as NMR, microscale thermophoresis and native electrophoresis. FOXO transcription factors are important and evolutionary conserved regulatory proteins, which are involved in many crucial cellular processes. The activity of FOXO proteins is regulated by posttranslational modifications, out of which the most important are phosphorylation, acetylation and ubiquitination. Forkhead transcription factors participate in a variety of different cellular functions and are part of several signaling pathways. Its expression might be tissue specific. They contain approximately 100 amino acids long DNA- binding domain composed of several parts. Among its main functions belong the regulation of cell cycle and apoptosis, proliferation and cell differentiation, metabolism control and stress- response regulation. Tumor cells of lymfoblastome have developed resistance against chemotherapy by increasing activity of FOXO3...
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The study of properties of anticancer drugs ellipticine, etoposide and doxorubicin in the forms of nanocarriers
Lengálová, Alžběta ; Stiborová, Marie (advisor) ; Martínková, Markéta (referee)
Currently available anticancer therapies are inadequate and spur demand for improved technologies. Among others, the utilization of nanocarriers for anticancer drug delivery has shown great potential in cancer treatment. Nanocarriers can improve the therapeutic efficiency of the drugs with minimization of the undesirable side effects. To evaluate potential application of this technology, two forms of nanocarriers have been studied: multi-walled carbon nanotubes (MWCNTs) and apoferritin. The aim of this study was to determine, whether given cytostatics (ellipticine, etoposide and doxorubicin) are bound to these nanotransporters and how are they released from them, especially depending on pH. Since the pH of the tumor cells is lower than the pH of healthy cells it would be preferred that the drugs would release from nanocarriers at the lower pH while at the physiological pH the release of the drug would be eliminated. The results found show that ellipticine is actually released from its MWCNT- and apoferrtin-encapsulated form at acidic pH (5.0), while at pH 7.4 its interaction with nanocarriers is stable. Ellipticine released from MWCNT is activated by microsomal enzymes to reactive metabolites (13- hydroxyellipticine and 12-hydroxyellipticine) forming DNA adducts. The results indicate that both...
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Effect of sodium sulfide on the propreties of model globine-coupled heme-containing sensor proteins
Bartošová, Martina ; Martínková, Markéta (advisor) ; Man, Petr (referee)
Hydrogen sulfide mediates various physiological functions and along with carbon monoxide and nitric oxide it is an important gaseous signaling molecule. Cellular targets for H2S are proteins, enzymes, transcriptional factors or ion channels. In many cases, the effect of H2S on the regulatory protein is mediated by modifications of its cystein residues. In hemeproteins, the regulation of catalytic activity is induced by formation of the Fe(III)-SH complex or by reduction of the heme iron with subsequent formation of Fe(II)-O2 complex. The effect of Na2S on model sensor heme-containing proteins is presented in this thesis. Protein, isolated from bacterium Anaeromyxobacter sp. strain FW109-5, containing a globine coupled sensor domain and a histidine kinase domain is one of the studied proteins, the second one is protein isolated from bacterium Escherichie coli, containing a globine coupled sensor domain and a diguanylate cyclase domain. The effect of Na2S on both model proteins and their mutants was studied by UV-Vis spectral analysis. Spectra of YddV-HD Y43A were very unique, because thery confirmed formation of a homogenous complex Fe(III)-SH in this protein, whereas only mixtures of varous heme complexes were detected in other tested proteins. Additionally the effect of Na2S on functional domain...
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Study of adsorption efficiency of diosmectite and charcoal on selected model compounds causing acute intoxication in the Czech Republic
Mináriková, Michaela ; Martínková, Markéta (advisor) ; Sedláček, Jan (referee)
The first step in treatment of acute intoxications is usually based on a method suitable to eliminate the toxic agent from the poisoned body. The principle of such a method consists of binding the harmful substances to the surface of a suitable adsorbent material. The aim of the present study was to compare the adsorption ability of two adsorbent materials, namely diosmectite and activated charcoal towards selected model compounds which are most commonly involved in acute intoxication in the Czech Republic. The eleven model compounds were selected: acetylsalicylic acid, α-amanitin, amlodipine, digoxin, phenobarbital, ibuprofen, imipramine, carbamazepine, oxazepam, promethazine, and theophylline. Of the tested compounds, promethazine was most effectively adsorbed to diosmectite. Its adsorption to diosmectite (0.191 ± 0.035 mg promethazine/mg diosmectite) was significantly higher than its adsorption to activated charcoal. Amlodipine, imipramine and carbamazepine were adsorbed both to diosmectite and to charcoal, by analogous efficiencies. The effect of temperature and pH on the adsorption efficiencies of these adsorbents was also evaluated. The utilized pH simulated physiological conditions in the various parts of the gastrointestinal tract. Surprisingly, the pH was not found to significantly...
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The kinetic analysis of the enzyme reaction catalyzed by the globine coupled histidine kinase
Fojtíková, Veronika ; Martínková, Markéta (advisor) ; Vaněk, Ondřej (referee)
Two-component signal systems serve as basic stimulus-response coupling mechanism to allow organisms (predominantly bacteria) to sense and respond to changes in many environmental conditions. The prototypical system consists of two proteins, namely a histidine kinase, containing a sensor domain and catalytic kinase core, and a response regulator protein (RR protein). Extracellular stimuli are sensed by a histidine kinase sensor domain. Then ATP is bound to the catalytic kinase core and the γ-phosphoryl group is transferred to the conserved histidine residue. This phosphoryl group is subsequently transferred to a conserved aspartate residue within the RR protein. Phosphotransfer to the RR protein results in activation of a downstream effector domain that elicits the specific response (usually it is transcription activity, but a few RR proteins function as enzymes). The histidine kinase sensor domain is designed for specific ligand interactions. This master thesis focused on the unique histidine kinase containing a sensor domain with a globine structure, which coordinates a heme molecule, namely globin-coupled histidine kinase from Anaeromyxobacter sp. Fw 109-5 (AfGcHK) and its appropriate RR protein. The aim of this thesis was to study and characterize the phosphorylation activity of AfGcHK and RR...
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Production of recombinant cathepsin C from human blood fluke
Illichová, Hana ; Konvalinka, Jan (advisor) ; Martínková, Markéta (referee)
Blood flukes of the genus Schistosoma cause schistosomiasis, a serious parasitic disease occurring in tropical and subtropical areas. Cathepsin C (EC 3.4.14.1) is a digestive enzyme of the blood flukes which participates in the degradation of hemoglobin through its dipeptidyl aminopeptidase activity. This enzyme is critical for metabolism of the parasite and represents a potential target for the development of antischistosomal drugs. Cathepsin C has not yet been studied in detail. This bachelor thesis is focused on the development of expression systems for production of recombinant cathepsin C of Schistosoma mansoni (SmCC). The yeast Pichia pastoris system was used for the expression of an inactive SmCC precursor (zymogen) whose proteolytic stability was analysed. Furthermore, the expression system for SmCC in the protozoan Leishmania tarentolae was employed, and four different SmCC constructs were prepared to optimize production.
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