Life Sciences Commons^™

Towards Understanding Osmolyte Effects On Folate(S) And Dihydrofolate Reductase Proteins, Purva Prashant Bhojane

Doctoral Dissertations

Osmolytes are small molecules that alter water activity and probe role of water in biological processes. Osmotic stress approach explored the role of water in ligand binding to dihydrofolate reductase (DHFR). DHFR catalyzes NADPH dependent reduction of dihydrofolate (DHF) to tetrahydrofolate (THF), which is essential for the synthesis of DNA, amino acids and other metabolic intermediates. R67 DHFR is a plasmid-encoded DHFR that confers resistance against trimethoprim, which is a potent inhibitor of E.coli chromosomal DHFR.

Osmolytes addition decreases the affinity of the substrate towards both the DHFRs. Weak preferential interactions between the osmolytes and DHF impede substrate binding to …

New Insights Into An Old Interaction: Developing A Model For Pai-1:Vn Interactions, Letitia Nichole Puster

Doctoral Dissertations

Active human Plasminogen Activator Inhibitor 1 (PAI-1) is most often found in complex with Vitronectin (VN), an ~62kDa glycoprotein. Research has shown PAI-1 and VN form higher order complexes in tissues, and our work indicates a 2:1 (PAI-1:VN) stoichiometry for these complexes. A logical model for PAI-1:VN interaction proposes that two PAI-1 molecules bind VN at separate sites. However, our small-angle neutron scattering (SANS) data suggest that there is a PAI-1: PAI-1:VN interaction, in which PAI-1 forms a dimer when in complex with VN. We tested this novel arrangement of PAI-1 within the complex by using a variety of biophysical …