Group Research Areas

These enzymes are upregulated in aggressive hepatocellular carcinomas and in childhood neuroblastomas, and ODC provides feedback to the oncogene myc. However, only ODC has an FDA approved inhibitor, and high-throughput inhibitor screening of these enzymes has proven challenging due to the lack of development of applicable assays. Time-resolved crystallography, utilizing the recently developed Millisecond Mix-and-Quench Crystallography (MMQX) technique, will enable the observation of the intermediate structural enzyme states that occur during the catalytic reaction, which will improve our understanding of required motions for enzymatic activity. In parallel with the time-resolved crystallography experiments, we will also perform multi-temperature crystallography experiments to observe the conformational ensembles of the resting states of ODC, SPDS, and SPS to identify allosteric motions and ground state fluctuations with a variety of cofactors, substrates, and products bound. The newly gained structural information from these experiments will be used to inform computationally aided drug development.

The breakdown processes of amino acids are vital for renewal and growth of cells and maintaining homeostasis. Specific enzymes are required to perform these chemical reactions, and their activity must be kept in balance to prevent an over or under supply. Most amino acid catabolism reactions take place in the liver via transamination and deamination reactions. However, due to the bonding structure of some amino acids, other reactions must take place first to make the amino group available for these reactions. We are currently studying proline dehydrogenase and tryptophan 2,3-dioxygenase, the enzymes that perform the initial steps of proline and tryptophan catabolism respectively.

The Clinger group is interested in developing and applying new structural biology techniques to enable studying challenging problems. In particular, we develop time-resolved quenching methods to trap reaction intermediates for analysis via either spectroscopic or diffraction methods. As a postdoctoral researcher, Jonathan Clinger developed Millisecond Mix-and-Quench Crystallography (MMQX) a method for performing time-resolved crystallography using single crystals and standard synchrotron beamlines.

Active site gating loops are important features of many enzymes, allowing them to bind substrates and release products efficiently, while also stabilizing transition state complexes. Their inherent flexibility makes them more challenging to study via structure alone. We are combining crystallography, mutagenesis, and molecular dynamics simulations to better understand the energy landscapes of these functional and only partially ordered structures.