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Now showing items 11-18 of 18
Dissertation
The tRNA binding protein Kti12 and its role in the regulation of Elongator complex
(2020-06-08)
[Summary] Kti12 is a conserved eukaryotic protein showing sequence homology to O-phosphoseryltRNA kinase (Pstk), which is required for the synthesis of selenocysteine tRNA. Saccharomyces cerevisiae Kti12 was originally discovered in a genetic screening for resistance against zymocin, a protein toxin produced by Kluyveromyces lactis. The cytotoxicity of zymocin lies in its anticodon nuclease activity, causing tRNA depletion and cell death in sensitive yeast cells. It recognizes and cleaves a particular wobble uridine ...
Dissertation
Association of neighboring β-Strands to form the β-barrel structure of the voltage-dependent anion channel, human isoform 1 (hVDAC1) precedes membrane insertion and is largely driven by polar interactions between basic and acidic amino acid side-chains
(2020)
To date, all biophysical folding studies on β-barrel membrane proteins from outer membranes (OMPs) indicated a coupled mechanism of folding and membrane insertion. Most of these studies were performed with smaller OMPs from bacteria. Here we have investigated folding and insertion of a mitochondrial OMP, the voltage-dependent anion-selective channel (VDAC), human isoform 1 (hVDAC1). To examine whether folding and insertion are coupled for hVDAC1, the association of neighboring β-strands of the 19-stranded β-barrel ...
Dissertation
Regulatory mechanisms of Protein kinase A - Isoform mediated fine-tuning
(2023)
cAMP-dependent protein kinase (PKA) is a crucial part in eukaryotic signal transduction and controls biological processes. With a multitude of substrates, a great variety of cellular functions are regulated by PKA. Regulation of metabolism, cell growth and -differentiation, conductivity of ion channels, movement of sperm cells, embryonic development, neuroplasticity as well as conversion of short- to long-term memory are just examples for the many tasks of the kinase. To achieve and coordinate these diverse functions, ...
Dissertation
Populationsgenetik und Phylogeographie des Großen Immergrüns (Vinca major L.; Apocynaceae) im autochthonen vs. allochthonen Verbreitungsgebiet
(2023-04-21)
Populationsgenetik und Phylogeographie des Großen Immergrüns (Vinca major L.; Apocynaceae) im autochthonen vs. allochthonen Verbreitungsgebiet
Das Große Immergrün (Vinca major L., Apocynaceae) stammt aus dem Mittelmeerraum und wurde durch den Menschen als Nutz-, Arznei- und Zierpflanze sowie wegen seiner mythologischen Bedeutung in zahlreiche zuvor unbesiedelte Gebiete verschleppt. In einigen Regionen des allochthonen Areals (Australien, Neuseeland, USA) gilt V. major als invasiv und wird massiv bekämpft. Ziel ...
Dissertation
Pathogenic Mutations in Catalytic Subunit Isoforms of the cAMP-Dependent Protein Kinase
(2023)
Protein kinase A (PKA) is an integral part in a myriad of cellular pathways and a main effector of the second messenger cAMP. Since its discovery in the late 1960s, PKA has become one of the best-studied eukaryotic protein kinases in terms of enzymatic and structural features. Pathological implications of PKA have just started to emerge. There are three main isoforms (α, β, γ) of the catalytic subunit of PKA (PKA-C) which constitute a holoenzyme (R2C2) by association with a regulatory subunit (PKA-R) dimer. While ...
Dissertation
Biochemical Characterization of Microtubule-Associated Serine/Threonine Kinases
(2023)
The association of human microtubule-associated serine/threonine (MAST) kinases with different diseases, such as neurodevelopmental disorders and cancer, leads to hight interest in understanding the function of these understudied kinases. This PhD thesis provides the first consolidated biochemical analysis of three different human MAST kinases (MAST1-3) and the Drosophila melanogaster homologue drop out protein (DOP).
Dissertation
Functional Analysis of Src42A in embryonic epithelial morphogenesis of Drosophila melanogaster
(2023)
Src42A is one of the Src family kinases (SFKs) present in Drosophila melanogaster. In mammals there are 8 SFKs and so far, a loss of function analysis of SFKs were difficult to conduct due to their functional redundancy. In Drosophila, there are only two SFKs namely Src42A and Src64B, the former is essential for embryonic development and the latter is a non-essential gene. Since Src42A is supplied as a maternal component, the zygotic mutant were showing defects in later developmental stages, because the contribution ...
Dissertation
Functional analyses of Dph1•Dph2 in synthesis of diphthamide, a clinically relevant modification on eEF2
(2024)
Diphthamide is a unique post-translational modification of a conserved histidine on the eukaryotic translation elongation factor 2 (eEF2). During translation elongation, eEF2 induces translocation of codon-anticodon duplexes across the ribosomal decoding center. Diphthamide is involved in fine-tuning of this process by stabilizing the codon-anticodon duplex and maintaining reading frame accuracy. Initially, diphthamide was identified as the target for diphtheria toxin, enabling ADP-ribosylation of eEF2 and resulting ...