Líffræðifélag Íslands - biologia.is
Líffræðiráðstefnan 2023
Höfundar / Authors: Mahtab Hafizi Yazdabadi (1), Kateryna Nitsenko (1), Niclas Ritter (1), Pétur Órri Heidarsson (1)
Starfsvettvangur / Affiliations: 1. University of Iceland
Kynnir / Presenter: Mahtab Hafizi Yazdabadi
The regulation of pivotal cellular processes that require interaction between nucleoproteins and DNA relies on the conformational plasticity of proteins lacking a well-defined folded structure. Among the first intrinsically disordered proteins (IDPs) that were known to affect chromatin structure are high mobility group (HMG) proteins. HMGA proteins are the most abundant non-histone chromatin remodellers and their competition with histone H1 results in the eviction of H1 from nucleosome structure. HMGA family has four intrinsically disordered isoforms, HMGA1a, b, c and HMGA2. The molecular mechanism through which HMGA proteins compete with H1 in nucleosome structure is still unclear. Thus, it is important to establish the kinetics of complex formation between HMGA and nucleosome. We have already reconstituted double-labelled nucleosomes based on the strong-positioning Widom 601 DNA sequence and conducted experiments with histone H1 and HMGA1 proteins to study HMGA1 kinetics on freely diffusing nucleosomes and surface immobilized nucleosomes. Our preliminary results suggest that HMGA1 competes with H1 in a concentration and salt dependant manner. Additionally, we will employ different isoforms of HMGA and monitor changes in binding kinetics (between different isoforms). To do so, we express and purify some HMGA isoforms which will be used in smFRET experiments with double-labelled nucleosome.