Biochemistry Commons^™

Structure Of A Monomeric Photosystem Ii Core Complex From A Cyanobacterium Acclimated To Far-Red Light Reveals The Functions Of Chlorophylls D And F, Christopher J. Gisriel, Gaozhong Shen, Ming-Yang Ho, Vasily Kurashov, David A. Flesher

Faculty Publications

Far-red light (FRL) photoacclimation in cyanobacteria provides a selective growth advantage for some terrestrial cyanobacteria by expanding the range of photosynthetically active radiation to include far-red/near-infrared light (700-800 nm). During this photoacclimation process, photosystem II (PSII), the water:plastoquinone photooxidoreductase involved in oxygenic photosynthesis, is modified. The resulting FRL-PSII is comprised of FRL-specific core subunits and binds chlorophyll (Chl) d and Chl f molecules in place of several of the Chl a molecules found when cells are grown in visible light. These new Chls effectively lower the energy canonically thought to define the "red limit" for light required to drive photochemical …

Characterization Of L-Malic Acid-Capped Cds Quantum Dots And Examination Of The Nanoncrystal's Biosensor Ability, Andrei A. Potapenko

Honors Theses and Capstones

Ligand-capped quantum dots are microscopic semiconductors commonly used in biomedical research and therapy for cell imaging and drug delivery. Despite the abundance of in vivo applications, the nature of interactions between the nanocrystals and the amino acids comprising human proteins remains insufficiently investigated. In this work, we report on the synthesis, ligand exchange, and characterization of the L-malic acid-capped CdS quantum dots via various spectroscopic techniques. We also assess the ligand-capped nanocrystals as potential probes for some amino acids. We determine that in the presence of L-cysteine, the L-malic acid-capped CdS quantum dots fluorescence signal quenches drastically, thus indicating a …

Effect Of Allosteric Site Binding On Smyd2 Conformational Ensemble, Jacob Daniel Sobota

Wayne State University Theses

Molecular dynamics simulation allows for the simulation of proteins with precise control over what ligands are present at what sites. The conformational ensemble of a protein can be obtained from MD simulation with and without binding at an allosteric site and compared between to gain insight at what effects binding at an allosteric site has on a protein’s structure. SMYD2, a critical regulator of cellular processes, was recently found to have a novel secondary binding site with allosteric effects on its activity. The discovery of an allosteric site has implications for drug design in the inhibition of SMYD2 to treat …

Mhc Diversity Analysis Of Spheniscus Demersus For In Situ And Ex Situ Populations, Antonieta Van Den Berg Monsalve

Undergraduate Honors Thesis Projects

The South African Penguin has been listed as endangered by the International Union for Conservation of Nature. Major histocompatibility complex (MHC) alleles provide valuable statistics because of their variation in terms of vertebrate genomes and are pertinent to immune and reproductive health. A greater number of MHC alleles correlates with survivability of a population because the genes control the immune and reproductive systems. Legacy research by Otterbein alumni and Dr. Simon Lawrance studied MHC samples from wild, in situ, and captive, ex situ, penguin populations. By comparing these populations' major histocompatibility complexes through biostatistical analysis, contributions to conservation of the …

Function And Expression Of Ribonucleotide Reductase-Encoding Genes In Flavobacterium Johnsoniae, Hunter Scott Doheny

All Graduate Theses, Dissertations, and Other Capstone Projects

Ribonucleotide reductases (RNRs) are essential enzymes that are involved in DNA synthesis. While this makes them ideal targets for antiproliferative drugs, most known RNR targeting agents are nonspecific. This poses a problem when considering antimicrobials, but several groups of bacteria have RNRs that utilize unique mechanisms that could be exploited if fully understood. One such bacteria, Flavobacterium johnsoniae, has the gene for a class Id RNR with a novel activation mechanism. Class Id RNRs belong to the aerobic class I RNRs and seem to have a unique metallocofactor and activation mechanism involving superoxide and manganese. The goal of this research …

Exosomal-Long Non-Coding Rnas Journey In Colorectal Cancer: Evil And Goodness Faces Of Key Players, Nehal I. Rizk, Ahmed I. Abulsoud, Mohamed M. Kamal, Dina H. Kassem, Nadia M. Hamdy

Pharmacy

Exosomes are nano-vesicles (NVs) secreted by cells and take part in cell-cell communications. Lately, these exosomes were proved to have dual faces in cancer. Actually, they can contribute to carcinogenesis through epithelial-mesenchymal transition (EMT), angiogenesis, metastasis and tumor microenvironment (TME) of various cancers, including colorectal cancer (CRC). On the other hand, they can be potential targets for cancer treatment. CRC is one of the most frequent tumors worldwide, with incidence rates rising in the recent decades. In its early stage, CRC is asymptomatic with poor treatment outcomes. Therefore, finding a non-invasive, early diagnostic biomarker tool and/or suitable defender to combat …

Purification And Activity Assay Optimization Of Bacterial Catalase From Psychrobacter Koprana, Sydney Willis

Honors Program Theses

To date, catalase protein from bacterial species is not the most widely used commercial catalase. Catalase, the enzyme that breaks down hydrogen peroxide in most living organisms, is an invaluable enzyme in the food, agriculture, and pharmaceutical industries. In 2019, a novel species of a psychrotolerant bacterium was discovered in Cold Harbor, NY. This species, Psychrobacter koprana, exhibits highly active catalase. Preliminary data from activity assays demonstrates that P. koprana catalase has the same activity as commercially available catalase. After purification and activity assay optimization, the activity of this catalase has the potential to be more active than other easily …

The Role Of Shoc2 In Embryonic Development, Rebecca G. Norcross

Theses and Dissertations--Molecular and Cellular Biochemistry

The canonical ERK1/2 signaling cascade regulates cellular functions critical in vertebrate embryonic development such as proliferation, apoptosis, differentiation, and migration. Thus, its signals are controlled by a variety of mechanisms. Scaffold proteins are considered central to the mechanisms regulating the transmission of the ERK1/2 signals. Yet, their functions in development nor the molecular mechanisms by which they exert their control are not well understood.

This study focuses on the essential regulator of ERK1/2 signals during development – the scaffold protein Shoc2. Loss of Shoc2 leads to early embryonic lethality in mice and zebrafish. Germline mutations in the shoc2 gene result …

Cancer And Quiescence: Investigating How The Dream Complex And Retinoblastoma Regulate The Cell Cycle, Lydia Rotman

Dissertations, Master's Theses and Master's Reports

An estimated 1.9 million people in the United States will be diagnosed with cancer in 2022. Cancer is characterized by uncontrolled cell growth, resulting from loss-of-function of key cell cycle regulatory proteins. The retinoblastoma protein (pRb) and p130, are two proteins that regulate cellular entry into the cell cycle. Both pRb and p130 repress expression of cell cycle genes, with pRb interacting with and suppressing E2F-DP transcriptional activators and p130 assembling in the DREAM transcriptional repressor complex. When normal cells receive signals to enter the cell cycle, cyclin and cyclin-dependent kinase (CDK) complexes phosphorylate pRb and p130, causing both to …

A Multidisciplinary Characterization Of The Enzymology And Biology Of Reversible Glucan Phosphorylation In Toxoplasma Gondii , Robert Murphy

Theses and Dissertations--Molecular and Cellular Biochemistry

Toxoplasma gondii is an opportunistic, protozoan parasite of all warm-blooded animals, infecting roughly one-third of humans worldwide. Humans acquire infections by consuming T. gondii tissue cysts in undercooked meat or from oocysts shed in cat feces. Encysted parasites convert into rapidly growing tachyzoites that disseminate throughout the body, defining the acute phase of infection. Under host immune pressure, tachyzoites convert into bradyzoites that populate tissue cysts found in CNS or muscle tissue and persist for the lifetime of the host, defining the chronic phase of infection. Tissue cysts are responsible for transmission via carnivory, but also possess the ability to …

The Impact Of Plant Secondary Metabolites On Auxin And Cytokinin Signaling, Timothy E. Shull

Theses and Dissertations--Plant and Soil Sciences

Secondary metabolites are a broad class of specialized compounds that mediate plant-environment interactions and mitigate stress. It is increasingly clear that many phenylalanine-derived secondary metabolites are nearly indispensable for plant survival and that plants adjust their growth according to their secondary metabolic outputs. Consequently, many phenylalanine-derived secondary metabolites have influence over hormone activity. For instance, multiple phenylpropanoid intermediates and catecholamines alter the sensitivity of plants to the central hormone auxin, which in concert with cytokinin directs most aspects of plant growth and development. This dissertation reviews previous research on the influence of phenylpropanoid intermediates and catecholamines on plants, with a …

Tissue And Sex-Specific Rna Editing During Induced Acute Inflammation, Claire E. Nichols

Graduate Theses/Dissertations

A-to-I RNA editing is a process where select adenosine (A) nucleotides are deaminated by an editing enzyme, ADAR, to become inosines (I) in RNA transcripts. RNA editing can affect the sequence of the encoded protein and the regulation of the RNA. ADAR1 also plays a role in regulating innate immunity and its expression is upregulated during inflammation. Current data on the effects of increasing ADAR1 on RNA editing is limited, and most studies are completed only in male animals. We are interested in expanding RNA editing data to include female animals. Lipopolysaccharide (LPS) was used to induce acute inflammation and …

Investigation Of A Carbon Monoxide Dehydrogenase From An Uncultured Archaeon, Luke Moore

Dissertations, Master's Theses and Master's Reports

The Nickel based Carbon Monoxide Dehydrogenase (CODH) is an anaerobic metalloenzyme responsible for the reversible conversion of CO and water into CO2 and 2 protons and 2 electrons. This enzyme has importance in the environment as one of Earth’s first carbon fixation pathways, and for human uses as a potential source of biofuels and other commodity chemicals. CODH enzymes are present in a wide array of taxa, many of which are uncultured. In this study we express and purify the catalytic subunit (CooS) of the anaerobic CODH from an uncultured Hydrothermarchaeota JdFR-17 co-expressed with the nickel insertion accessory protein (CooC) …

The Role Of Charge On Dna Packaging And Integrity Within Reconstituted Peptide-Dna Assemblies, Ehigbai Oikeh

Theses and Dissertations--Chemistry

In nature, DNA exists primarily in a highly compacted form. The compaction of DNA in vivo is mediated by cationic proteins; histone in somatic nuclei and arginine-rich peptides called protamines in sperm chromatin. The packaging in the sperm nucleus is significantly higher than somatic nuclei resulting in a final volume roughly 1/20^th that of a somatic nucleus. This tight packaging results in a near crystalline packaging of the DNA helices. While the dense packaging of DNA in sperm nuclei is considered essential for both efficient genetic delivery as well as DNA protection against damage by mutagens and oxidative species, …

Structural Basis Of Bacterial Flagellin For Naip5 Binding And Nlrc4 Inflammasome Activation And The Mechanism Of Flagellin Induced Release Of Cytokines In Vivo, Jian Cui

Theses and Dissertations--Chemistry

The bacterial flagellum is a whip-like structure that protrudes from the cell membrane and is one of the most complex and dynamic biological molecular machines that propels bacteria to swim toward beneficial environments and the sites of infection. It is composed of a basal body, a hook, and a long filament. The flagellar filament contains thousands of copies of the protein flagellin (FliC) monomer arranged helically and ending with a filament cap composed of oligomer protein FliD. The overall structure of the filament core is preserved across bacterial species, while the outer domains exhibit high variability, and in some cases …

Alternative Splicing Regulates The Innate Immune Response To Viral Infection, Luke A. White

Graduate Student Theses, Dissertations, & Professional Papers

Rift Valley fever virus (RVFV) is a mosquito-borne RNA virus that infects humans and livestock in sub-Saharan Africa and the Arabian peninsula, causing disease ranging from a mild flu-like illness to liver damage, blindness, hemorrhagic fever, death, and, especially in livestock animals, high rates of abortive pregnancies. There is no approved vaccine for RVFV, and as a disease with a high rate of spread that causes severe illness, it is listed as a Category A pathogen by the USA CDC. A better understanding of RVFV’s molecular virology will be instrumental to combating RVFV as climate change causes its mosquito host …

Vaginal Microbiota Of Recurrent Bacterial Vaginosis Patients Under Oral Metronidazole Therapy: Prognosis Based On Specific Species Of Gardnerella And Other Bacterial Vaginosis Associated Species In Association With The Vaginal Microbiome, Ashomathi Ashok Sudhamathi Mollin

Wayne State University Theses

Bacterial Vaginosis (BV) is a state of vaginal dysbiosis in which BV-associated species displace the typically dominant species of Lactobacillus. This urogenital disease elevates the risk for complications such as pre-term birth, STDs and HIV. Currently, there is no consensus on the etiology of BV. Standard of care treatment is oral metronidazole; however, therapy has high rates of recurrence. Our previous qPCR study of recurrent BV patients (3+ episodes/year) found strong associations of Gardnerella_Gsp07, G. swidsinksii, and G. leopoldii with refractory and recurrent responses, and a robust recovery of Lactobacillus in remission patients. However, these findings were not applicable across …

Analysis Of The Antimicrobial Activity Of The Novel Chemotherapeutic Drug, Tpp1, Against Pseudomonas Aeruginosa And The Hydrogel Delivery Of Water-Soluble Antimicrobial Compounds, Alex Gasper

Senior Independent Study Theses

Cancer is one of the leading causes of death in the world, and it is commonly linked with bacterial infections that often complicate treatments. Recently, chemotherapeutics have been developed that are able to act as anti-cancer agents using delocalized lipophilic cations (DLCs) that are able to specifically target mitochondrial membranes of cancer cells. TPP1 is a newly developed chemotherapeutic drug that has activity against bladder cancer and melanoma cell lines in vitro. In order to determine if TPP1 has antimicrobial activity, TPP1 was tested against a common bacteria, Pseudomonas aeruginosa, to determine if antimicrobial activity was present. This testing was …

Discovery Of Inhibitors Of Peptidoglycan O-Acetyltransferase B (Patb) From Neisseria Gonorrhoeae, A New Potential Antibacterial Target, Stefen Stangherlin

Theses and Dissertations (Comprehensive)

Experts project that by 2050, 10 million lives will be lost annually as a result of antimicrobial resistant infections, surpassing all current leading causes of death, and costing the global economy $100 trillion USD on healthcare efforts. To promote research and development of novel antibiotics, the World Health Organization and Centers for Disease Control and Prevention released a list of priority pathogens regarded as serious or urgent threats of antimicrobial resistance. Many pathogenic bacteria, including several priority pathogens, produce O-acetylated peptidoglycan to establish infection and avoid host immune responses. Consequently, the enzymes responsible for producing O-acetylated peptidoglycan in Gram-negative pathogenic …

The Musashi Rna Binding Proteins Are Regulators Of Alternative Splicing And Protein Expression In Photoreceptor Cells, Fatimah Kh. Matalkah

Graduate Theses, Dissertations, and Problem Reports (ETD)

The Musashi (Msi) family of RNA binding proteins consists of two paralogs, Msi1 and Msi2, that are highly conserved across species. The two paralogs have emerged as factors that promote stem cell proliferation by post-transcriptionally regulating translation. In addition to their expression in stem cells, the Musashi proteins are also expressed in postmitotic neurons, including the photoreceptor cells. The Musashi proteins have been observed to maintain high expression levels in the postmitotic photoreceptors within the eye of both invertebrates and vertebrates. These observations suggest an additional role in the maintenance of terminally differentiated neurons.

Building upon these observations, we investigated …

Elucidating The Proteasomal Regulatory Mechanism Of Proteasome Activator Pa28Γ /Regγ, Taylor Ann Thomas

Graduate Theses, Dissertations, and Problem Reports (ETD)

Virtually all cellular processes are precisely regulated by the proteasome which is the primary enzyme responsible for the degradation of misfolded, damaged, or no longer necessary soluble proteins. To prevent any untimely degradation of these target protein substrates and protect the cell, the proteasome is tightly regulated via adaptor proteins, known as proteasomal regulators. There are many classes of proteasomal regulators each with their own unique structures, functions, and effects on protein degradation through the proteasome. One such class is the 11S family of proteasomal regulators which are also referred to as PA26/28, or REG. The 11S family are ATP-independent …

An Investigation Into The Mechanism Of Proteasome Dysfunction In Neurodegenerative Disease And The Biological Impact Of Proteasome Hyperactivation In C. Elegans, Raymond T. Anderson

Graduate Theses, Dissertations, and Problem Reports (ETD)

Aging is an inevitable process that occurs as humans grow older. It is characterized by the chronological accumulation of cellular damage over time leading to functional decline as an organism grows older. Several processes are thought to contribute to the aging phenomenon, but one of the most prolific of these is the disruption of protein homeostasis (proteostasis). The collapse of proteostasis can lead to accelerated aging and the development of age-related diseases including devastating neurodegenerative diseases (NDs) like Alzheimer and Parkinson disease. Virtually all NDs are characterized by the buildup of proteins in and around neurons resulting in neuronal death …

Transitions Between The Steps Of Group Iic Intron Forward And Reverse Splicing And Integration Into Dna, Claire Mae Smathers

Graduate Theses, Dissertations, and Problem Reports (ETD)

Group II introns are ancient ribozymes capable of self-excision and mobility into new genomic locations. As the ancestors of both the eukaryotic spliceosome and eukaryotic retroelements, these simple RNA machines serve as excellent models for understanding the mechanisms of both gene splicing and retroelement activity in eukaryotes. Although group II introns have been studied for decades, knowledge of the most unique and arguably evolutionarily relevant class of group II introns, IIC, is limited. Our knowledge is especially limited in terms of understanding how IIC introns mediate the transition between the two transesterification steps of forward splicing and reverse splicing into …

High-Resolution Cryo-Electron Microscopy Structure Of Photosystem Ii From The Mesophilic Cyanobacterium, Synechocystis Sp. Pcc 6803, Christopher J. Gisriel, Jimin Wang, Jinchan Liu, David A. Flesher, Krystle M. Reiss, Hao-Li Huang, Ke R. Yang, William H. Armstrong, M. R. Gunner, Victor S. Batista, Richard J. Debus, Gary W. Brudvig

Publications and Research

Photosystem II (PSII) enables global-scale, light-driven water oxidation. Genetic manipulation of PSII from the mesophilic cyanobacterium Synechocystis sp. PCC 6803 has provided insights into the mechanism of water oxidation; however, the lack of a highresolution structure of oxygen-evolving PSII from this organism has limited the interpretation of biophysical data to models based on structures of thermophilic cyanobacterial PSII. Here, we report the cryo-electron microscopy structure of PSII from Synechocystis sp. PCC 6803 at 1.93-Å resolution. A number of differences are observed relative to thermophilic PSII structures, including the following: the extrinsic subunit PsbQ is maintained, the C terminus of the …

Cryptococcus Neoformans Melanization Incorporates Multiple Catecholamines To Produce Polytypic Melanin, Rosanna P. Baker, Christine Chrissian, Ruth E. Stark, Arturo Casadevall

Publications and Research

Melanin is a major virulence factor in pathogenic fungi that enhances the ability of fungal cells to resist immune clearance. Cryptococcus neoformans is an important human pathogenic fungus that synthesizes melanin from exogenous tissue catecholamine precursors during infection, but the type of melanin made in cryptococcal meningoencephalitis is unknown. We analyzed the efficacy of various catecholamines found in brain tissue in supporting melanization using animal brain tissue and synthetic catecholamine mixtures reflecting brain tissue proportions. Solid-state NMR spectra of the melanin pigment produced from such mixtures yielded more melanin than expected if only the preferred constituent dopamine had been incorporated, …

A Pkcα-Mediated Growth Suppressive Mek-Erk Signaling Axis In Intestinal Epithelial Cells, Navneet Kaur

Theses & Dissertations

Members of the protein kinase C (PKC) family of serine/threonine kinases are involved in regulation of fundamental cellular functions, including proliferation, differentiation, survival, migration, and transformation. Increasing evidence points to anti-proliferative and tumor suppressive role of PKCs. Our laboratory and others have reported that the classical PKC isozyme, PKCαnegatively regulates proliferation and tumorigenesis in the intestinal epithelium. Our laboratory has further determined that PKCα signaling induces a program of cell cycle withdrawal in intestinal epithelial cells that involves downregulation of the pro-proliferative proteins, cyclin D1 and Id1, and upregulation of the cyclin dependent kinase (CDK) inhibitor, p21^Cip1. Unexpectedly, …

Molecular Mechanisms Of Aberrant Protein Glycosylation In Pancreatic Cancer Stemness And Metastasis, Frank Leon

Theses & Dissertations

A myriad of genetic and other abnormal changes underlies the aggressiveness and dissemination properties observed in pancreatic cancer (PC). Aberrant protein glycosylation is a commonly observed feature in PC. The modification of protein O-glycosylation is mediated by glycosyltransferases, which attach and sequentially elongate monosaccharides on Serine/Threonine (Ser/Thr) motifs. Aberrant glycosylation is recognized as an emerging hallmark of cancer where a disruption in normal glycosylation results in irregular O-glycans.

This dissertation research has investigated the consequences of aberrant protein glycosylation on stemness and enhancement of metastatic properties in pancreatic ductal adenocarcinoma (PDAC). Several publications have reported aberrant O-glycosylation increases in oncogenic …

A Review Of Calcineurin Biophysics With Implications For Cardiac Physiology, Ryan B. Williams

Theses and Dissertations

Calmodulin is a prevalent calcium sensing protein found in all cells. Three genes exist for calmodulin and all three of these genes encode for the exact same protein sequence. Recently mutations in the amino acid sequence of calmodulin have been identified in living human patients. Thus far, patients harboring these mutations in the calmodulin sequence have only displayed an altered cardiac related phenotype. Calcineurin is involved in many key physiological processes and its activity is regulated by calcium and calmodulin. In order to assess whether or not calcineurin contributes to calmodulinopathy (a pathological state arising from dysfunctional calmodulin), a comprehensive …

Granulins In Norm And Neurodegenerative Pathologies, Anukool Bhopatkar

Dissertations

Granulins (GRNs) are small, cysteine-rich modules produced from the proteolytic cleavage of the precursor protein called progranulin (PGRN). GRNs are present in the form of seven tandem repeats within the precursor and are known to be produced in the extracellular and in lysosomal environments. In physiology, PGRN and GRNs plays pleiotropic roles such as neuronal growth and differentiation, immunomodulation, wound healing. Recent studies have implicated pathological role for PGRN in Alzheimer disease (AD) and frontotemporal dementia (FTD) but specific mechanism(s) remains unclear. However, potential interactions between GRNs and Ab42 and TDP-43 seem like a plausible underlying mechanism. Studies presented here …

Elucidation Of The Cellular Mechanisms Underlying Missense Mutations In Low Density Lipoprotein Receptor Related Protein 6 (Lrp6) Associated With Cardiovascular Diseases, Huda Issa Samha

Theses

Low-density Lipoprotein Receptor Related Protein 6 (LRP6) is a member of the Low-Density Lipoprotein Receptors family (LDLRs) which is involved in the clearance of LDL from the bloodstream and the signaling of the canonical wingless signaling pathway. Several genetic variants in the LRP6 gene have been conclusively associated with cardiovascular diseases (CVDs) and metabolic syndrome. However, the structural and functional implications of those variations have not been fully elucidated. The CVD-associated LRP6 variants could be retained and possibly subjected to Endoplasmic Reticulum Associated Degradation (ERAD), a quality control and adaptive process employed by cells to eliminate misfolded proteins to maintain …