Simplified Abstract

In this thesis, proteasomes – enzymes that break down proteins in the body – were studied. For this purpose, different mutations were introduced into the proteins that form the proteasomes, and their effects on function and structure were analyzed. To this end, the proteins were first produced in bacteria and then purified to obtain the desired protein in such a high concentration that it formed crystals under certain conditions.

This way, it was possible to determine which mutations reduced the activity of the proteasomes strongly and thus which residues or amino acids are particularly important for the ability of the proteasome to cleave proteins. We also tested which conditions (buffer, pH, protein concentrations, etc.) led to favorable results during purification and crystallization for all the individual proteins and which proteins were not capable of forming crystals on their own.