National Repository of Grey Literature 38 records found  beginprevious28 - 37next  jump to record: Search took 0.00 seconds. 
Interaction preferences in protein - DNA complexes
Jakubec, Dávid ; Vondrášek, Jiří (advisor) ; Berka, Karel (referee)
Interaction preferences in protein - DNA complexes Dávid Jakubec Abstract Interactions of proteins with DNA lie at the basis of many fundamental bio- logical processes. Despite ongoing efforts, the rules governing the recognition of specific nucleic acid sequences have still not been universally elucidated. In this work, I attempt to explore the recognition process by splitting the intricate network of contacts at the protein - DNA interface into contribu- tions of individual amino acid - nucleotide pairs. These pairs are extracted from existing high-resolution structures of protein - DNA complexes and in- vestigated by bioinformatics and computational-chemistry based methods. Criteria of specificity based on the coupling of observed geometrical prefer- ences and the respective interaction energies are introduced. The application of these criteria is used to expand the library of amino acid - nucleotide pairs potentially significant for direct sequence recognition. Electrostatic poten- tial maps are calculated for individual nucleotides as well as for selected complexes to investigate the physical basis of the observed specificity. 1
Intermolecular interactions in proteins
Kysilka, Jiří ; Vondrášek, Jiří (advisor) ; Ettrich, Rüdiger (referee) ; Banáš, Pavel (referee)
Intermolecular Interactions in Proteins - Abstract Mgr. Jiří Kysilka Non-covalent interactions are responsible for the protein folding and the molecular recognition during the protein interaction with other molecules, including various ligands, other proteins and solvent molecules. In order to understand these processes, exhibited by protein molecules, a proper description of non-covalent interactions is needful. Most methods that are computationally available for the systems of biological interest have difficulties handling with the dispersion term. In this thesis, a density functional theory / coupled clusters (DFT/CC) correction scheme is utilized for a set of small molecules, interacting with a graphitic surface. The results serve as a benchmark for the interaction of the functional groups of proteins with hydrophobic environment. In the following part of this thesis, the role of non-covalent interactions in proteins was studied for the processes of protein-protein interaction and protein hydration. Interaction interfaces has been localized in a set of 69 protein dimers and their composition has been characterized. Interfaces has been shown to prefer branched-chain hydrophobic amino acids (Ile, Leu, Val), aromatic amino acids (Phe, Tyr) and exclude the charged amino acids except of Arg. It was...
Identification and modeling of gene expression regulatory networks during streptomycetes germination
Straková, Eva ; Vohradský, Jiří (advisor) ; Stopka, Pavel (referee) ; Vondrášek, Jiří (referee)
Streptomycetes have been studied mostly as producers of antibiotics and for fundamentals of complex bacterial cell development. Here, transcriptomic and proteomic approaches were applied to systems study of Streptomyces coelicolor germination as a developmental transition from dormancy to the vegetative stage. The time dynamics of the gene expression levels represented by mRNA and intracellular protein accumulation and synthesis were measured throughout 5.5 h of germination at 13 time points by employing both DNA microarray and two-dimensional gel electrophoresis techniques. Using a numerical model of gene expression, genetic networks were reconstructed and functional groups of genes controlled by the sigma factors were identified. Modeling of the regulatory interactions provided a set of parameters allowing simulate kinetics of gene expression control among the sigma factors and their target genes. Particularly regulons of two sigma factors, SigR and HrdD, were identified. The analysis assigned their key role during the germination process. Analysis of global trends in the gene/protein expression revealed that the full capability of regulatory mechanisms responding to the environmental cues is reached within the first hour of germination, and identified the basic gene/protein functional groups...
Molecular modelling in drug development
Kolář, Michal ; Hobza, Pavel (advisor) ; Vondrášek, Jiří (referee) ; Clark, Tim (referee)
Molecular modelling has become a well-established tool for studying biological mole- cules, moreover with the prospect of being useful for drug development. The thesis summarises research on the methodological advances in the treatment of molecular flexibility and intermolecular interactions. Altogether, seven original publications are accompanied by a text which aims to provide a general introduction to the topic as well as to emphasise some consequences of the computer-aided drug design. The molecular flexibility is tackled by a study of a drug-DNA interaction and also by an investigation of small drug molecules in the context of implicit solvent models. The approaches which neglect the conformational freedom are probed and compared with experiment in order to suggest later, how to cope with such a freedom if in- evitable. The noncovalent interactions involving halogen atoms and their importance for drug development are briefly introduced. Finally, a model for a faithful description of halogen bonds in the framework of molecular mechanics is developed and its per- formance and limits are tested by a comparison with benchmark ab initio calculations and experimental data. 1
Intramolecular and intermolecular interactions in proteins
Fačkovec, Boris ; Vondrášek, Jiří (advisor) ; Berka, Karel (referee)
Folding free energy of a protein is a delicate balance between stabilizing and destabilizing non-covalent itneractions. In this work, we decompose folding free energy into physically meaningful contributions, in which we aim to find general trends. Empirical potential is used to calculate interaction energy between all protein fragments, which are classified based on their dominant term in multipolar expansion. Calculations are done using 1200 non-redundant structures from PDB database. Based on the general trends found in interactions between these fragments, we attempt to better understand relationships between interaction energies calculated using computational chemistry methods and their corresponding free energy contributions on stabilization. 1
Interaction of proteins with inhibitors: quantum chemical study
Dobeš, Petr ; Hobza, Pavel (advisor) ; Vondrášek, Jiří (referee) ; Jurečka, Petr (referee)
This dissertation focuses on theoretical studies of the interaction between protein kinases and their inhibitors. Studied protein kinases, cyclin-dependent kinase 2 (CDK2) and CK2 kinase (casein kinase 2) play an important role in regulating cellular processes in eukaryotic organisms. Their abnormal function in human cells can lead to serious diseases. This process can be stopped by blocking the aberrant protein kinases using specific low molecular weight inhibitors. Inhibitors of protein kinases typically bind to the active site of the enzyme by noncovalent interactions. Theoretical description of these interactions using quantum-chemical and molecular mechanical methods can help in understanding the biophysical principles governing the binding. These, in turn, can be subsequently used for a rational drug design of more effective and more specific inhibitors. The stabilization energy of the complex of CDK2 with inhibitor roscovitine is predominantly formed by the dispersion energy. DFT methods, which do not describe the dispersion energy was thus completely inappropriate for the treatment of such a system. When an empirical term is included to correct for the description of dispersion, such methods, as e.g. the SCC-DFTB-D, can be recommended for computation of this or similar complexes. The dominant part...
Noncovalent Interactions in the Gas Phase and Aqueous Solution: Theoretical Study
Zendlová, Lucie ; Hobza, Pavel (advisor) ; Burda, Jaroslav (referee) ; Vondrášek, Jiří (referee) ; Jurečka, Petr (referee)
EAPUr rr|lclltal \ alLlť5' 5 Conclusions :, , . In the ia) part of present work we c intera cti on b etween u d"',il ". . . thy;';; il:'::: :íJTj.:lÍ' lI jl.#.ffiJ,lil itt8:"é'siia small number or*u.",7nJ organió solvent ňr"."i", (CH3.H, solvents yů[T"i^f.completely different interactions between the bases and the b"''" p.'"{ ;' "idilnn il#} il-t ÍT:!fl,-. i: : " o:] Y" .'h:.-S,t.* tu,", ot tt," moleóule Iuórc 'u'r' u property, and the'. .'l,'..,ťff,.'*lt'Lť':.lill:ilF.S'T!,l;situated above or belolthe !Á; ;;i. ;';;lě'"o ri," olašó ň"l"-.\,," ,, unique y"J::fiffii:x::. ."n'o*ison with otr,!. .otu"nt,, uň.'r,"í'ř;;.". are the In the ib) part_of present work based on the MD, SCC_DDFTB_D and ;"",'.Y|Tť'.#1.:."ffi i"T."lrJ'".r""u.'".XincorporateJ."-oŇTduplexwe i) Replacing nucleic acid base by modified nucleobase X leads.*:'] ,o Structural changes of the centrď -uuš"-pui. Gtu.tarrangement of central modified base pairs). ónli with ttresma'lest modified nucleobase p 'r'" Á.iJ.;;*;;.í' (A-P, P-T) stay planar. In the case 'of.B-T, Á-il.;';6 in specificorientation, one of the modified nuú"JÁ""x"*íto.""a outfrom DNA duplex. ii) Incre, .,""olr'iT"i1iTi1fi" or modified nucleobase X increases rhe iii) The highest s.ďectivity among- all base ana|ogue studied wasfound for modified nu"l"obus" O In the secono pu* of...
Interaction of heteroboranes with biomolecules: Accurate quantum chemical study
Fanfrlík, Jindřich ; Hobza, Pavel (advisor) ; Fišer, Jiří (referee) ; Otyepka, Michal (referee) ; Vondrášek, Jiří (referee)
Charles University in Prague Faculty of Science Department of Physical and Macromolecular Chemistry Interaction of heteroboranes with biomolecules: Accurate quantum chemical study Doctoral Thesis Abstract RNDr. Jindřich Fanfrlík Advisor: Prof. Ing. Pavel Hobza, DrSc. Institute of Organic Chemistry and Biochemistry, AS CR Center for Biomolecules and Complex Molecular Systems Prague 2008 Univerzita Karlova v Praze Přírodovĕdecká Fakulta Katedra fyzikální a makromolekulární chemie Interakce heteroboranů s biomolekulami: kvantovĕ chemická studie Autoreferát disertační práce RNDr. Jindřich Fanfrlík Školitel: Prof. Ing. Pavel Hobza, DrSc. Ústav organické chemie and biochemie, AV ČR Centrum biomolekul a komplexních molekulových systémů Praha 2008 Introduction The world wide epidemic of AIDS is caused by two species of the human immunodeficiency virus (HIV-1 and HIV-2). Its 9200-bases-long RNA genome contains three main genes: gag, pol and env. The enzymes located within the pol gene (protease PR and reverse transcriptase RT) have become major targets for drug discovery, e.g. RT inhibitor Tenofovir disoproxil fumarate (DF) discovered by A. Holy at UOCHB in Prague and manufactured by Gilead Sciences and also already ten HIV-1 PR inhibitors (PIs) have been approved for use in the clinics: The evolution of drug...

National Repository of Grey Literature : 38 records found   beginprevious28 - 37next  jump to record:
See also: similar author names
1 Vondrášek, Jakub
1 Vondrášek, Jan
1 Vondrášek, Jiří Bc.
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