The
C.U.R.E.
at NKU

The cartoon at the right depicts the Na,K ATPase, a primary target of study in the McGill lab. Expression studies have focused on chimeras of rat Na,K ATPase and the related H,K ATPase. Students use classical molecular techniques to assemble chimeric cDNAs, to make mammalian expression constructs with these cDNAs, then to express the rat proteins in human HeLa cells. Studies of many different chimeras are at various stages of study.

A second line of research in the lab involves the study of tryptophan 2,3 dioxygenase (TDO) function in mouse brain and liver. Classic enzymology is used to measure the enzyme activity from liver. HPLC is used to measure serotonin levels in brain from mice whose TDO levels may be altered.

The synthesis of catalysts that activate molecules such as N₂ and CO has a long history and is of industrial importance. Jonas C. Peters of California Institute of Technology has been interested in preparing such catalysts from transition metals and ligands derived from 8-aminoquinoline. Such complexes are 16-electron systems and leave open a coordination site that can be occupied by small molecules. David A. Atwood of the University of Kentucky has prepared similar complexes between tin and salen type ligands. The ligands used by Peters and Atwood appear to be ideally suited for the purpose preparing complexes that can activate small molecules because they tie up four of the normal six coordination sites of the metal and their bulkiness can prevent solvent molecules from taking up the remaining coordination sites. Thus, the goal of this research is to prepare transition metal complexes of salen type ligands that could be used to activate small molecules. One such example is shown below:

Two areas of primary research are being done in my lab, in addition to fundamental LC and LC/MS separation work in support of various faculty and customer projects. One involves the development of an LC/MS separation method for the detection of nitroaromatic and nitroamine explosives in a wide variety of matrices. A few of the 14 compounds we have studied are shown below.

The second involves the analysis of various cyanobacterial toxins produced by various strains of freshwater algae. These toxins are quite lethal and have begun to be regulated in drinking water throughout the world. Work in our lab has involved the concentration and separation of as many of these toxins as possible in a single LC/MS run. The main toxin, Microcystin LR, is shown below. (Where R=CH₃ and the A=Leu in the figure below).

The primary goal of our research is the study of small molecule/enzyme interactions on the molecular level using a combination of experimental and computational approaches. Understanding the factors that determine an enzyme’s ability to interact with small molecules is of critical importance for the elucidation of many biological processes and in particular for the design of novel drugs.

We are using computer programs to predict how and with what affinity drug-like molecules bind to enzymes. These docking programs are used for virtual screening of large compound libraries for novel inhibitors which are then tested in bioassays. For example, the first figure depicts the potent inhibitor dibutyl hydroquinone computationally docked into the binding site of the enzyme sarco/endoplasmic reticulum calcium ATPase. Inhibitors of this particular enzyme are of potential use for chemotherapy of prostate cancer. The second figure shows a structure-activity relationship (QSAR) model capable of predicting the inhibitory potencies of cardiac glycoside inhibitors. These drugs are frequently prescribed for the treatment of congestive heart failure symptoms and they inhibit the enzyme sodium/potassium ATPase.