Mette Homann Poulsen

September 2004 – August 2009: M.Sc. (pharm), Faculty of Pharmaceutical Sciences, University of Copenhagen

October 2009: Ph.D student, Department of Medicinal Chemistry, Faculty of Pharmaceutical Sciences, University of Copenhagen

Studies of glutamate receptors by unnatural mutagenesis

Background
The ionotropic glutamate (iGlu) receptors are key mediators of information in our brain, and are crucial for basic functions in the brain such as memory formation.  iGlu receptors consist of a membrane embedded ion-channel and an extracellular ligand-binding domain. The structure and function of the ligand-binding domain is very well characterized, primarily by X-ray crystallographic studies of artificial constructs. In contrast, the membrane-embedded ion channel domain is less characterized, thus the primary focus of this project is on structural and functional studies of the iGlu receptor ion channel using unnatural mutagenesis.

Unnatural mutagenesis enables incorporation of close analogs of encoded amino acids thereby allowing very fine-tuned studies of ligand-receptor interactions and protein function in general. The methodology allows changes of the protein backbone, specifically replacing the amide backbone with an ester backbone, thus the functional importance of carbonyl groups in the backbone can be addressed. Both of these approaches will be applied for studies of the iGlu receptor ion channel. A number of different methods have been developed, and in the Chemical Biology group one of these, the nonsense suppression mutagenesis, has been implemented, and will be applied in this project. The present study will focus on clarifying the determinants for various physiological characteristics of iGlu receptors, by substituting selected amino acids for exmple in the ion channel with close non-encoded analogs. In addition, we will incorporate backbone mutations in iGlu receptors, specifically introducing an amide-to-ester mutation.  In both cases these studies are combined with our extensive in-house experience with polyamine toxins as ion-channel blockers of iGlu receptors.

Main Supervisor:
Kristian Strømgaard, PhD.
Professor
Department of Medicinal Chemistry

Co-supervisor:
Anders Skov Kristensen, PhD.
Assoc. Professor
Department of Medicinal Chemistry