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ALAS2 gene sequencing
HOLOUBKOVÁ, Renata
In my bachelor thesis I dealt with the detection of mutations in the ALAS2. In the theoretical part, I dealt with the introduction to genetic concepts and the field of genetics itself. The work begins from the cell itself, to the chromosomes, through mutations. I also dealt directly with the ALAS2 gene. In the following chapters, I focused on heme, because the ALAS2 gene encodes an enzyme that is responsible for heme production. Last but not least, I have described the disease erythropoietic protoporphyria and sideroblastic anemia, which arise precisely due to mutations in this gene. In the practical part, I examined the ALAS2 gene of exon 11. I examined 25 anonymized samples, from which I isolated DNA. I then amplified the desired section of the gene by PCR. I prepared the samples for the sequencing method, which took place at GenSeq s.r.o. In the last part of my bachelor's thesis, I dealt with the evaluation of sequences and processing of results, but also with the evaluation of sequences from children from Karviná and České Budějovice, which I received. No mutations were found from the whole examined group and the group to be evaluated. For evaluation from a larger data set, the results of the mutations found in the research were added.
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Light-harvesting like domain of the cyanobacterial ferrochelatase
PAZDERNÍK, Marek
This thesis is focused on elucidating the function of the C-terminal transmembrane lightharvesting complex like (LHC) domain of the cyanobacterial ferrochelatase (FeCh). Using the model cyanobacterium Synechocystis PCC 6803, I show that the FeCh LHC domain can bind chlorophyll (Chl) and carotenoids; however, this pigment binding occurs only when the biosynthesis of heme and Chl in the cell is misbalanced. Further, I found that point mutation, which prevents the pigment binding to FeCh LHC domain results in a misregulated ratio between heme and Chl during stress conditions due to low heme accumulation. My data also show that the FeCh LHC domain interacts with CurT protein most likely to localize the FeCh into a specialized membrane domain, where the synthesis of photosystem II is proposed to occur. Based on my data I propose that the role of the FeCh LHC domain is to monitor the availability of Chl during photosystem biogenesis and to coordinate Chl availability with the synthesis of heme.
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Specific heme interaction modulates the conformational dynamics and function of p53
Sergunin, Artur ; Martínková, Markéta (advisor) ; Dračínská, Helena (referee)
Tumor suppressor p53 is one of the most studied proteins in terms of cancer and the mechanism of its formation. The general function of p53 is based on the transcriptional regulation of various genes, which can differently influence numerous cellular processes. Recent studies revealed a relationship between p53 and iron homeostasis within the cell. In particular, p53 was shown to interact with a molecule of heme, and this interaction ultimately disrupts the DNA-binding ability of p53 and promotes its proteasomal degra- dation. This work focuses on a detailed description of heme binding to the p53. For this purpose, we isolated two forms of p53, heme-free and heme-bound. We discovered that conformational dynamics of heme-free and heme-bound p53 differ, with the latter exhibi- ting a higher degree of flexibility. We also confirmed previous reports that heme indeed interacts with a cysteine residue in a specific manner. However, heme binding does not disrupt the oligomeric state of p53 or its native zinc binding ability. Finally, we showed that heme-bound p53 exhibits severely impaired DNA-binding ability as opposed to the heme-free form. Keywords: heme, sensor proteins, p53 protein, transcription factor, intrinsically disor- dered proteins
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The role of iron in the metabolism of the amoeba Naegleria gruberi
Ženíšková, Kateřina ; Konvalinka, Jan (advisor) ; Hlouchová, Klára (referee)
Iron is a biogenic trace element that is vital for all organisms on the planet Earth. This element occurs in biological systems in the form of Fe3+ and Fe2+. These two forms are often incorporated in heme structures or iron-sulfur clusters. Proteins containing iron ions have a wide range of functions in organisms. The main functions include the transport of electrons in the respiratory chain (Rieske's proteins, cytochromes), DNA synthesis (ribonucleotide reductase) and the participation in the Krebs' cycle (aconitase, succinate dehydrogenase). Naegleria gruberi is a nonpathogenic amoeba known for its pathogenic relative Naegleria fowleri. This organism causes the primary amoebic meningoencephalitis. An interesting fact about Naegleria gruberi genome is that it contains genes for both aerobic and anaerobic metabolisms. The purpose of my bachelor work was to investigate the effect of availability of iron ions on metabolism in Naegleria gruberi. Changes in the activities of enzymes from different metabolic pathways were studied including lactate dehydrogenase, isocitrate dehydrogenase, Fe- hydrogenase, aconitase and fumarase. The most significant changes were observed in the activities of alcohol dehydrogenase and Fe-hydrogenase. Key words: Iron, heme, iron-sulfur clusters, availability of iron ions,...
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Preparation and preliminary characterization of the eukaryotic initiation factor 2α and its heme regulated kinase
Ovad, Tomáš ; Martínková, Markéta (advisor) ; Stráňava, Martin (referee)
Heme sensor proteins perform a variety of important functions in both prokaryotic and eukaryotic organisms. Heme-regulated inhibitor (HRI) is an example of a eukaryotic heme-sensor protein, which catalyzes the phosphorylation of the α subunit of the eukaryotic initiation factor 2 (eIF2α). In this bachelor thesis, the pET-21c(+)/eIF2α plasmid was amplified and its authenticity for the eIF2α expression was verified with the use of two independent methods. Next, HRI and eIF2α were produced using the recombinant expression in E. coli BL-21(DE3) cells transformed with the pET- 21c(+)/eIF2α and pET-21c(+)/HRI plasmid, respectively. Both proteins were then isolated from the cells and purified with the use of affinity chromatography and gel permeation chromatography. eIF2α was obtained in sufficient yield (560 μg out of 1 l of TB medium) and purity (90%). A lower yield (25 μg out of 1 l of TB medium) and purity (20%) was reached in the case of HRI. On the other hand, the authenticity of the HRI product was confirmed using spectrophotometric characterization and its enzyme activity was verified as well. Pilot experiments showed that GTP may replace ATP in the process of eIF2α phosphorylation, while UTP and CTP may not.
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Heme sensor proteins sensing both heme and CO
Andrlová, Dominika ; Martínková, Markéta (advisor) ; Libus, Jiří (referee)
Heme, a protoporhyrin IX iron complex, is an important component of many proteins necessary for oxygen transfer, storage and activation, as well as for electron transfer. Another group of hemoproteins includes heme sensor proteins. They are either capable of detecting heme itself, which can regulate in turn the sensor function (heme-responsive sensors) or heme forms a binding site for small gas molecules (O2, CO and NO) and the heme-based gas sensors are regulated by these diatomic gases. However, in the case of some proteins their classification is not clear showing a properties of both heme sensor proteins families. Their functions are regulated by heme interaction and a further change in their function after binding of a gas molecule to heme was observed. This summary search is focused on specific representatives of heme-responsive sensors (which function is regulated by heme binding), in which the further influence of the CO molecule on their functions have recently been observed. It is discussed whether some heme-responsive sensors are also heme-based CO sensors aiming the most recent findings about the selected specific heme sensors representatives. Key words: heme, heme sensor proteins, heme-based gas sensors, CO sensors, heme-responsive sensors, heme redox sensors
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Structure and function relationships of model hemoproteins
Lengálová, Alžběta ; Martínková, Markéta (advisor) ; Hudeček, Jiří (referee) ; Muchová, Lucie (referee)
Heme is one of the most important and most studied cofactors that are essential for proper function of many proteins. Heme-containing proteins comprise of a large group of biologically important molecules that are involved in many physiological processes. The presented dissertation is focused on two groups of heme sensor proteins, namely prokaryotic heme-based gas sensors and eukaryotic heme-responsive sensors. Heme-based gas sensors play an important role in regulation of many bacterial processes and consist usually of two domains, a sensor domain and a functional domain. The dissertation thesis aims at the study of two model bacterial heme-based gas sensors, histidine kinase AfGcHK and diguanylate cyclase YddV, in order to elucidate their mechanism of interdomain signal transduction. Using X-ray crystallography and hydrogen-deuterium exchange coupled to mass spectrometry approaches, significant differences in the structure of the AfGcHK protein between the active and inactive forms were described. The signal detection by the AfGcHK sensor domain affects the structural properties of the protein, and these conformational changes then have indirect impact on the enzyme activity of the functional domain. Further, the dissertation pays more attention to the effect of a sensor domain dimerization...
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Biochemical characterization of a model heme sensor protein
Tajovská, Eva ; Martínková, Markéta (advisor) ; Jeřábek, Petr (referee)
Hemoproteins play a lot of important roles within the living organism. One of these being the sensor function - heme sensor proteins are able to detect the changing concentration of heme in organisms. Heme itself serves as a signalling molecule for these proteins. Heme-based gas sensor proteins use a biatomic gas molecule as a signalling molecule. Signal transduction begins once the gas molecule is bound to the heme molecule which is already tightly bound in the protein sensing domain. Both these types of signalling regulate a number of physiological processes in the prokaryotic and eukaryotic organisms. The theoretical part of the bachelor thesis summarizes recent scientific studies on heme sensor proteins, while the experimental part focuses on the properties of a specific model sensor hemoprotein. A direct oxygen sensor from E. coli (EcDOS) was selected as a model protein. Furthermore, the thesis deals with a truncated form of the EcDOS protein, an isolated sensor domain with a PAS structure (EcDOS-PAS). The experimental part aimed at expressing and isolating of both mentioned proteins from E. coli BL-21 (DE3) cells. Finally, both the EcDOS and EcDOS-PAS proteins were preliminarily characterised and their properties compared. The yield of the EcDOS-PAS was several times higher than the yield of...
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