Biochemistry Commons^™

Functions Of The Dna Polymerase Delta Replicase In Lagging Strand Replication, Joseph L. Stodola

Arts & Sciences Electronic Theses and Dissertations

The work described in this dissertation focuses on several aspects of DNA replication in the model organism Saccharomyces cerevisiae, with particular attention paid to the function of the replicative DNA polymerase delta (Pol ), and its functions in Okazaki fragment synthesis and maturation. The first major theme of this dissertation is investigating the role that metal binding motifs play in the structure and function of Pol and other budding yeast polymerases. First, I discuss the role that two metal binding motifs within the catalytic subunit of Pol play in creating the multi-subunit polymerase complex and in promoting crucial interactions with …

Metal Selectivity And Acquisition By The Yersiniabactin Metallophore System In Escherichia Coli, Eun-Ik Koh

Arts & Sciences Electronic Theses and Dissertations

Urinary tract infections (UTI) are one of the most common bacterial infections, of which, the majority are caused by uropathogenic Escherichia coli (UPEC). Many bacterial pathogens including UPEC synthesize and secrete chemically diverse metabolites called siderophores, which are classically defined by their ability of bind and deliver iron(III), an essential nutrient, to pathogens during infections. UPEC isolates can express multiple siderophore systems, of which, the virulence-associated siderophore yersiniabactin (Ybt) binds to both iron(III) and copper(II) during urinary tract infections. In this thesis we show that Ybt interacts with multiple physiologic transition metals and acts as a metallophore system to deliver …

Mechanism Of Calcium-Dependent Chloride Channel Activation By The Secreted Regulator Clca1, Zeynep Yurtsever

Arts & Sciences Electronic Theses and Dissertations

The calcium-activated chloride channel regulator (CLCA) proteins are key signaling molecules, which are implicated in various diseases through their tissue-specific expression. Human CLCA1 protein, overexpressed in airway epithelia under pathophysiological conditions, is centrally involved in the manifestation of IL-13-driven mucus cell metaplasia (MCM), a hallmark feature of asthma and chronic obstructive pulmonary disease (COPD), for which there are currently no available therapeutics. Elucidating the poorly understood molecular basis of CLCA1 function is thus required to design specific inhibitors of CLCA1 activity to treat MCM in asthma and COPD.

Originally misannotated as ion channels, CLCA proteins are secreted soluble proteins that …

Structure And Dynamics Of A Small Multidrug Resistance Transporter, Emre, Chao Wu

Arts & Sciences Electronic Theses and Dissertations

EmrE is a small multidrug resistance transporter in E. coli. It effluxes a wide range of antibiotics, thus contributing to the evolving epidemic of drug resistance. Despite its small size, EmrE is a fully functional transporter making it an ideal model system for a comprehensive study of the multidrug transport mechanism. In the transport cycle, EmrE must alternate between outward- and inward-facing conformations upon substrate binding to translocate substrates across the membrane. High-resolution structures of EmrE in complex with substrates facing different sides of the membrane will shed light on the coupling mechanism between substrate binding and transport. However, the …

Modulation Of Human And Malarial Glucose Transporter Activity By Lipids And Small Molecules, Thomas E. Kraft

Arts & Sciences Electronic Theses and Dissertations

Glucose transport is a fundamentally important process for maintenance and regulation of cellular metabolism in all kingdoms of life. Despite their high importance, detailed examination of glucose transport proteins in humans and parasites through biochemical, biophysical and structural properties was greatly hampered by the inability to express, purify and reconstitute sufficient amounts of active transporters. This dissertation describes strategies that led to the first successful expression, purification, stabilization and functional reconstitution of active insulin-responsive GLUT4 transport protein. Furthermore, the work described herein establishes a requirement of anionic and conical lipids for full activity of the mammalian glucose transporters GLUT3 and …