The architects of crenarchaeal chromatin : A biophysical characterization of chromatin proteins from Sulfolobus solfataricus

Understanding of chromatin organization and compaction in Archaea is currently limited. The genome of several megabasepairs long is folded by a set of small chromatin proteins to fit into the micron-sized cell. A first step in understanding archaeal chromatin organization is to study the action of individual chromatin proteins on DNA. Characterization of the architectural properties of these proteins is essential to understand how they shape and modulate the archaeal genome. This thesis describes the biophysical characterization of several chromatin proteins from the crenarchaeal model organism Sulfolobus solfataricus: Cren7, Sul7, Alba and Sso10a. The architectural properties of these proteins resemble those of their bacterial counterparts, suggesting that they could play a similar role in chromatin organization and global gene regulation.UBL - phd migration 201

The interplay between nucleoid organization and transcription in archaeal genomes

Macromolecular Biochemistr

Effect of Temperature on the Intrinsic Flexibility of DNA and Its Interaction with Architectural Proteins

The helical structure of double-stranded DNA is destabilized by increasing temperature. Above a critical temperature (the melting temperature), the two strands in duplex DNA become fully separated. Below this temperature, the structural effects are localized. Using tethered particle motion in a temperature-controlled sample chamber, we systematically investigated the effect of increasing temperature on DNA structure and the interplay between this effect and protein binding. Our measurements revealed that (1) increasing temperature enhances DNA flexibility, effectively leading to more compact folding of the double-stranded DNA chain, and (2) temperature differentially affects different types of DNA-bending chromatin proteins from mesophilic and thermophilic organisms. Thus, our findings aid in understanding genome organization in organisms thriving at moderate as well as extreme temperatures. Moreover, our results underscore the importance of carefully controlling and measuring temperature in single-molecule DNA (micromanipulation) experiments

Diverse architectural properties of Sso10a proteins: Evidence for a role in chromatin compaction and organization

Macromolecular Biochemistr