Folding and Unfolding Mechanism of Designed Ankyrin Repeat Proteins

The ‘protein folding problem’, i.e. understanding the detailed steps of the protein folding pathways is one of the most challenging topics in biochemistry. Combining theoretical with experimental research became indispensable for the investigation of the mechanisms in protein folding reactions. Here, the biophysical characterization of designed ankyrin repeat (AR) proteins and the analysis of the experimental data by theoretical models are presented. Repeat proteins comprise repeating structural units that form linear multirepeat arrays. The non-globular elongated structure distinguishes them fundamentally from most studied proteins and makes repeat proteins interesting for folding studies. In a previous work, a full-consensus ankyrin repeat had been designed. Such an idealized ankyrin repeat served as a model repeat to study the folding mechanism of ankyrin repeat proteins.