Optimization of a high throughput screening platform to identify inhibitors of asymmetric diadenosine polyphosphatases.

When stressed, cells synthesize di-adenosine polyphosphates (ApA), and cellular organisms also express proteins that degrade these compounds to release ATP. Most of these proteins are members of the nudix hydrolase superfamily, and several are involved in bacterial pathogenesis, neurodevelopment, and cancer. The goal of this project is to assist in the discovery of inhibitors of these enzymes that could be used to study ApA function and the cellular role of these nudix enzymes.

Kinetic and mutational studies of the adenosine diphosphate ribose hydrolase from Mycobacterium tuberculosis.

Mycobacterium tuberculosis represents one of the world's most devastating infectious agents - with one third of the world's population infected and 1.5 million people dying each year from this deadly pathogen. As part of an effort to identify targets for therapeutic intervention, we carried out the kinetic characterization of the product of gene rv1700 of M.

Insights into the substrate specificity of the MutT pyrophosphohydrolase using structural analogues of 8-oxo-2'-deoxyguanosine nucleotide.

The bacterial repair enzyme MutT hydrolyzes the damaged nucleotide OdGTP (the 5'-triphosphate derivative of 8-oxo-2'-deoxyguanosine; OdG), which is a known mutagen and has been linked to antibacterial action. Previous work has indicated important roles for the C8-oxygen, N7-hydrogen, and C2-exocyclic amine during OdGTP recognition by MutT. In order to gain a more nuanced understanding of the contribution of these three sites to the overall activity of MutT, we determined the reaction parameters for dGTP, OdGTP, and nine of their analogues using steady state kinetics.

Assessment of the reproductive status of female veiled chameleons (Chamaeleo calyptratus) using hormonal, behavioural and physical traits.

Egg binding is a common reproductive disorder in captive female reptiles leading to premature loss of breeding potential, or in severe cases death. It can result from failure to ovulate (and reabsorb) follicles; follicular stasis, or failure to lay eggs; dystocia. Reproductive status of female veiled chameleons (Chamaeleo calyptratus) in a research colony was assessed using enzyme immunoassay (EIA) of fecal reproductive hormones (estradiol; E2, progesterone; P, and testosterone; T) and their metabolites, ultrasound imaging of the reproductive tract, and receptivity to conspecific males.

Three new Nudix hydrolases from Escherichia coli.

Three members of the Nudix (nucleoside diphosphate X) hydrolase superfamily have been cloned from Escherichia coli MG1655 and expressed. The proteins have been purified and identified as enzymes active on nucleoside diphosphate derivatives with the following specificities. Orf141 (yfaO) is a nucleoside triphosphatase preferring pyrimidine deoxynucleoside triphosphates.