Biophysical Studies of Protein Folding, Assembly, Structure, and Stability

Overview of Research:
Role of environment, cofactors and assembly in protein folding; Copper-transport mechanisms in humans

The question of how a protein is formed is one of life's great mysteries. The understanding of protein folding and misfolding processes, and how external factors affect these reactions, are critical for finding rational treatment of many debilitating conditions like Alzheimers and Parkinson's disease, type II diabetes, prion diseases, and Menke's and Wilson's diseases. Knowledge about protein folding is also crucial in protein design and protein-structure prediction efforts. The projects in my lab focus on fundamental aspects of protein folding reactions using model systems (mechanistic path) as well as on specific human proteins involved in key metabolic pathways (medical path).

Some of my research aims to increase our fundamental knowledge of how proteins fold in vitro and in vivo. The major focus of this part is on two key classes of proteins: cofactor-binding proteins and oligomeric proteins. Folding of these proteins does not only involve polypeptide folding, but also inter-protein interactions. Folding pathways for these proteins may be affected by cofactor interactions and protein-protein interactions, respectively. Previous and/or ongoing/future projects focus on azurin (copper), flavodoxin (flavin), myoglobin (heme), co-chaperonin proteins (heptamers), and VlsE (dimer). To mimic the crowded cellular environment in vivo, experiments are performed in the presence of crowding agents.

Another branch of my research aims to understand the biophysical behavior of proteins involved in human cellular copper transport. Copper is an essential metal in many enzymes that is required from the diet. Since free copper ions are toxic, copper is specifically transported by proteins. Inside cells, copper chaperones deliver copper to Wilson and Menkes proteins in the Golgi network, which then load the metal onto targets, such as ceruloplasmin which is a plasma protein important for iron metabolism. Ongoing and future projects within this scope concerns the folding, binding and transfer properties of human and bacterial copper chaperones, different domains of the human Wilson protein as well as ceruloplasmin.

For all projects, a range of biophysical and biochemical techniques are combined with strategic protein mutagenesis and theoretical approaches to characterize the folding reactions of selected target proteins.