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Structure Determination and Analysis of Terminal Uridylyltransferases by Means of XRay Crystallography for Trypanoside Development
Jessica G. Bruystens
Mentor: Hartmut Luecke
The development of new lead compounds as potential therapeutic agents for the treatment
of diseases that are caused by microorganisms comprises a major area of research in the
struggle against increased drug resistance. Such is the case for Human African
trypanosomiasis (HAT), often called sleeping sickness, which is caused by the protozoan
parasite Trypanosoma brucei. During the investigation of Trypanosomes, a new RNA
editing system was discovered in their kinetoplast-mitochondria, presenting new possible
targets for drug discoveries. We have been structurally analyzing a set of enzymes that
are involved in the RNA-editing process or that show sequence homology to the involved
enzymes, and have previously determined structures of UTP substrate-bound and apo
forms of TbTUT4, a minimal catalytically active RNA uridylyltransferase. To investigate
the TbTUT4 reaction of U transfer to the 3’ hydroxyl of mRNA, we have obtained a
UTP+TbTUT4+UMP prereaction complex and a postreaction complex of TbTUT4 with
UpU. The search for drug candidates has steered our TUTase investigation towards
obtaining a crystal structure of TbTUT4 bound with a small molecule inhibitor and to
elucidate the structures of TbMEAT-1, TbTUT9, and kPAP, which represent additional
potential drug targets. Here we report the progress and challenges in their crystal-based
structural investigation.