Strukturní flexibilita regulačního segmentu DNA

Abstract

Transcription of the genetic code is controlled by numerous proteins. Some of them, so-called transcription factors, bind to certain DNA regions possessing anomalous properties due to their specific and highly conservative base sequence. One of these DNA segments is SRE (Serum Response Element). The diploma work is linked to results of the previous study indicating that the structural flexibility of this segment, related to the CArG box sequence, plays a key role in its physiological activity. Our work is devoted to study of this DNA segment and its model sequential variants. The approach of accurate measurements of temperature dependent UV absorption spectra and their consecutive analysis by means of factor analysis techniques and difference spectra construction, the main part of which was also developed within the framework of this work, was employed. The results indicate that separate chains of SRE with various length form surprisingly stable hairpins, which in some cases prevail even in mixtures of both chains of the SRE segment over duplexes. By using a fitting to thermodynamic equilibrium equations, thermodynamic characteristics of temperature induced association and dissociation transitions of complexes, both intermolecular (duplexes) and intramolecular (hairpins), were obtained.