Biochemistry, Biophysics, and Structural Biology Commons^™

Functional Effects Of Calcium Regulation Of Thin Filaments At Single Particle Resolution, Christopher Solis-Ocampo

Electronic Theses and Dissertations

Heart disease is the leading cause of death in the United States. Understanding heart function at the molecular level is critical for developing of more effective treatments. In the cardiac muscle, the thin filament is composed by troponin (Tn), tropomyosin (Tm), and F-actin. It provides Ca2+-dependent regulation of contraction by modulating myosin attachment and force generation in a cooperative scheme. However, this mechanism remains unclear. To understand thin filament activation, we studied the binding and functional properties of Tn and Tm to F-actin at single particle resolution by employing fluorescence image colocalization, in vitro motility assays, and Förster resonance energy …

A Dielectric Rod Antenna For Picosecond Pulse Stimulation Of Neurological Tissue, Ross A. Petrella, Karl H. Schoenbach, Shu Xiao

Bioelectrics Publications

A dielectrically loaded wideband rod antenna has been studied as a pulse delivery system to subcutaneous tissues. Simulation results applying 100-ps electrical pulse show that it allows us to generate a critical electric field for biological effects, such as brain stimulation, in the range of several centimeters. In order to reach the critical electric field for biological effects, which is similar to 20 kV/cm, at a depth of 2 cm, the input voltage needs to be 175 kV. The electric field spot size in the brain at this position is similar to 1 cm(2). Experimental studies in free space with …

Large Genomic Differences Between Moraxella Bovoculi Isolates Acquired From The Eyes Of Cattle With Infectious Bovine Keratoconjunctivitis Versus The Deep Nasopharynx Of Asymptomatic Cattle, Aaron M. Dickey, John D. Loy, James L. Bono, Timonthy P. L. Smith, Mike D. Apley, Brian V. Lubbers, Keith D. Dedonder, Sarah F. Capik, Robert L. Larson, Brad J. White, Jochen Blom, Carol G. Chitko-Mckown, Michael L. Clawson

School of Veterinary and Biomedical Sciences: Faculty Publications

Moraxella bovoculi is a recently described bacterium that is associated with infectious bovine keratoconjunctivitis (IBK) or “pinkeye” in cattle. In this study, closed circularized genomes were generated for seven M. bovoculi isolates: three that originated from the eyes of clinical IBK bovine cases and four from the deep nasopharynx of asymptomatic cattle. Isolates that originated from the eyes of IBK cases profoundly differed from those that originated from the nasopharynx of asymptomatic cattle in genome structure, gene content and polymorphism diversity and consequently placed into two distinct phylogenetic groups. These results suggest that there are genetically distinct strains of M. …

Role Of Apoptotic Hepatocytes In Hcv Dissemination: Regulation By Acetaldehyde, Murali Ganesan, Sathish Kumar Natarajan, Jinjin Zhang, Justin L. Mott, Larisa I. Poluektova, Benita L. Mcvicker, Kusum K. Kharbanda, Dean J. Tuma, Natalie A. Osna

Department of Biochemistry: Faculty Publications

Alcohol consumption exacerbates hepatitis C virus (HCV) pathogenesis and promotes disease progression, although the mechanisms are not quite clear. We have previously observed that acetaldehyde (Ach) continuously produced by the acetaldehyde-generating system (AGS), temporarily enhanced HCV RNA levels, followed by a decrease to normal or lower levels, which corresponded to apoptosis induction. Here, we studied whether Ach-induced apoptosis caused depletion of HCV-infected cells and what role apoptotic bodies (AB) play in HCV-alcohol crosstalk. In liver cells exposed to AGS, we observed the induction of miR-122 and miR-34a. As miR-34a has been associated with apoptotic signaling and miR-122 with HCV replication, …

Inhibition Of Protein Ubiquitination By Paraquat And 1-Methyl-4-Phenylpyridinium Impairs Ubiquitin-Dependent Protein Degradation Pathways, Juliana Navarro-Yepes, Anandhan Annadurai, Erin Bradley, Iryna Bohovych, Bo Yarabe, Annemieke De Jong, Huib Ovaa, You Zhou, Oleh Khalimonchuk, Betzabet Quintanilla-Vega, Rodrigo Franco

Department of Biochemistry: Faculty Publications

Intracytoplasmic inclusions of protein aggregates in dopaminergic cells (Lewy bodies) are the pathological hallmark of Parkinson’s disease (PD). Ubiquitin (Ub), alpha [α]-synuclein, p62/sequestosome 1 and oxidized proteins are major components of Lewy bodies. However, the mechanisms involved in the impairment of misfolded/oxidized protein degradation pathways in PD are still unclear. PD is linked to mitochondrial dysfunction and environmental pesticide exposure. In this work, we evaluated the effect of the pesticide paraquat (PQ) and the mitochondrial toxin 1-methyl-4-phenylpyridinium (MPP⁺) on Ub-dependent protein degradation pathways. No increase in the accumulation of Ub-bound proteins or aggregates was observed in dopaminergic cells …

Tumor Suppressive Role Of Sestrin2 During Colitis And Colon Carcinogenesis, Seung-Hyun Ro, Xiang Xue, Sadeesh K. Ramakrishnan, Chun-Seok Cho, Sim Namkoong, Insook Jang, Ian A. Semple, Allison Ho, Hwan-Woo Park, Yatrik M. Shah, Jun Hee Lee

Department of Biochemistry: Faculty Publications

The mTOR complex 1 (mTORC1) and endoplasmic reticulum (ER) stress pathways are critical regulators of intestinal inflammation and colon cancer growth. Sestrins are stress-inducible proteins, which suppress both mTORC1 and ER stress; however, the role of Sestrins in colon physiology and tumorigenesis has been elusive due to the lack of studies in human tissues or in appropriate animal models. In this study, we show that human SESN2 expression is elevated in the colon of ulcerative colitis patients but is lost upon p53 inactivation during colon carcinogenesis. In mouse colon, Sestrin2 was critical for limiting ER stress and promoting the recovery …

Potassium And The K+/H+ Exchanger Kha1p Promote Binding Of Copper To Apofet3p Multi-Copper Ferroxidase, Xiaobin Wu, Heejeong Kim, Javier Seravalli, Joseph J. Barycki, P. John Hart, David W. Gohara, Enrico Di Cera, Won Hee Jung, Daniel J. Kosman, Jaekwon Lee

Department of Biochemistry: Faculty Publications

Acquisition and distribution of metal ions support a number of biological processes. Here we show that respiratory growth of and iron acquisition by the yeast Saccharomyces cerevisiae relies on potassium (K⁺) compartmentalization to the trans-Golgi network via Kha1p, a K⁺/H⁺ exchanger. K⁺ in the trans-Golgi network facilitates binding of copper to the Fet3p multi-copper ferroxidase. The effect of K⁺ is not dependent on stable binding with Fet3p or alteration of the characteristics of the secretory pathway. The data suggest that K⁺ acts as a chemical factor in Fet3p maturation, a …

Analysis Of Oligomerization Properties Of Heme A Synthase Provides Insights Into Its Function In Eukaryotes, Samantha Swenson, Andrew Cannon, Nicholas J. Harris, Nicholas G. Taylor, Jennifer L. Fox, Oleh Khalimonchuk

Department of Biochemistry: Faculty Publications

Heme a is an essential cofactor for function of cytochrome c oxidase in the mitochondrial electron transport chain. Several evolutionarily conserved enzymes have been implicated in the biosynthesis of heme a, including the heme a synthase Cox15. However, the structure of Cox15 is unknown, its enzymatic mechanism and the role of active site residues remain debated, and recent discoveries suggest additional chaperone-like roles for this enzyme. Here, we investigated Cox15 in the model eukaryote Saccharomyces cerevisiae via several approaches to examine its oligomeric states and determine the effects of active site and human pathogenic mutations. Our results indicate that Cox15 …

Development Of A Chemical Genetic Screen To Determine Synergistic Compounds With Laromustine In Treating Glioblastoma Multiforme Cultured Cells, Ryan Weeks

Honors Theses

Laromustine is a chemotherapeutic sulfonylhydrazine prodrug used in clinical trials to treat acute myeloid leukemia (AML) and glioblastoma multiforme (GBM). While treatment of AML with laromustine has more demonstrative clinical success, there are enough promising data against GBM to pursue additional pre-clinical and clinical experiments. To determine the synergistic effects caused by treating cultured GBM cells with laromustine and a library of FDA-approved compounds, a chemical genetic screen was developed. To optimize the screen, optimal cultured GBM cell seed density, growth period and maximum well capacity were determined. The treatment period for a lethal dose of laromustine in cultured GBM …

White-Rot Fungi As Pretreatment Agents For Wood Destined For Biofuel Applications, Ryan M. Kalinoski

Masters Theses

Efficient and economical conversion of lignocellulosic biomass to biofuels is often hampered by the chemical recalcitrance of the material. Inexpensive and environmentally-friendly pretreatment processes are therefore desirable in order to lower the cost of biofuel production and minimize negative environmental impacts. To that end, we have explored the use of a naturally occurring white-rot fungus, Trametes versicolor, as a direct pretreatment agent for hardwood destined for biofuel applications. Specifically, we examined the pretreatment effects on the hardwood mixture after treatment with the wild-type strain of T. versicolor (52J) compared with those from a cellobiose dehydrogenase (CDH)-deficient strain (m4D) , …

Investigation Of Anaplasma Phagocytophilum And Anaplasma Marginale Adhesin-Host Cell Interactions, Kathryn S. Hebert

Theses and Dissertations

Anaplasma phagocytophilum and A. marginale are the etiologic agents of bovine anaplasmosis and human granulocytic anaplasmosis, respectively. As obligate intracellular pathogens, binding and entry of host cells is a prerequisite for survival. The molecular events associated with these processes are poorly understood. Identifying the adhesins mediating binding, delineating their key functional domains, and determining the molecular determinants to which they bind not only benefits better understanding of Anaplasma spp. pathobiology, but could also benefit the development of novel approaches for protecting against infection. We previously demonstrated that A. phagocytophilum outer membrane protein A (ApOmpA) is critical for bacterial binding and …

Conserved Intramolecular Interactions Maintain Myosin Interacting-Heads Motifs Explaining Tarantula Muscle Super-Relaxed State Structural Basis, Lorenzo Alamo, Dan Qi, Willy Wriggers, Antonio Pinto, Jingui Zhu, Aivett Bilbao, Richard E. Gillilan, Songnian Hu, Raúl Padrón

Mechanical & Aerospace Engineering Faculty Publications

Tarantula striated muscle is an outstanding system for understanding the molecular organization of myosin filaments. Three-dimensional reconstruction based on cryo-electron microscopy images and single-particle image processing revealed that, in a relaxed state, myosin molecules undergo intramolecular head head interactions, explaining why head activity switches off. The filament model obtained by rigidly docking a chicken smooth muscle myosin structure to the reconstruction was improved by flexibly fitting an atomic model built by mixing structures from different species to a tilt-corrected 2-nm three-dimensional map of frozen-hydrated tarantula thick filament. We used heavy and light chain sequences from tarantula myosin to build a …

It Is All About (U)Biquitin: Role Of Altered Ubiquitin-Proteasome System And Uchl1 In Alzheimer Disease, Antonella Tramutola, Fabio Di Domenico, Eugenio Barone, Marzia Perluigi, D. Allan Butterfield

Chemistry Faculty Publications

Free radical-mediated damage to macromolecules and the resulting oxidative modification of different cellular components are a common feature of aging, and this process becomes much more pronounced in age-associated pathologies, including Alzheimer disease (AD). In particular, proteins are particularly sensitive to oxidative stress-induced damage and these irreversible modifications lead to the alteration of protein structure and function. In order to maintain cell homeostasis, these oxidized/damaged proteins have to be removed in order to prevent their toxic accumulation. It is generally accepted that the age-related accumulation of “aberrant” proteins results from both the increased occurrence of damage and the decreased efficiency …

The Role Of Arp2/3 In Ring Canal Development In Drosophila Melanogaster, Marina Tipold

Undergraduate Honors Thesis Collection

Infertility and impaired fecundity affect 8.2 million women in the United States. Intercellular bridges are essential to the proper formation of germ cells in many organisms; therefore, learning more about how they are formed and regulated during the formation of sperm and eggs could provide insight into how defects in their structure can impact fertility. Intercellular bridges are actin-rich structures that connect developing germ cells to each other and allow the transfer of materials. I used the development of the fruit fly egg as a model system to study formation and regulation of intercellular bridges. Specifically, I investigated the role …

Alcoholic Vs Non-Alcoholic Fatty Liver In Rats: Distinct Differences In Endocytosis And Vesicle Trafficking Despite Similar Pathology, Karuna Rasineni, Daniel D. Penrice, Sathish Kumar Natarajan, Mark A. Mcniven, Benita L. Mcvicker, Kusum K. Kharbanda, Carol A. Casey, Edward N. Harris

Department of Biochemistry: Faculty Publications

Background: Non-alcoholic and alcoholic fatty liver disease (NAFLD and AFLD, respectively) are major health problems, as patients with either condition can progress to hepatitis, fibrosis, and cirrhosis. Although histologically similar, key differences likely exist in these two models. For example, altered content of several vesicle trafficking proteins have been identified in AFLD, but their content in NAFLD is unknown. In this study, we compared select parameters in NAFLD and AFLD in a rat model.

Methods: We fed either Lieber- DeCarli liquid control or alcohol-containing (35 % as calories) diet (AFLD model) or lean or high-fat (12 or 60 % derived …

Atomic Resolution Experimental Phase Information Reveals Extensive Disorder And Bound 2-Methyl-2,4-Pentanediol In Ca2+-Calmodulin, Jiusheng Lin, Henry Van Den Bedem, Axel T. Brunger, Mark A. Wilson

Department of Biochemistry: Faculty Publications

Calmodulin (CaM) is the primary calcium signaling protein in eukaryotes and has been extensively studied using various biophysical techniques. Prior crystal structures have noted the presence of ambiguous electron density in both hydrophobic binding pockets of Ca²⁺-CaM, but no assignment of these features has been made. In addition, Ca²⁺-CaM samples many conformational substates in the crystal and accurately modeling the full range of this functionally important disorder is challenging. In order to characterize these features in a minimally biased manner, a 1.0 A resolution single-wavelength anomalous diffraction data set was measured for selenomethionine-substituted Ca²⁺-CaM. …

An Evaluation Of New And Established Methods To Determine T-Dna Copy Number And Homozygosity In Transgenic Plants, Katarzyna Glowacka, Johannes Kromdijk, Lauriebeth Leonelli, Krishna K. Niyogi, Tom E. Clemente, Stephen P. Long

Department of Biochemistry: Faculty Publications

Stable transformation of plants is a powerful tool for hypothesis testing.Arapid and reliable evaluation method of the transgenic allele for copy number and homozygosity is vital in analysing these transformations.Here the suitability of Southern blot analysis, thermal asymmetric interlaced (TAIL-)PCR, quantitative (q)PCR and digital droplet (dd)PCR to estimate T-DNA copy number, locus complexity and homozygosity were compared in transgenic tobacco. Southern blot analysis and ddPCR on three generations of transgenic offspring with contrasting zygosity and copy number were entirely consistent, whereas TAIL-PCR often underestimated copy number. qPCR deviated considerably from the Southern blot results and had lower precision and higher …

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 …

Label-Free Quantitative Proteomics Reveals A Novel Sgta/Peroxiredoxin I Complex That Regulates Androgen Receptor Activity, Yenni Alejandra Garcia

Open Access Theses & Dissertations

The dynamic Hsp70-90 chaperone machinery along with its cochaperone partners are well-characterized for their ability to fold, assemble, and regulate steroid hormone receptors (SHRs). Human small glutamine rich tetratricopeptide repeat (TPR) containing protein alpha (SGTA) is a recently identified protein that has a characteristic Hsp90-binding TPR domain and is a key participant in the androgen, glucocorticoid, and progesterone receptor signaling pathway. In addition, SGTA plays a role in cellular processes such as cell cycle progression and apoptosis. We have demonstrated that SGTA binds directly to both Hsp70 (kd = 6 μM) and Hsp90 (kd = 11 μM). In a cell-free …

Study On Dioxygen Binding To Heme Using Scan Functional, Zegnet Yimer Muhammed

Open Access Theses & Dissertations

Density functional theory, a quantum mechanical based electronic structure method with GGA-PBE and MGG-SCAN functionals, are used to investigate the structure and energies of singlet, triplet, and quintet spin states of FeP (iron Porphyrin), FePIm (imidazole iron porphyrin), and FePImO2 (dioxygen imidazole iron porphyrin) systems. The binding and release of dioxygen to and from hemoglobin (Hb) are the most crucial reaction takes place in human body to sustain the existence of life. FePImO2 is used to model this phenomenon. When O2 binds to FePIm, the system undergoes a conformational change. i.e. from domed structure of FePIm in which the Fe …