Biochemistry Commons^™

Micro-Spectroscopy Of Bio-Assemblies At The Single Cell Level, Jeslin Kera

Honors Undergraduate Theses

In this thesis, we investigate biological molecules on a micron scale in the ultraviolet spectral region through the non-destructive confocal absorption microscopy. The setup involves a combination of confocal microscope with a UV light excitation beam to measure the optical absorption spectra with spatial resolution of 1.4 μm in the lateral and 3.6 μm in the axial direction. Confocal absorption microscopy has the benefits of requiring no labels and only low light intensity for excitation while providing a strong signal from the contrast generated by the attenuation of propagating light due to absorption. This enables spatially resolved measurements of single …

Investigation Of The Mechanism Of Action For Mithramycin And The Biosynthesis Of L-Rednose In Saquayamycins, Stevi Weidenbach

Theses and Dissertations--Pharmacy

Natural products continue to be a major chemical lead matter for drug discovery due to their diverse chemical structures and bioactivities. Clinically significant natural products include anti-cancer and anti-infective compounds and while many more of these compounds show promising bioactivity, their clinical relevance is often limited by toxicity or poor solubility. Combinatorial biosynthesis can be employed to modify existing chemical scaffolds towards reducing these limitations. To fully take advantage of these biochemical tools, it is important to understand the biosynthesis and mechanism of action of the molecules.

Saccharides in glycosylated natural products provide specific interactions with cellular targets and are …

Functional Analysis Of Sin3 Isoforms In Drosophila, Nirmalya Saha

Wayne State University Dissertations

he multisubunit SIN3 complex is a global transcriptional regulator. In Drosophila, a single Sin3A gene encodes different isoforms of SIN3, of which SIN3 187 and SIN3 220 are the major isoforms. Previous studies have demonstrated functional non-redundancy of SIN3 isoforms. The role of SIN3 isoforms in regulating distinct biological processes, however, is not well characterized. In addition, how the components of the SIN3 complex modulate the gene regulatory activity of the complex is not well understood. In this study, I identified the biological processes regulated by the SIN3 isoforms. Additionally, I explored how Caf1-55 impacts the gene regulatory activity of …

Regulation Of Palmitoylation Enzymes And Substrates By Intrinsically Disordered Regions, Krishna D. Reddy

USF Tampa Graduate Theses and Dissertations

Protein palmitoylation refers to the process of adding a 16-carbon saturated fatty acid to the cysteine of a substrate protein, and this can in turn affect the substrate’s localization, stability, folding, and several other processes. This process is catalyzed by a family of 23 mammalian protein acyltransferases (PATs), a family of transmembrane enzymes that modify an estimated 10% of the proteome. At this point in time, no structure of a protein in this family has been solved, and therefore there is poor understanding about the regulation of the enzymes and their substrates. Most proteins, including palmitoylation enzymes and substrates, have …

Molecular Analysis Of Ftsz-Ring Assembly In E. Coli Cytokinesis, Kuo-Hsiang Huang

Dissertations, Theses, and Capstone Projects

An essential first step in bacterial division is the assembly of a cytokinetic ring (Z-ring) formed by the tubulin-like FtsZ at midcell. The highly conserved core domain of FtsZ has been reported to mediate assembly of FtsZ polymers in vivo and in vitro. Species-specific differences in the FtsZ C-terminal domain such as the FtsZ CTV region and interactions with several modulatory proteins such as ZapC and ZapD, restricted to certain bacterial classes, also serve as key determinants of FtsZ protofilament bundling. Here, we characterize (i) the roles of the FtsZ CTV region in mediating both longitudinal and lateral interactions …

Investigation Of A Mycobacteriophage Transcription Repressor, Kathryn Orban

Honors Thesis

Mycobacteriophage HelDan is a lysogenic, or temperate, phage (virus) of the bacterium Mycobacterium smegmatis, which is a fast-growing, close relative of Mycobacterium tuberculosis, the causative agent of tuberculosis. The phage replication cycle is dependent on time-coordinated gene expression events. In order to study the regulation of gene expression during phage replication, HelDan protein gp73, a putative transcriptional repressor, was studied. Characterization of gp73 structure and function, such as DNA binding activity and affinity, was done using both bioinformatics and biochemical analyses. To this end, the gene encoding gp73 was cloned and the ability of the recombinant gp73 protein …

Biophysical Studies Of The Allosteric Regulatory Mechanism Of Syk Tandem Sh2 Domains Interacting With Immunoreceptor Tyrosine-Based Activation Motifs, Chao Feng

Open Access Dissertations

The non-receptor spleen tyrosine kinase (Syk) is an important player in signal transduction from immunoreceptors to various downstream targets. It is widely expressed in both haematopoietic and epithelial cells. Syk disorder is closely related with many inflammatory and autoimmune diseases, as well as cancers.

Syk associates with immunoreceptors through its tandem SH2 domains (tSH2), which contain two SH2 domains connected by interdomain A. The association of Syk with immunoreceptors is regulated by Y130 phosphorylation in interdomain A. The unphosphorylated tSH2 can bind with the doubly phosphorylated immunoreceptor tyrosine-based activation motif (dp-ITAM) of the cytoplasmic domains of immunoreceptors with very high …

Identifying Non-Classical Active Sites As A Tool For Enzyme Inhibition, Marisol Serrano

Open Access Theses & Dissertations

Chagas disease, caused by the parasite Trypanosoma cruzi, is an endemic life-threatening disease that affects mainly the heart. It remains the leading cause of heart failure in Latin American countries. Since current treatments against this parasite are highly toxic and somewhat ineffective, novel and more efficacious types of interventions are desired. Cruzain, identified as the major cathepsin for T. cruzi, plays a major role in the parasite's life cycle; making this enzyme very attractive for potential trypanocidal drugs discovery. The recombinant cruzain is synthesized as a zymogenic pro-protein (PCZN) which possesses a pro domain and a catalytic domain. In this …

Characterization Of Hemerythrin-Like Protein Rv2633c, Michelle D. Cherne

Honors Undergraduate Theses

Hemerythrin-like protein Rv2633c is a small 18 kDa protein that is expressed in Mycobacterium tuberculosis (Mtb). Sequence analysis of Rv2633c predicts the presence of a hemerythrin-like domain, which binds dioxygen using a µ-oxo-bridge (Fe-O-Fe), rather than a heme group. Though it is noticeably upregulated during macrophage infection and during in vitro acidification, the role of Rv2633c in Mtb survival has yet to be elucidated. This project aims to characterize the function of Rv2633c by studying the in vitro response of the recombinant protein to conditions present in the macrophage lysosome, such as reduced oxygen levels or the …

Attempted Identification Of The Calcium-Dependent Sodium Channel Gene In Paramecium Tetraurelia Using Rnai, Gwendolyn Kuzmishin

Senior Independent Study Theses

Ion channels play an important role in the swimming behavior of Paramecium tetraurelia. Electrophysiological experiments indicate that a calcium-dependent sodium channel exists in Paramecium, but a gene has not been identified for this channel. It is hypothesized that this channel evolved from a voltage-dependent sodium channel after a whole genome duplication event. In this paper, 13 candidate genes were identified from the Paramecium genome based on their similarity to a reference human voltage-dependent sodium channel. Bioinformatics analysis of the selectivity filter of these putative ion channel genes suggested that at least 8 of the candidate genes were sodium channels …

A Pipeline For Creation Of Genome-Scale Metabolic Reconstructions, Shaun W. Norris

Theses and Dissertations

The decreasing costs of next generation sequencing technologies and the increasing speeds at which they work have lead to an abundance of 'omic datasets. The need for tools and methods to analyze, annotate, and model these datasets to better understand biological systems is growing. Here we present a novel software pipeline to reconstruct the metabolic model of an organism in silico starting from its genome sequence and a novel compilation of biological databases to better serve the generation of metabolic models. We validate these methods using five Gardnerella vaginalis strains and compare the gene annotation results to NCBI and the …

Deep Models For Brain Em Image Segmentation: Novel Insights And Improved Performance, Ahmed Fakhry, Hanchuan Peng, Shuiwang Ji

Computer Science Faculty Publications

Motivation: Accurate segmentation of brain electron microscopy (EM) images is a critical step in dense circuit reconstruction. Although deep neural networks (DNNs) have been widely used in a number of applications in computer vision, most of these models that proved to be effective on image classification tasks cannot be applied directly to EM image segmentation, due to the different objectives of these tasks. As a result, it is desirable to develop an optimized architecture that uses the full power of DNNs and tailored specifically for EM image segmentation.

Results: In this work, we proposed a novel design of DNNs for …

Characterizing Migratory Signaling Pathways Of Transplantable Retinal Progenitor Cells And Photoreceptor Precursor Cells Toward Restoration Of Degenerative Retina ' A Systems Biology Approach, Uchenna John Unachukwu

Dissertations, Theses, and Capstone Projects

A common feature of several heterogeneous diseases that result in retinal degeneration (RD) is photoreceptor loss, leading to an irreversible decline in visual function [15-17]. There are no cell replacement treatments available for RD diseases such as age-related macular degeneration (AMD) and retinitis pigmentosa (RP). Although many RD cases are of a genetic origin, a promising strategy to treat diseased phenotypes is by replacing lost photoreceptor cells, for synaptic integration and restoration of visual function. To advance photoreceptor-replacement strategies as a practical therapy, in light of highly restricted integration rates reported across studies, this body of research focused on defining …

Investigating The Interaction Of Aurka And Ube2c In Colorectal Cancer Cells, Apurva M. Hegde

Dissertations and Theses (Open Access)

Colorectal cancer (CRC) is the third leading cause of cancer-related deaths in the US. Among the many genomic aberrations previously implicated in colorectal cancer, recurrent amplification of chromosome 20q is frequently associated with liver metastasis. Previous research in our lab identified a gene signature on chromosome 20q associated with colorectal cancer progression. In this study, one of the genes in the signature, the ubiquitin conjugating enzyme UBE2C, was identified through preliminary bioinformatics analysis as a candidate for further examination of its role in CRC progression. Co-expression analysis of UBE2C in tumor-normal datasets from the public database Oncomine revealed all the …

Three-Dimensional Ideal Gas Reference State Based Energy Function, Avdesh Mishra

LSU New Orleans Theses and Dissertations

Energy functions are found to be a key of protein structure prediction. In this work, we propose a novel 3-dimensional energy function based on hydrophobic-hydrophilic properties of amino acid where we consider at least three different possible interaction of amino acid in a 3-dimensional sphere categorized as hydrophilic versus hydrophilic, hydrophobic versus hydrophobic and hydrophobic versus hydrophilic. Each of these interactions are governed by a 3-dimensional parameter alpha used to model the interaction and 3-dimensional parameter beta used to model weight of contribution. We use Genetic Algorithm (GA) to optimize the value of alpha, beta and Z-score. We obtain three …

Exploring The Effect Of Climate Change On Biological Systems, Nardos Sori

Chemistry & Biochemistry Theses & Dissertations

The present and potential future effect of global warming on the ecosystem has brought climate change to the forefront of scientific inquiry and discussion. For our investigation, we selected two organisms, one from cyanobacteria and one from a cereal plant to determine how climate change may impact these biological systems. The study involved understanding the physiological and adaptive responses at both the genetic and protein function levels to counteract environmental stresses. An increase in atmospheric carbon dioxide is a key factor in global climate change and can lead to alterations in ocean chemistry. Cyanobacteria are important, ancient and ubiquitous organisms …

The Structural Heterogeneity And Dynamics Of Base Stacking And Unstacking In Nucleic Acids, Ada Anna Sedova

Legacy Theses & Dissertations (2009 - 2024)

Base stacking provides stability to nucleic acid duplexes, and base unstacking is involved in numerous biological functions related to nucleic acids, including replication, repair, transcription, and translation. The patterns of base stacking and unstacking in available nucleic acid crystal structures were classified after separation into their individual single strand dinucleotide components and clustering using a k-means-based ensemble clustering method. The A- and B-form proximity of these dinucleotide structures were assessed to discover that RNA dinucleotides can approach B-form-like structures. Umbrella sampling molecular dynamics simulations were used to obtain the potential of mean force profiles for base unstacking at 5'-termini for …

Hiv Integrase Mechanisms Of Resistance To Raltegravir, Elvitegravir, And Dolutegravir, Kyla Nicole Ross

Wayne State University Theses

ABSTRACT

HIV INTEGRASE MECHANISMS OF RESISTANCE TO RALTEGRAVIR, ELVITEGRAVIR, AND DOLUTEGRAVIR

by

KYLA ROSS

December 2015

Advisor: Dr. Ladislau Kovari

Major: Biochemistry and Molecular Biology

Degree: Master of Science

HIV-1 integrase (HIV-1 IN or IN) is a multimeric enzyme that integrates the HIV-1 genome into the chromosomes of infected CD4+ T-cells. Currently there are three FDA approved HIV-1 IN strand transfer inhibitors (INSTIs) used in clinical practice: raltegravir (RAL), elvitegravir (ELV), and dolutegravir (DTG). The [Q148H], [Q148H, G140S], [Q148R], [Q148R, G140A] and [N155H, E92Q] mutations decrease IN susceptibility to RAL and ELV and may result in therapeutic failure. As an …

Dysregulation Of Micrornas In Blood As Biomarkers For Diagnosing Prostate Cancer, Rhonda W. Daniel

Theses and Dissertations

Prostate cancer is the most common noncutaneous cancer among men, yet current diagnostic methods are insufficient and more reliable diagnostic markers need to be developed. The answer that can bridge this gap and enable more efficient diagnoses may lie in microRNAs. These small, single stranded RNA molecules impact protein expression at the translational level and regulate important cellular pathways. Dysregulation of these small RNA molecules can have tumorigenic effects on cells and lead to many types of cancers.

Currently the Prostate-Stimulating Antigen (PSA) is used as a diagnostic marker for prostate cancer. However, many factors can elevate PSA levels such …

Mapping The Human Vasculature By In Vivo Phage Display, Julianna Bronk

Dissertations and Theses (Open Access)

In vivo phage display screenings by intravenous injection of a random phage-displayed peptide library allow for the selection of peptides that localize to specific vascular beds. At the University of Texas MD Anderson Cancer Center, we have had the opportunity to perform phage display screenings in cancer patients in order to select for cancer specific targets directly in humans. These targets serve to define biochemical diversity of endothelial cell surfaces and can be validated and explored towards the design of vascular-targeted pharmacology. In the most recent patient screen, samples were recovered from hepatocellular carcinoma (HCC) as well as 26 additional …

Experimental And Computational Analysis Of The Synucleins, Agatha Munyanyi

Theses and Dissertations in Biomedical Sciences

The synuclein proteins α, β and γ which are located in the brain, have been a subject of intense research. Of particular interest is α-synuclein, which is found in misfolded forms in Lewy bodies that are associated with Parkinson's disease. Despite the efforts of researchers across the world, the physiological structure and function of the synucleins remains elusive. In recent years, highly controversial reports by some investigators indicate that in its natural form, α-synuclein exists as a tetramer instead of as an intrinsically unstructured monomer. This dissertation presents results of the experimental and computational analysis of the synucleins. First, we …

Validation Of Predicted Mrna Splicing Mutations Using High-Throughput Transcriptome Data, Coby Viner, Stephanie Dorman, Ben Shirley, Peter Rogan

Biochemistry Publications

Interpretation of variants present in complete genomes or exomes reveals numerous sequence changes, only a fraction of which are likely to be pathogenic. Mutations have been traditionally inferred from allele frequencies and inheritance patterns in such data. Variants predicted to alter mRNA splicing can be validated by manual inspection of transcriptome sequencing data, however this approach is intractable for large datasets. These abnormal mRNA splicing patterns are characterized by reads demonstrating either exon skipping, cryptic splice site use, and high levels of intron inclusion, or combinations of these properties. We present, Veridical, an in silico method for the automatic validation …

Ether Bridge Formation And Chemical Diversification In Loline Alkaloid Biosynthesis, Juan Pan

Theses and Dissertations--Plant Pathology

Loline alkaloids, found in many grass-Epichloë symbiota, are toxic or feeding deterrent to invertebrates. The loline alkaloids all share a saturated pyrrolizidine ring with a 1-amine group and an ether bridge linking C2 and C7. The steps in biosynthesis of loline alkaloids are catalyzed by enzymes encoded by a gene cluster, designated LOL, in the Epichloë genome. This dissertation addresses the enzymatic, genetic and evolutionary basis for diversification of these alkaloids, focusing on ether bridge formation and the subsequent modifications of the 1-amine to form different loline alkaloids.

Through gene complementation of a natural lolO mutant and comparison …

Development Of Tyrosine Kinase Peptide Biosensors And Methods For Detection, Andrew Michael Lipchik

Open Access Dissertations

New methods to monitor tyrosine kinase activity are critical for studying kinases in cell biology, drug discovery and the clinic. Peptide-based biosensors for detection of kinase activity utilitize a kinase specific artificial peptide substrate, which can report intercellular kinase activity through the incorporation of phosphate.

An artificial Syk substrate peptide was developed and incorporated with other functional modules to produce a Syk biosensor. These modules included a biotin-tag for affinity capture, a photo-cleavable amino acid to allow release of the substrate from the delivery module and the cell penetrating peptides TAT. A live cell kinase assay utilizing this biosensor was …

Preservation Of Biosignature Molecules In Potential Sample Return Container Of The Mars 2020 Mission, Kimberly E. Lykens, Fei Chen Ph.D

STAR Program Research Presentations

Preservation of Biosignature Molecules in Potential Sample Return Container of the Mars 2020 Mission

Kimberly Lykens¹ and Fei Chen²

¹Wittenberg University, Springfield, Ohio 45501 ²Jet Propulsion Laboratory, Pasadena, California, 91109

One requirement for sustainable life on terrestrial planets includes the presence of organic polymers, compounds that are essential for major biological functions such as replication and catalysis. An identified goal of the Mars mission in the year 2020 is to implement a sample-return to identify and validate signs of life on Mars through the discovery of biosignature molecules in Martian core samples. Martian core samples recovered …

How Long Is A Piece Of Loop?, Yoonjoo Choi, Sumeet Agarwal, Charlotte M. Deane

Dartmouth Scholarship

Loops are irregular structures which connect two secondary structure elements in proteins. They often play important roles in function, including enzyme reactions and ligand binding. Despite their importance, their structure remains difficult to predict. Most protein loop structure prediction methods sample local loop segments and score them. In particular protein loop classifications and database search methods depend heavily on local properties of loops. Here we examine the distance between a loop's end points (span). We find that the distribution of loop span appears to be independent of the number of residues in the loop, in other words the separation between …

Utilizing Nmr Spectroscopy And Molecular Docking As Tools For The Structural Determination And Functional Annotation Of Proteins, Jaime Stark

Department of Chemistry: Dissertations, Theses, and Student Research

With the completion of the Human Genome Project in 2001 and the subsequent explosion of organisms with sequenced genomes, we are now aware of nearly 28 million proteins. Determining the role of each of these proteins is essential to our understanding of biology and the development of medical advances. Unfortunately, the experimental approaches to determine protein function are too slow to investigate every protein. Bioinformatics approaches, such as sequence and structure homology, have helped to annotate the functions of many similar proteins. However, despite these computational approaches, approximately 40% of proteins still have no known function. Alleviating this deficit will …

Ring Domain, David J. Hall

Protein Domains

Ring domain #1CHC. The RING finger is a specialized type of Zn finger consisting of 40–60 residues that binds two atoms of zinc, and is involved in mediating protein—protein interactions. Many zinc fingers bind nucleic acids. The presence of a RING finger domain is a characteristic of RING-class E3 ubiquitin protein ligases capable of transferring ubiquitin from an E2 enzyme to a substrate protein.

Sh2 Domain, David J. Hall

Protein Domains

SH2 domain #1BFJ. Src-homology 2 (SH2) domains are modules of ~100 amino acids that bind to specific phospho tyrosine (pY) containing peptide motifs. Conventional SH2 domains have a conserved pocket that recognizes pY, and a more variable pocket that binds 3-6 residues C-terminal to the pY and confers specificity.

Sh3 Domain, David J. Hall

Protein Domains

SH3 domain #1NEB. Src-homology 3 (SH3) domains bind to Pro-rich peptides that form a left-handed poly-Pro type II helix, with the minimal consensus Pro-X-X-Pro. Each Pro is usually preceeded by an aliphatic residue. Each in the aliphatic-Pro pair binds to a hydrophobic pocket on the SH3 domain.