Chromatin provides the required structural compaction of DNA to fit in the cell nucleus. Chromatin function ultimately depends on the structural and dynamical properties of the nucleosome, its fundamental repeating unit. The nucleosome acts as a gate keeper by regulating the binding of proteins that carry out DNA-templated processes like transcription, replication and DNA repair.
The studies described in this thesis aimed to contribute to our basic understanding of chromatin structure and function, focusing on the contribution of the nucleosomal DNA. We investigated the fundamental design principles of the nucleosome, as well as those of a comparable chromatin complex in archaea, which might represent the evolutionary ancestor of a nucleosome.
Furthermore, we describe the role of DNA and the histone tails in activation of a protein that can move nucleosomes along DNA and thereby regulate gene expression. Finally, we developed an efficient approach to produce genomic nucleosomal DNA at a large scale and we describe new techniques to unlock the DNA within the nucleosome for nuclear magnetic resonance (NMR) studies.