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Structure and interaction of human 14-3-3 regulatory protein using in vitro photoaffinity labelling in combination of protein nano-probes and mass spectrometry
Mazurová, Martina ; Šulc, Miroslav (advisor) ; Dračínská, Helena (referee)
This thesis is focused on the study of the structure and mechanism of human 14- 3-3 protein, which is one of the important regulatory proteins present in all eukaryotic cells. Nowadays it is known seven isoforms of this protein in mammals. Although their crystal structure shows a high similarity, their mutual comparison reveals some changes. The aim of this work is to prepare experimental tools for verification whether the differences in the crystal structure of the ζ isoform are present in solution and how the structure-functional mechanism of this isoform is affected. The otimization of 14-3- 3zeta recombinant protein expression with incorporated a photo-labile analog of leucine in the protein sequence was performed using limiting medium with prokaryotic expression system of E. coli BL-21 DE3 Gold or system of auxotrophic E. coli K-12 with non-functional leucine biosynthesis.
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Parasite cystatins as inhibitors of cysteine proteases: structural aspects of functional specificity and their evolution
Buša, Michal ; Mareš, Michael (advisor) ; Hudeček, Jiří (referee) ; Kukačka, Zdeněk (referee)
Members of the cystatin family are important inhibitors of cathepsin-type cysteine proteases and are involved in a number of pathologies. Parasite cystatins are attractive target molecules for parasite control, but our knowledge about them is still limited. This work is focused on cystatins of two blood-feeding parasites: the common tick (Ixodes ricinus) as the main vector of Lyme disease and tick-borne encephalitis, and the liver fluke (Fasciola hepatica), the causative agent of fasciolosis. Four novel cystatins were functionally and structurally characterized to determine the structural determinants of their inhibitory specificity and describe them in the context of evolution and physiological role of cystatins. The cystatin FhCyLS-2 from F. hepatica has broad inhibitory specificity and is suggested to play a dual role in the regulation of proteolytic systems in host tissue and the parasite gut. FhCyLS-2 combines the characteristics of two cystatin subfamilies in a unique way and is a model representative of a novel evolutionary group of cystatins identified in several orders of parasitic flukes. Ricistatin and iristatin are salivary cystatins of I. ricinus with immunomodulatory effects on the host caused by an exceptionally narrow inhibitory specificity. It was explained by structural modifications of...
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Engineering and selection of protein binders recognising medically important cytokines
Huličiak, Maroš
Protein engineering attracts more attention as a powerful tool of biotechnology and medicine. Small, engineered proteins derived from protein molecules of stable fold, the so called scaffolds, are potential replacements of supplements of more widely used antibodies. In this thesis, I introduce utilization of two scaffold molecules designed in our laboratory for development of stable and specific protein binders of high affinity. This thesis discusses the development of binders interacting with medically important human cytokines and their cellular receptors, interleukin-10, interleukin-28 receptor, and interleukin-9 receptor alpha. Recombinant cytokine and receptor proteins were expressed in eukaryotic cells in high yields and quality and served as molecular targets for selections using various display methods of directed evolution. We demonstrated that application of ribosome and yeast display methods or their unconventional combination in a newly developed integrated pipeline leads to successful generation of high affinity and specificity binders based on newly designed protein scaffolds called 57aBi and 57bBi.
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Engineering and selection of protein binders recognising medically important cytokines
Huličiak, Maroš ; Schneider, Bohdan (advisor) ; Pichová, Iva (referee) ; Kukačka, Zdeněk (referee)
Protein engineering attracts more attention as a powerful tool of biotechnology and medicine. Small, engineered proteins derived from protein molecules of stable fold, the so called scaffolds, are potential replacements of supplements of more widely used antibodies. In this thesis, I introduce utilization of two scaffold molecules designed in our laboratory for development of stable and specific protein binders of high affinity. This thesis discusses the development of binders interacting with medically important human cytokines and their cellular receptors, interleukin-10, interleukin-28 receptor, and interleukin-9 receptor alpha. Recombinant cytokine and receptor proteins were expressed in eukaryotic cells in high yields and quality and served as molecular targets for selections using various display methods of directed evolution. We demonstrated that application of ribosome and yeast display methods or their unconventional combination in a newly developed integrated pipeline leads to successful generation of high affinity and specificity binders based on newly designed protein scaffolds called 57aBi and 57bBi.
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Modulation of interactions of cytokines and their receptors
Kolářová, Lucie ; Schneider, Bohdan (advisor) ; Rozbeský, Daniel (referee) ; Osička, Radim (referee)
Protein-protein interactions and interactions with other molecules including DNA and RNA, play an important role in a range of biological activities and processes in all living cells. Understanding of protein-protein interactions, new approaches, and tools for their modulations are valuable for medicine, biotechnology, and drug development. We used the interleukin-10 family of cytokines as a model system for our research of biological interactions and modulation of their functions. A key prerequisite to study biological processes and a detailed understanding of biomolecular interactions is a recombinant protein that is stable under a broad range of conditions. Recombinant protein expression in sufficient yield and quality is often a challenging task. Therefore, we aimed at developing new approaches in protein design and production. In the first part of our study, we modified IL-24, a member of the IL-10 family to increase its expression and stability. We demonstrated that protein engineering is a powerful tool in research of difficult protein targets. In the second part of our study, we adopted new approaches in designing new protein scaffolds suitable for use in the ribosome and yeast display techniques. Protein scaffolds have become promising alternatives to antibodies in protein drug...
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Preparation of DNA-binding domain of Forkhead transcription factor FOXO3
Dolejš, Vojtěch ; Šulc, Miroslav (advisor) ; Ptáček, Jakub (referee)
This bachelor 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 preparation of 15 N-labelled DNA-binding domain of FOXO3 protein (FOXO3-DBD) and verification of its native structure using 1 H- 15 N HSQC NMR experiment. 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, although its expression is limited to specific tissues. 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. Some types of tumor cells have developed resistance against chemotherapy by increasing activity of FOXO3 transcription factors. For this reason, it is necessary to look for means to specifically suppress the function of this...
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Targeted modifications of the protein-protein interactions: Ternary complex of interferon-γ as a model system
Zahradník, Jiří ; Schneider, Bohdan (advisor) ; Obšilová, Veronika (referee) ; Vaněk, Ondřej (referee)
A key prerequisite for a deeper understanding of biological processes at molecular level is a detailed description of the three-dimensional structure of interaction partners and their complexes. We adopted the IFN-γ complex as our model system. Even though IFN-γ is one of the key modulators of the immunity response, which has been studied intensively for more than 60 years, the structure of the accessory receptor chain and the understanding of the IFN-γ complex is still lacking. In this work we firstly discussed the binary system between IFN-γ and its high affinity receptor R1 which is structurally known. Using a new innovative methodology we focused on the modulation of the affinity between IFN-γ and its receptor R1. Our approach was based on the modulation of protein - protein stability by mutating cavities in the proteins' structure and increasing the affinity about seven-fold. Secondly, we crystallized and solved the structure of the IFN-γ receptor 2, the accessory receptor molecule. Our analysis of variable residues on the surface of the structures of type II family receptors, to which receptor 2 belongs, revealed the putative binding site for IFN-γ. In the third part of our work, we crystallized IFN-γ from olive flounder Paralichthys olivaceus and solved its structure at 2.3 Å resolution (PDB...
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Identification of crystal packing contacts using a method for detection of protein-protein interaction sites
Mitková, Natália ; Hoksza, David (advisor) ; Jakubec, Dávid (referee)
One of the fundamental issues when obtaining the protein quaternary structures is to be able distinguish biological interfaces from crystal packing contacts. The existence of these false contacts is the consequence of the crystallographic method which is used for obtaining the tertiary and quaternary structure. Gaining knowledge of how proteins interact in 3D space is key to understanding their functions and offers the opportunity to apply the knowledge to inhibitor impact analysis, drug design, immunotherapy, or de novo protein design. Furthermore, this knowledge is an essential requirement when applying in silico approaches. The bachelor thesis is divided into two parts. The first part contains literature retrieval of existing methods addressing the problem of crystallographic contact detection together with relevant datasets for an objective evaluation. The second practical part is focused on the comparison of evaluations of the previously developed method for the protein-protein interface prediction, INSPiRE, and the EPPIC classifier. Key words: bioinformatics, crystal packing contact, crystallography, protein structure, protein- protein interactions
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Targeted modifications of the protein-protein interactions: Ternary complex of interferon-γ as a model system
Zahradník, Jiří
A key prerequisite for a deeper understanding of biological processes at molecular level is a detailed description of the three-dimensional structure of interaction partners and their complexes. We adopted the IFN-γ complex as our model system. Even though IFN-γ is one of the key modulators of the immunity response, which has been studied intensively for more than 60 years, the structure of the accessory receptor chain and the understanding of the IFN-γ complex is still lacking. In this work we firstly discussed the binary system between IFN-γ and its high affinity receptor R1 which is structurally known. Using a new innovative methodology we focused on the modulation of the affinity between IFN-γ and its receptor R1. Our approach was based on the modulation of protein - protein stability by mutating cavities in the proteins' structure and increasing the affinity about seven-fold. Secondly, we crystallized and solved the structure of the IFN-γ receptor 2, the accessory receptor molecule. Our analysis of variable residues on the surface of the structures of type II family receptors, to which receptor 2 belongs, revealed the putative binding site for IFN-γ. In the third part of our work, we crystallized IFN-γ from olive flounder Paralichthys olivaceus and solved its structure at 2.3 Å resolution (PDB...
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Protease Inhibitors as a Research Tool: Design, Synthesis and Evaluation of HIV PR and GCPII Inhibitors
Schimer, Jiří
This dissertation thesis focuses on creating tools for the analysis and potential therapeutic intervention in the biological processes regulated by proteolysis. I focus on two important proteolytic enzymes: HIV-1 protease, which is indispensable for the polyprotein processing of the nascent virus and thus for the development of infectious viral particle, and glutamate carboxypeptidase II, a tumor marker and a neuropeptidase from the prostate and central nervous system. Rational design of inhibitors of these therapeutically relevant enzymes serves two purposes: firstly, protease inhibitors were shown to be powerful drugs (HIV protease is in fact the example of successful drug development driven by structural biology). Secondly, and in the context of this thesis perhaps more importantly, inhibitors of medicinally relevant proteases might serve as tools for the elucidation of basic biological questions concerning regulation, timing and spatiotemporal control of such key processes as virus maturation or cancer development. The experimental work described in this thesis summarizes my results in both these areas. Human Immunodeficiency Virus Protease Human immunodeficiency virus (HIV), a causative agent of AIDS, has been estimated to kill close to 40 million people during the past four decades with 1.5...
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