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Integrative structural biology employs not only high-resolution techniques for the determination of the structure of biomolecules. Information about dynamical and heterogeneous assemblies is hardly achievable with conventional approaches. Therefore, low-resolution techniques are being utilized. As mass spectrometry (MS) is sensitive, specific, and versatile, there are a lot of structural techniques based on MS established. Native mass spectrometry is an approach that uses non-denaturing solvents for nanoelectrospray ionization, thus preserving tertiary and quaternary structures in the gas phase. Therefore, information on the composition of native biomolecules is obtained. Moreover, employing ion mobility (IM-MS) also provides structural insight. Using MS, we can directly analyze biomolecules perturbation, such as by variable-temperature nanoelectrospray ionization (vT-nESI). The aim of this master's thesis was to characterize the thermal stability of the protein-DNA complexes of TEAD1 and FOXO4 transcription factors DNA-binding domains. Complexes were studied using native MS and IM-MS employing an in-house developed vT-nESI source. First, vT-nESI was used to determine the melting temperatures of double-stranded DNA, which were in correspondence with those theoretically calculated and experimentally...

Transcription factors from TEAD protein family play an important role in various eukaryotic regulatory processes. They are partly responsible for cell differentiation and apoptosis due to their involvement in the Hippo signalling pathway. Scientific interest in this protein family is mainly because they are associated with carcinogenesis. DNA-binding domain of TEAD transcription factors interacts with M-CAT element of double-stranded DNA, which is present also in enhancer and exon of C-MYC gene. Interaction between TEAD1 DNA-binding domain and C-MYC dsDNA was investigated in this bachelor's thesis mainly by ion mobility in connection with mass spectrometry using native nESI ionization. For the further analysis of TEAD1-DBD and its complexes with dsDNA, the protein was firstly recombinantly expressed by the optimized protocol in our laboratory. Investigation of TEAD1-DBD and its complexes was done using two IM-MS activations. Firstly, the collision-induced unfolding was performed and afterwards perturbation of the sample by preheating nESI emitter was done. The first activation led to the collision- induced unfolding of some charge states of TEAD1-DBD protein and both protein-DNA complexes. The second activation performed by heating of nESI emitters led to temperature melting of both dsDNA and...