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Investigation Of The In Vivo Activity Of Ribosome-Targeting Peptides And Aminoglycosides In Escherichia Coli, Nisansala Sarangi Thilakarathne Muthunayake

Wayne State University Dissertations

The development of short peptides that specifically bind to higher-order structures of ribosomal RNA is one promising way to address the problem of antibiotic resistance. However, the poor correlation between in vitro and in vivo activities of these peptides is one of the major questions in antibiotic peptide research. Therefore, one of the main objectives of this dissertation work was to utilize a plasmid-based system to in vivo express ribosome-targeting peptides and study their direct inhibitory effects on bacteria. A specific plasmid system was optimized to in vivo express oncocin, a prolin-rich antimicrobial peptide and its variants in bacteria. Our …

The Development Of Peptide Ligands To Target H69 Rrna, Danielle Nicole Dremann

Wayne State University Dissertations

ABSTRACT

THE DEVELOPMENT OF PEPTIDE LIGANDS TO TARGET H69

by

DANIELLE NICOLE DREMANN

December 2015

Advisor: Prof. Christine S. Chow

Major: Chemistry (Biochemistry)

Degree: Doctor of Philosophy

In the development of peptide ligands to target H69, SPPS and ESI MS was used to determine if 1) peptides could bind to modified H69 and 2) if increased affinity for the target RNA could be enhanced with modification. An alanine and arginine scan was synthesized and tested for this determination. Selected peptides were then tested using biophysical techniques such as circular dichroism and isothermal titration calorimetry. An assay was also designed to …

Dna Aptamers Selected Against Wild-Type Helix 69 Ribosomal Rna And Their Implications In Combating Antibiotic Resistance, Sakina Miriam Hill

Wayne State University Dissertations

Outbreaks of advanced antibiotic-resistant strains of microbes have hastened the need to identify new viable molecular targets for the development of novel anti-infectives. For this purpose, helix 69 (H69, or m3a 19-nucleotide (nt) hairpin motif that is highly conserved throughout phylogeny and rich in modified nucleotides, including pseudouridine () and 3-methylpseudouridine (m3) was chosen as a potential target. Helix 69, which is located in domain IV of Escherichia coli 23S ribosomal RNA (rRNA), undergoes conformational changes when in close proximity to the decoding region of 16S rRNA and transfer RNAs (tRNAs) in the peptidyl-transferase center (PTC). Functionally, the exact biological …

Study Of Protein-Rna Interactions Using Fluorescence Resonance Energy Transfer (Fret) And Single-Molecule Fret, Rajan Lamichhane

Wayne State University Dissertations

In the cell, RNA and protein, interact to form ribonucleoprotein complexes (RNPs) that have vital structural, catalytic and regulatory roles. Despite their functional importance, the mechanistic details and dynamics of RNPs are poorly understood. Single-molecule Fluorescence Resonance Energy Transfer (smFRET) techniques that provide information about heterogeneity and dynamic behaviors of molecules have been developed to investigate inter- and intra-molecular interactions. Here we have used FRET in combination with smFRET to study three very different RNP systems.

Alternative splicing is a highly regulated biological process that plays a crucial role in proteomic diversity in eukaryotes. One splicing regulator, PTB, has been …

Method Development And Applications To Screening And Characterization Of Rrna-Targeting Small Molecules, Papa Nii Asare-Okai

Wayne State University Dissertations

A series of single ring aminoglycoside analogues was tested for binding to a model RNA representing the A site using electrospray ionization mass spectrometry (ESI-MS). Several of the synthetic analogues with low molecular weights were found to bind to the RNA with affinities comparable to the parental aminoglycoside neamine, with apparent dissociation constants in the low micromolar range. Salt dependence of the affinity constants for the single ring analogues revealed a predominantly electrostatic binding mode. Footprinting experiments revealed that one of the compounds (DHR23) has a similar binding site as the antibiotic paromomycin. DMS chemical probing results also suggest that …