Research

Understanding transport across biological membranes

Active transport across biological membranes is a fundamental process in living systems that governs a plethora of biological processes such as the uptake of metabolites, energy generation, muscle movement, etc. In my group, we use solid state NMR spectroscopy along with other biophysical tools to decipher the mechanism by which membrane proteins achieve active and passive transport across membranes. Towards this goal, we also develop techniques in solid state NMR spectroscopy to study these challenging systems. The following sections will detail some of the work that is currently underway in our lab.

Structural and Mechanistic Characterization of the Mitochondrial Pyruvate Carrier

Pyruvate is a key intermediate in a number of metabolic pathways. It is the produced at the last step of glycolysis in the cytoplasm, and needs to be transported into mitochondria, where it is the starting product for the Krebs cycle. The identity of protein that effects this transport was an outstanding mystery in molecular biology for several decades. Recent studies have now identified hetero-oligomeric MPC complexes as essential and sufficient components of the mitochondrial pyruvate carrier assembly. The oligomeric assembly and structural features of these proteins that actually effect pyruvate transport are however, not known. Our immediate aim is to elucidate the structural features of MPC responsible for pyruvate transport and provide a structural basis for its inhibition by various known inhibitors. Our long term goal is to use these studies as a template in order to understand active transport by membrane proteins, as well as develop NMR techniques that can be applied to study other membrane proteins and their complexes.

Fast Data Acquisition Methods in solid state NMR

NMR is an inherently insensitive technique, solid state NMR even more so, due to the presence of large spin interactions that cause fast relaxation. We are developing techniques in which multiple experiments can be done in the same time without any compromise in sensitivity. These multiple acquisition techniques have the potential to give time savings of the order of ~50% in most of the standard NMR experiments. This translates to weeks or months of saved time when dealing with membrane proteins in solid state NMR. We are currently working on combining these techniques with 1H-detection in the solid state using homonuclear decoupling and windowed acquisition techniques as well as multiple receivers to improve the sensitivity and applicability of this technique further.