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Salts of 2-aminoethanol and ferrocene-based acids
Zábranský, Martin ; Štěpnička, Petr (advisor) ; Němec, Ivan (referee)
Combination of the compact but sterically flexible ferrocene scaffold with intermolecular binding potential and conformational variability of (2-hydroxyethyl)ammonium structural motif was utilised in the construction of solid crystalline materials. Crystallisation in systems containing ferrocenecarboxylic, 2-ferrocenylacetic, 3-ferrocenylpropionic, 3-ferrocenyl- acrylic, 3-ferrocenylacrylic, 3-ferrocenylpropiolic, ferrocene-1,1'-dicarboxylic or ferrocene- sulfonic acid with 2-aminoethanol afforded crystals of the corresponding salts. The resulting crystalline products were characterised with the usual methods (proton nuclear magnetic resonance, infrared spectroscopy, elemental analysis) and their crystal structures were determined by means of single-crystal X-ray diffraction analysis. The crystal structures of the salts mentioned above usually contain rather complicated two dimensional networks of charge-assisted hydrogen bonds. With the aim of studying potentially more simple hydrogen-bonded structures, additional crystallisation experiments were conducted in systems of ferrocenecarboxylic acid and 2-(methylamino)ethanol or 2-(dimethylamino)ethanol. These experiments yielded simple salt of the former amine and adducts of salts of both bases with ferrocenecarboxylic acid in the ratio of 1:1. The...
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Structural and functional analysis of cathepsin B1 from the blood fluke, Schistosoma mansoni
Jílková, Adéla ; Mareš, Michael (advisor) ; Obšil, Tomáš (referee) ; Mikeš, Libor (referee)
Schistosomiasis is a serious infectious disease that afflicts over 200 million people in tropical and subtropical regions. It is caused by Schistosoma blood flukes that live in human blood vessels and obtain nutrients from host hemoglobin, which is degraded by digestive proteases. Current therapy relies on a single drug and concern over resistance necessitates new drug development. In Schistosoma mansoni, cathepsin B1 (SmCB1) is a critical digestive protease that is a target molecule for therapeutic interventions. This thesis provides a comprehensive characterization of SmCB1 focused on structure-activity relationships and inhibitory regulation based on six crystal structures solved for SmCB1 molecular forms and complexes. SmCB1 is biosynthesized as an inactive zymogen in which the N-terminal propeptide operates as a natural intra-molecular inhibitor by blocking the active site. Detailed biochemical and structural analyses have identified a new and, so far, unique mechanism of SmCB1 zymogen activation through which the propeptide is proteolytically removed and the regulatory role of glycosaminoglycans in this process has been described. A study of SmCB1 proteolytic activity has revealed that the enzyme acts in two modes, as endopeptidase and exopeptidase, which makes it an efficient tool for host...
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Structure and magnetic properties of f-electron compounds and their hydrides
Mašková, Silvie ; Havela, Ladislav (advisor) ; Kamarád, Jiří (referee) ; Reiffers, Marián (referee)
Title: Structure and magnetic properties of f-electron compounds and their hydrides Author: Silvie Mašková Department: Deparment of Condensed Matter Physics Supervisor: Doc. RNDr. Ladislav Havela, CSc., Deparment of Condensed Matter Physics, Faculty of Mathematics and Physics, Charles University, Prague, The Czech Republic Abstract: Magnetic properties were studied in several types of actinide- and lanthanide-based ternary compounds. We have shown indirect that anisotropy of compressibility and thermal expansion can be related to the direction of magnetic moments at U-compounds with "soft" directions (where the closest U-U links are) perpendicular to the moments direction. Comparison of U and RE compounds of the 2-2-1 type indicates that contrary to U compounds, RE compounds can absorb much more hydrogen. The involvement of the f-states in metallic bond, which takes place at actinides and not in lanthanides, makes the U-based compounds apparently more stable against hydrogenation. Basic electronic properties were established for ζ -Pu19Os, which is a close analogy to β-Pu, and for its low-temperature variety η -Pu19Os. The results confirm that the volume is not the main parameter driving Pu properties, as β-Pu with intermediate volume is the most strongly correlated Pu phase. Keywords: uranium compounds,...
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Variations of actinide magnetism in uranium-base hydrides and other selected systems
Adamska, Anna Maria ; Havela, Ladislav (advisor) ; Arnold, Zdeněk (referee) ; Figiel, Henryk (referee)
Title: Variations of actinide magnetism in uranium-base hydrides and other selected systems. Author: Anna Maria Adamska Department / Institute: Department of Condensed Matter Physics Supervisor of the doctoral thesis: Doc. RNDr. Ladislav Havela, CSc., the Department of Condensed Matter Physics Faculty of Mathematics and Physics Charles University, Prague, Czech Republic and Assoc. Prof. Dr. hab. Nhu-Tarnawska Hoa Kim Ngan, Institute of Physics, Pedagogical University, Kraków, Poland. Abstract: Actinide magnetism was studied in three different types of systems. Variations of magnetic properties of UTGe hydrides as a function of hydrogen concentration prove that doping of U intermetallics by interstitial hydrogen leads to stronger magnetic properties, primarily caused by an increase of the inter-uranium separation. Sputter-deposited UFe2+x films, which are derived from the UFe2 Laves phase but have an amorphous structure, exhibit an increase of the Curie temperarture (to more than 400 K) with the Fe excess, which could not be achieved in the bulk. This is understood as a result of the prominent role of the 3d magnetism of Fe. Notoriously weakly magnetic plutonium was studied in the form of the alloy in the ζ-phase, which exists between 35 and 70 % U in Pu. Its susceptibility increases in a comparison to pure...
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The secreted aspartic proteases of Candida parapsilosis.
Marečková, Lucie ; Dostál, Jiří (advisor) ; Novotný, Marian (referee)
Candida parapsilosis is an opportunistic fungal pathogen of humans causing a variety of infections. Immunocompromised individuals represent the most threatened group of patients. The increasing frequency of infections and occurrence of drug resistant strains are the main reasons for research focused on novel antimycotic compounds. Inhibition of secreted aspartic proteases (Sap) of pathogenic Candida spp. appears to be a potential target of therapeutic intervention. The genome of C. parapsilosis contains at least three genes coding for secreted aspartic proteases, denominated SAPP1-3. Protease Sapp1p has been well biochemically and structurally characterized, whereas Sapp2p and Sapp3p have been given less attention. The first part of the thesis is focused on structural analysis of Sapp1p complexes with selected peptidomimetic inhibitors binding to the active site of the enzyme. In addition, complex of the isoenzyme Sapp2p with the well-known secreted aspartate inhibitor Pepstatin A has been analyzed. The second part is related to the fact that C. parapsilosis belongs to the Candida spp. with the unique ability to translate standard leucine CUG codon mostly as serine. Even though it is a non-conservative substitution of hydrophobic amino acids for a hydrophilic one, this unique ability is maintained for more...
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Crystal structure of inorganic phosphates
Fejfarová, Karla ; Mička, Zdeněk (advisor) ; Žák, Zdirad (referee) ; Sýkora, Jan (referee)
½ž ËÙÑÑ ÖÝ Ó ×× ÖØ Ø ÓÒ ½ž½ž Ñ Ó ×× ÖØ Ø ÓÒ The aim of this thesis was to solve and describe the crystal struc- ture of selected inorganic phosphates. Nine different compounds have been studied, including the NASICON type phosphates Co0.5Ti2(PO4)3, Mn0.5Ti2(PO4)3, Na3.215Fe2(PO4)3, the iron(II) diphosphate Fe2P2O7 and hydrates of rare-earth hydrogen diphosphates LnHP2O7·3H2O (Ln = Y, Tb, Dy, Yb) and TbHP2O7·4H2O. While NASICON type phos- phates and rare-earth hydrogen diphosphates have a conventional three- dimensional crystal structure, the structure of α-Fe2P2O7 is incommen- surately modulated and has been described in (3+1)-dimensional super- space. ½ž¾ž ÇÚ ÖÚ Û Ó Ø ÓÒØ ÒØ Ó ×× ÖØ Ø ÓÒ Dissertation is divided in six parts. Part 1 introduce the crystal struc- ture analysis, the concept of aperiodic crystals and the superspace ap- proach. Part 2 describes course of X-ray diffraction experiment and used experimental equipment. The next three parts, Part 3, Part 4 and Part 5, in which the structures of NASICON-type phospates, iron(II) diphos- phate, and rare-earth hydrogen diphosphates are discussed, are the main parts of this work. Part 1. Introduction and Initiation Chapter 2, "Basic principles of crystal structure analysis" con- cerns by fundamentals of crystal structure analysis, i.e. behaviour of X-...
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Growth of metastable fcc Fe thin films on Cu/Si(100) substrates
Horký, Michal ; Cháb, Vladimír (referee) ; Urbánek, Michal (advisor)
This diploma thesis deals with the preparation of epitaxially grown metastable paramagnetic Fe films alloyed by Ni on Cu/Si(100) substrates at RT. Molecular beam epitaxy of Cu(100) buffer layer was performed on H-Si(100) native SiO2 free samples treated by etching in HF or thermal treatment. The epitaxially grown Cu layers with thickness ranging from 50 up to 130 nm serves as suitable substrate for the deposition of 44-ML-thick paramagnetic Fe78Ni22. The film growth was taking place in CO atmosphere and as well as Ni it led to paramagnetic film stabilization. The structural and magnetic ion-beam-induced transformation of desired Fe-Ni structure was performed and propeties of irradiated films were characterized afterwards by MOKE. Then some specific patterns on Si(100) by e-beam litography were fabricated and they served as suitable matrix for Cu(100) buffer layer and paramagnetic Fe. Prepared Si(100), globally and locally deposited metal films were examined by LEED, XPS, AFM, AES, SEM a STM. The recorded results showed the possibility of paramagnetic films preparation on H-Si(100) where it was possible to make ferromagnetic patterns on paramagnetic background by irradiation of specific ion dose.
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Study of organic molecular compound by x-ray radiation
Stejkora, Jakub ; Richtera, Lukáš (referee) ; Salyk, Ota (advisor)
Derivates of diketopyrrolopyrrole are coloured pigments with potential use in field of organic semiconductor structures. Their electrical attributes such as conductivity, photocon- ductivity and electroluminescence relate to their crystal structures, that determine charge transport path through the compound. The work deals with determination of these structures by using x-ray diffractometry. The diffractogram based on known crystalografic structure of diketo-dipyridyl-pyrrolo-pyrrole is modeled by available software and measured diffractogram is used for structure re-modeling. This method is used for other related derivates with unknown crystal structure.
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Surface crystallinity at the sight of electrons
Frank, Luděk ; Mikmeková, Šárka ; Mika, Filip ; Müllerová, Ilona
Scattering of electrons, injected into solids in order to produce an electron optical image of their surfaces, is governed by inner potentional of the sample with its spatial distribution inherent to the target structure. Except truly amorphous materials of the spatial arrangement range shorter than the interaction volume of electrons, we meet anisotropic scattering with the resulting image signal responding to the local crystalline structure. Incident electrons undergo scattering events the number of wich depends on their energy and on the scattering cross section of the material and the final emitted current results from statistics of these events.
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Structural basis of HIV-1 and HIV-2 protease inhibition bya monoclonal antibody
Řezáčová, Pavlína ; Lescar, J. ; Brynda, Jiří ; Fábry, Milan ; Bentley, G. A. ; Sedláček, Juraj
The murine monoclonal antibody 1696, produced by immunisation with the HIV-1 protease,inhibits the catalytic activity of the enzyme of both the HIV-1 and HIV-2 isolates, with inhibitionconstants in the low nanomolar range. This antibody cross-reacts with peptides that include theN-terminus of the enzyme (residues 1-7), a region which is highly conserved in sequence amongdifferent viral strains and which, furthermore, is crucial for homodimerization to the activeenzymatic form.<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />We report here two crystal structures of a recombinant single-chain Fv fragment of mAb 1696,expressed in E. coli, as a complex with a cross-reactive peptides from the HIV-1 PR and theHIV-2 PR at 2.7 ? resolution and 1.9 ? resolution respectively. On the basis of the interactionsseen in the complex three-dimensional structures, the cross-reactivity between mAb 1696 withthe HIV-1 and HIV-2 protease and their N-terminal peptides can be explained. In addition, acandidate mechanism of HIV PR inhibition by mAb 1696 is proposed which may help thedesign of alternative HIV protease inhibitors, aimed at dissociating the homodimeric viral enzyme.
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