What is X-Ray

Secretases are aspartic proteases, which specifically trim important, medically relevant targets such as the amyloid-precursor protein (APP) or the Notch-receptor. Therefore, changes in their activity can lead to dramatic diseases like M. Alzheimer caused by aggregation of peptidic fragments. On the other hand, the secretases are interesting targets for molecular therapy of the multiple myeloma, because the over-expressed Notch-receptor does not emerge into the native conformation until the cleavage by the presenilin, the active and catalytic subunit of the gamma secretase, occurs. Here, we focus on a novel methodology of structure-based drug development, feasible without prior knowledge of the target structure— analogy modeling. This combination of similarity screening, fold recognition, ligand-supported modeling, and docking is exemplarily illustrated for the structure of presenilin and specific inhibitors thereof.