Physical Sciences and Mathematics Commons^™

Investigating Hfq-Mrna Interactions In Bacteria, Martha Audra Faner

Wayne State University Dissertations

Regulatory RNAs (sRNAs) are essential for bacteria to thrive in diverse environments and they also play a key role in virulence [11]. Trans-sRNAs affect the stability and/or translation of their target mRNAs through complementary base-pairing. The base-pairing interaction is not perfect and requires the action of an RNA binding protein, Hfq. Hfq facilitates these RNA-RNA interactions by stabilizing duplex formation, aiding in structural rearrangements, increasing the rate of structural opening, and/or by increasing the rate of annealing [18-21]. Hfq has two well characterized binding surfaces: the proximal surface, which binds AU rich stretches typical of sRNAs, and the distal surface, …

Single-Molecule Studies Of Local And Global Nucleic-Acid Dynamics, Eric Muthuri Patrick

Wayne State University Dissertations

Nucleic acids undergo both global and local conformational changes that are important for their function. Structural studies have over the decades been invaluable in elucidation of various biomolecular mechanisms, hence contributing significantly to the understanding of biological events. However, a clear understanding of how molecules function in the cellular context requires investigation of their interconversion between multiple conformations, including mapping the folding landscape and any coupled changes in conformation. Work in this thesis focuses on fluorescence experiments, mainly at a single-molecule level to investigate such processes.

First, a novel single-molecule approach is described focusing on local dynamics within nucleic acids …

Towards Personalized Medicine Using Systems Biology And Machine Learning, Calin Voichita

Wayne State University Dissertations

The rate of acquiring biological data has greatly surpassed our ability to interpret it. At the same time, we have started to understand that evolution of many diseases such as cancer, are the results of the interplay between the disease itself and the immune system of the host. It is now well accepted that cancer is not a single disease, but a “complex collection of distinct genetic diseases united by common hallmarks”. Understanding the differences between such disease subtypes is key not only in providing adequate treatments for known subtypes but also identifying new ones. These unforeseen disease subtypes are …

Development Of Peptide Inhibitors Targeting Clostridium Difficile Toxins A/B And Characterizing The Regulatory Role Of A Putative Negative Regulator Tcdc In Clostridium Difficile Toxin Gene Expression, Sanofar Jainul Abdeen

Wayne State University Dissertations

Clostridium difficile infections cause one of the most common and vital hospitalacquired

diseases often associated with broad-spectrum antibiotic usage. TcdA and TcdB

are the key virulence factors involved in major patho-physiology. While standard

antibiotics provide some respite, due to the high relapse rates and the emergence of more

severe disease presentations, antibiotics alone have often proven to be suboptimal.

Therefore there is a desperate need to develop an effective non-antimicrobial

therapeutics. Part of this work focuses on identification and further characterization of

peptide therapeutic that target the major virulence factor TcdA/TcdB. Towards

development of mechanistic-based anti-toxin agent, phage display was …

Development And Optimization Of The First High Throughput In Vitro Fret Assay To Characterize The Saccharomyces Cerevisiae Gpi-T, Sandamali Amarasingha Ekanayaka

Wayne State University Dissertations

DEVELOPMENT AND OPTIMIZATION OF AN IN VITRO FRET ASSAY TO CHARACTERIZE THE SACCHAROMYCES CEREVISIAE GPI TRANSAMIDASE

By

SANDAMALI AMARASINGHA EKANAYAKA

December 2013

Advisor: Dr. Tamara L. Hendrickson

Major: Biochemistry

Degree: Doctor of Philosophy

The enzyme glycosylphosphatidylinositol transamidase (GPI-T) mediates the attachment of a glycosylphosphatidylinositol (GPI) anchor to the C-terminus of specific proteins to produce GPI anchored proteins. This post-translational modification is essential for viability of eukaryotic organisms. However, very little is known about GPI-T and its catalytic activity. Thus, the research described in this abstract was conducted to develop an in vitro assay to monitor GPI-T. A high-throughput assay for …

Synthesis And Application Of Atp Analogs For Phosphorylation-Dependent Kinase-Substrate Crosslinking, Satish Kumar Garre Venkata Raghavendra

Wayne State University Dissertations

Phosphorylation is an important post-translational modification that plays a key role in a variety of signaling cascades and cellular functions. Kinases phosphorylate protein substrates in a highly regulated manner and are promiscuous. Understanding kinase-substrate specificity has been challenging and there is a need for new chemical tools. To this end we developed -phosphate modified ATP photocrosslinking analogs ATP-ArN3 and ATP-BP, that crosslink substrate and kinase in a phosphorylation dependent manner. We have successfully demonstrated that ATP-ArN3 and ATP-BP can be used with natural kinase and substrates using cell lysates in vitro. We used our approach to identify novel kinases of …

Single-Stranded Dna Scanning And Deamination With Single-Molecule Resolution, Padhuk Gamarala Senavirathne

Wayne State University Dissertations

SINGLE-STRANDED DNA SCANNING AND DEAMINATION WITH SINGLE-MOLECULE RESOLUTION

by

GAYAN SENAVIRATHNE

December 2013

Advisor: Dr. David Rueda & Dr.Ashok Bhagwat

Major: Chemistry (Analytical)

Degree: Doctor of Philosophy

APOBEC3G (Apo3G) and Activation-Induced cytidine Deaminase (AID) are the most notable members of APOBEC enzymes, a family of cytidine (C) deaminases with crucial functions in the immune system. In T cells, Apo3G deaminates C in viral cDNA to halt the replication of HIV 1 strains lacking viral infectivity factor (vif). In B cells, AID is required for the diversification of antibodies through initiation of somatic hypermutation (SHM), and class switch recombination (CSR), by …

Computational Approaches To Anti-Toxin Therapies And Biomarker Identification, Rebecca Jane Swett

Wayne State University Dissertations

This work describes the fundamental study of two bacterial toxins with computational methods, the rational design of a potent inhibitor using molecular dynamics, as well as the development of two bioinformatic methods for mining genomic data.

Clostridium difficile is an opportunistic bacillus which produces two large glucosylating toxins. These toxins, TcdA and TcdB cause severe intestinal damage. As Clostridium difficile harbors considerable antibiotic resistance, one treatment strategy is to prevent the tissue damage that the toxins cause. The catalytic glucosyltransferase domain of TcdA and TcdB was studied using molecular dynamics in the presence of both a protein-protein binding partner and …