Biochemistry Commons^™

Oxidative Stress, Metabolomics Profiling, And Mechanism Of Local Anesthetic Induced Cell Death In Yeast, Cory Honsinger Thomas Boone, Ryan A. Grove, Dana Adamcova, Javier Seravalli, Jiri Adamec

Department of Biochemistry: Faculty Publications

The World Health Organization designates lidocaine as an essential medicine in healthcare, greatly increasing the probability of human exposure. Its use has been associated with ROS generation and neurotoxicity. Physiological and metabolomic alterations, and genetics leading to the clinically observed adverse effects have not been temporally characterized. To study alterations that may lead to these undesirable effects, Saccharomyces cerevisiae grown on aerobic carbon sources to stationary phase was assessed over 6 h. Exposure of an LC₅₀ dose of lidocaine, increased mitochondrial depolarization and ROS/RNS generation assessed using JC-1, ROS/RNS specific probes, and FACS. Intracellular calcium also increased, assessed by …

Toxoplasma Dj-1 Regulates Organelle Secretion By A Direct Interaction With Calcium-Dependent Protein Kinase 1, Matthew A. Child, Megan Garland, Ian Foe, Peter Madzelan, Moritz Treeck, Wouter A. Van Der Linden, Kristina Oresic Bender, Evanthie Weerapana, Mark A. Wilson, John C. Boothroyd, Michael L. Reese

Department of Biochemistry: Faculty Publications

Human DJ-1 is a highly conserved and yet functionally enigmatic protein associated with a heritable form of Parkinson’s disease. It has been suggested to be a redox-dependent regulatory scaffold, binding to proteins to modulate their function. Here we present the X-ray crystal structure of the Toxoplasma orthologue Toxoplasma gondii DJ-1 (TgDJ-1) at 2.1-A resolution and show that it directly associates with calcium-dependent protein kinase 1 (CDPK1). The TgDJ-1 structure identifies an orthologously conserved arginine dyad that acts as a phospho-gatekeeper motif to control complex formation. We determined that the binding of TgDJ-1 to CDPK1 is sensitive to oxidation and calcium, …

Seasonal Switchgrass Ecotype Contributions To Soil Organic Carbon, Deep Soil Microbial Community Composition And Rhizodeposit Uptake During An Extreme Drought, Catherine E. Stewart, Damaris Roosendaal, Karolien Denef, Elizabeth Pruessner, Louise H. Comas, Gautam Sarath, Virginia L. Jin, Marty R. Schmer, Madhavan Soundararajan

Department of Biochemistry: Faculty Publications

The importance of rhizodeposit C and associated microbial communities in deep soil C stabilization is relatively unknown. Phenotypic variability in plant root biomass could impact C cycling through belowground plant allocation, rooting architecture, and microbial community abundance and composition. We used a pulse-chase ¹³C labeling experiment with compound-specific stable-isotope probing to investigate the importance of rhizodeposit C to deep soil microbial biomass under two switchgrass ecotypes (Panicum virgatum L., Kanlow and Summer) with contrasting root morphology. We quantified root phenology, soil microbial biomass (phospholipid fatty acids, PLFA), and microbial rhizodeposit uptake (¹³C-PLFAs) to 150 cm over …

Secs (Sinusoidal Endothelial Cells), Liver Microenvironment, And Fibrosis, Vaishaali Natarajan, Edward N. Harris, Srivatsan Kidambi

Department of Biochemistry: Faculty Publications

Liver fibrosis is awound-healing response to chronic liver injury such as alcoholic/nonalcoholic fatty liver disease and viral hepatitis with no FDA-approved treatments. Liver fibrosis results in a continual accumulation of extracellular matrix (ECM) proteins and paves the way for replacement of parenchyma with nonfunctional scar tissue. The fibrotic condition results in drastic changes in the local mechanical, chemical, and biological microenvironment of the tissue. Liver parenchyma is supported by an efficient network of vasculature lined by liver sinusoidal endothelial cells (LSECs). These nonparenchymal cells are highly specialized resident endothelial cell type with characteristic morphological and functional features. Alterations in LSECs …

Gene Duplication And Neo-Functionalization In The Evolutionary And Functional Divergence Of The Metazoan Copper Transporters Ctr1 And Ctr2, Brandon L. Logeman, L. Kent Wood, Jaekwoon Lee, Dennis J. Thiele

Department of Biochemistry: Faculty Publications

Copper is an essential element for proper organismal development and is involved in a range of processes, including oxidative phosphorylation, neuropeptide biogenesis, and connective tissue maturation. The copper transporter (Ctr) family of integral membrane proteins is ubiquitously found in eukaryotes and mediates the high-affinity transport of Cu_ across both the plasma membrane and endomembranes. Although mammalian Ctr¹ functions as a Cu_ transporter for Cu acquisition and is essential for embryonic development, a homologous protein, Ctr², has been proposed to function as a low-affinity Cu transporter, a lysosomal Cu exporter, or a regulator of Ctr¹ activity, but …

Carbon And Acyl Chain Flux During Stress-Induced Triglyceride Accumulation By Stable Isotopic Labeling Of The Polar Microalga Coccomyxa Subellipsoidea C169, James W. Allen, Concetta C. Dirusso, Paul N. Black

Department of Biochemistry: Faculty Publications

Deriving biofuels and other lipoid products from algae is a promising future technology directly addressing global issues of atmospheric CO₂ balance. To better understand the metabolism of triglyceride synthesis in algae, we examined their metabolic origins in the model species, Coccomyxa subellipsoidea C169, using stable isotopic labeling. Labeling patterns arising from [U-¹³C]glucose, ¹³CO₂, or D₂O supplementation were analyzed by GC-MS and/or LC-MS over time courses during nitrogen starvation to address the roles of catabolic carbon recycling, acyl chain redistribution, and de novo fatty acid (FA) synthesis during the expansion of the lipid …

Quantification Of Cell Signaling Networks Using Kinase Activity Chemosensors, Jon R. Beck, Edward N. Harris, Cliff I. Stains

Department of Biochemistry: Faculty Publications

The ability to directly determine endogenous kinase activity in tissue homogenates provides valuable insights into signaling aberrations that underlie disease phenotypes. When activity data is collected across a panel of kinases, a unique “signaling fingerprint” is generated that allows for discrimination between diseased and normal tissue. Here we describe the use of peptide-based kinase activity sensors to fingerprint the signaling changes associated with disease states. This approach leverages the phosphorylation-sensitive sulfonamido-oxine (Sox) fluorophore to provide a direct readout of kinase enzymatic activity in unfractionated tissue homogenates from animal models or clinical samples. To demonstrate the application of this technology, we …

The Intestinal Copper Exporter Cua-1 Is Required For Systemic Copper Homeostasis In Caenorhabditis Elegans, Haarin Chun, Anuj Kumar Sharma, Jaekwon Lee, Jefferson Chan, Shang Jia, Byung-Eun Kim

Department of Biochemistry: Faculty Publications

Copper plays key catalytic and regulatory roles in biochemical processes essential for normal growth, development, and health. Defects in copper metabolism cause Menkes and Wilson’s disease, myeloneuropathy, and cardiovascular disease and are associated with other pathophysiological states. Consequently, it is critical to understand the mechanisms by which organisms control the acquisition, distribution, and utilization of copper. The intestinal enterocyte is a key regulatory point for copper absorption into the body; however, the mechanisms by which intestinal cells transport copper to maintain organismal copper homeostasis are poorly understood. Here, we identify a mechanism by which organismal copper homeostasis is maintained by …

Structural Determinants Allowing Transferase Activity In Sensitive To Freezing 2, Classified As A Family I Glycosyl Hydrolase, Rebecca Roston, Kun Wang, Leslie A. Kuhn, Christoph Benning

Department of Biochemistry: Faculty Publications

Background: SENSITIVE TO FREEZING 2 (SFR2) is classified as a glycosyl hydrolase, and by using glycosyltransferase activity, it modifies membrane lipids to promote freeze tolerance.

Results: Although the active site of SFR2 is identical to hydrolases, adjacent loop regions contribute to its transferase activity.

Conclusion: Transferase activity evolved by modifications external to the core catalytic site.

Significance: Defined structure-function relationships will inform engineering of transferases and freeze tolerance.

Sending Out An Sos: Mitochondria As A Signaling Hub, Iryna Bohovych, Oleh Khalimonchuk

Department of Biochemistry: Faculty Publications

Normal cellular physiology is critically dependent on numerous mitochondrial activities including energy conversion, cofactor and precursor metabolite synthesis, and regulation of ion and redox homeostasis. Advances in mitochondrial research during the last two decades provide solid evidence that these organelles are deeply integrated with the rest of the cell and multiple mechanisms are in place to monitor and communicate functional states of mitochondria. In many cases, however, the exact molecular nature of various mitochondria-to-cell communication pathways is only beginning to emerge. Here, we review various signals emitted by distressed or dysfunctional mitochondria and the stress-responsive pathways activated in response to …

Loss Of Exogenous Androgen Dependence By Prostate Tumor Cells Is Associated With Elevated Glucuronidation Potential, Brenna M. Zimmer, Michelle E. Howell, Qin Wei, Linlin Ma, Trevor Romsdahl, Eileen G. Loughman, Jennifer E. Markham, Javier Seravalli, Joseph J. Barycki, Melanie A. Simpson

Department of Biochemistry: Faculty Publications

Prostate epithelial cells control the potency and availability of androgen hormones in part by inactivation and elimination. UDP-glucose dehydrogenase (UGDH) catalyzes the NAD⁺-dependent oxidation of UDP-glucose to UDP-glucuronate, an essential precursor for androgen inactivation by the prostate glucuronidation enzymes UGT2B15 and UGT2B17. UGDH expression is androgen stimulated, which increases the production of UDP-glucuronate, and fuels UGT-catalyzed glucuronidation. In this study, we compared the glucuronidation potential and its impact on androgen-mediated gene expression in an isogenic LNCaP model for androgen dependent versus castration resistant prostate cancer. Despite significantly lower androgen-glucuronide output, LNCaP 81 castration resistant tumor cells expressed higher …

Small-Angle X-Ray Scattering Studies Of The Oligomeric State And Quaternary Structure Of The Trifunctional Proline Utilization A (Puta) Flavoprotein From Escherichia Coli, Ranjan K. Singh, John D. Larson, Weidong Zhu, Robert P. Rambo, Greg L. Hura, Donald F. Becker, John J. Tanner

Department of Biochemistry: Faculty Publications

Background: Trifunctional proline utilization A (PutA) proteins are multifunctional flavoproteins that catalyze two reactions and repress transcription of the put regulon.

Results: PutA from Escherichia coli is a V-shaped dimer, with the DNA-binding domain mediating dimerization.

Conclusion: Oligomeric state and quaternary structures are not conserved by PutAs.

Significance: The first three-dimensional structural information for any trifunctional PutA is reported.

Binding Of Oxygen To Human Hemoglobin Within The Erythrocyte Using Icam Spectrophotometry, Kyle K. Hill

Department of Chemistry: Dissertations, Theses, and Student Research

Many of the spectrophotometric techniques used to determine the properties of intracellular human hemoglobin cannot be utilized due to the turbidity of erythrocyte suspensions. An Integrating Cavity Absorption Meter, or ICAM, allows for absorption measurements of strongly scattering samples in the visible-light region of the spectrum. The spectrum of oxygenated hemoglobin within erythrocytes is significantly different from the absorption spectrum of oxygenated hemoglobin in solution. Studies of the oxygen binding to hemoglobin in erythrocytes allowed the four sequential binding constants (Adair constants) to be determined and compared with those of hemoglobin in solution. The Adair constants for hemoglobin in solution …

Stabilin-Mediated Cellular Internalization Of Phosphorothioate-Modified Antisense Oligonucleotides (Asos), Colton M. Miller, Aaron J. Donner, Emma K. Blank, Andrew W. Egger, Brianna M. Kellar, Punit P. Seth, Edward N. Harris

UCARE: Research Products

Introduction: Antisense oligonucleotides (ASOs) are short chemically modified oligonucleotides (5-7.4 kDa) that can produce a pharmacological effect by binding to RNA and affecting intermediary metabolism. Over 35 phosphorothioate (PS) ASOs are at various stages of clinical development for use as therapeutic agents and pharmacological tools. Antisense therapy is a progressing area of research, as these small strands of nucleotide oligomers can be produced to silence genes that aggravate chronic disorders or infections. An important distinction for ASOs compared to DNA is the substitution of the phosphodiester (PO) backbone with the PS modification. This sulfur substitution allows for these polar polyanionic …

Mutant Study Of Sinorhizobium Meliloti Proline Utilization A (Puta), Jacob E. Wilkinson, John J. Tanner, Donald F. Becker

UCARE: Research Products

The purpose of this project is to purify and characterize the reaction kinetics of mutant versions the enzyme Proline Utilization A (PutA) in Sinorhizobium meliloti. The enzyme catalyzes the first step in proline metabolism. It has two active sites. The first is proline dehydrogenase (PRODH) which converts proline to pyrroline-5-carboxylate (P5C). The second is P5C dehydrogenase (P5CDH) which converts P5C to glutamate. Although many bacterial organisms have PutA, there are still significant interspecies variations, resulting in an entire family of PutA enzymes. The main difference is the length of the amino acid sequence. This affects the protein’s structure or …

The Nmr Solution Structure And Function Of Rpa3313: A Hypothetical Protein From R. Palustris, Austin J. Lowe, Jonathan Catazaro, Cheryl Arrowsmith, Robert Powers

UCARE: Research Products

Protein function elucidation often relies heavily on amino acid sequence analysis and other bioinformatics approaches. The reliance is further extended to structure homology modeling for ligand docking and protein-protein interaction mapping. However, sequence analysis of RPA3313 exposes a large, unannotated class of hypothetical proteins mostly from the Rhizobiales order. In the absence of sequence and structure information, further functional elucidation of this class of proteins has been significantly hindered. A high quality NMR structure of RPA3313 reveals that the protein forms a novel split βαβ fold with a conserved ligand binding pocket between the first β-strand and the N-terminus of …

Genetically Incorporated Vinyl Sulfide For Various Bioorthogonal Reactions, Carly Faller, Xin Shang, Jiantao Guo

UCARE: Research Products

No abstract provided.

Analysis Of Histone Deacetylase Involvement In Pseudomonas Syringae-Triggered Chromatin Changes, Jennifer Wies, Victoria Shum, Karin V. Van Dijk

UCARE: Research Products

I had the great privilege of working with Dr. Karin van Dijk, through UCARE, researching the specific pathways through which histone deacetylation occurs in plants during the 2015-2016 academic year. My first year conducting research helped me develop my technical skills and learn about experimental protocols and how to conduct them. I would like to continue my research during the 2016-2017 academic year and now that I have a year of research experience, be able to further develop my skills and learn more about my research project.

Background

Pseudomonas syringae is a bacterial pathogen that is well known for causing …

Hair Analysis In Motor Vehicles, Jaclyn E. Humrich, Larry Barksdale

UCARE: Research Products

The purpose of this research was to examine the frequency of human and animal hair in motor vehicles in the Lincoln, NE area. We were looking specifically at animal hair to see if there is a significant difference in the distribution of animal hair in pet-owner and non pet-owner vehicles. Finding a significantly high distribution of animal hair in pet-owner vehicles would lead us to believe that an association could be made between a suspect owning an animal and their presence at a crime scene.

Our null hypothesis is that there is no significance in the distribution of cat/dog hairs …

Defining The Roles Of Serine Palmitoyltransferase-Interacting Proteins In The Regulation Of Sphingolipid Homeostasis, Athen N. Kimberlin

Department of Biochemistry: Dissertations, Theses, and Student Research

Sphingolipids are major structural components of the plasma membrane and endomembrane system. Research suggests that sphingolipids are involved with the formation of lipid microdomains, also known as lipid rafts, which may help to organize proteins within the membrane and may be important for membrane trafficking. Aside from their structural roles in membranes, sphingolipids and their metabolic products have been implicated in several cellular signaling responses like programmed cell death (PCD). Because of this, maintenance of sphingolipid homeostasis is critical for eukaryotic cell growth and development. Serine palmitoyltransferase (SPT) catalyzes the first step in sphingolipid biosynthesis and is the primary regulatory …

Methods For Detecting Microbial Methane Production And Consumption By Gas Chromatography, Jared T. Aldridge, Jennie L. Catlett, Megan L. Smith, Nicole R. Buan

Department of Biochemistry: Faculty Publications

Methane is an energy-dense fuel but is also a greenhouse gas 25 times more detrimental to the environment than CO2. Methane can be produced abiotically by serpentinization, chemically by Sabatier or Fisher-Tropsh chemistry, or biotically by microbes (Berndt et al., 1996; Horita and Berndt, 1999; Dry, 2002; Wolfe, 1982; Thauer, 1998; Metcalf et al., 2002). Methanogens are anaerobic archaea that grow by producing methane gas as a metabolic byproduct (Wolfe, 1982; Thauer, 1998). Our lab has developed and optimized three different gas chromatograph-utilizing assays to characterize methanogen metabolism (Catlett et al., 2015). Here we describe the end point and kinetic …

Stabilin-1 And Stabilin-2 Are Specific Receptors For The Cellular Internalization Of Phosphorothioate-Modified Antisense Oligonucleotides (Asos) In The Liver, Colton M. Miller, Aaron J. Donnerr, Emma E. Blank, Andrew W. Egger, Brianna M. Kellar, Michael E. Østergaard, Punit P. Seth, Edward N. Harris

Department of Biochemistry: Faculty Publications

Phosphorothioate (PS)-modified antisense oligonucleotides (ASOs) have been extensively investigated over the past three decades as pharmacological and therapeutic agents. One second generation ASO, Kynamro^TM, was recently approved by the FDA for the treatment of homozygous familial hypercholesterolemia and over 35 second generation PS ASOs are at various stages of clinical development. In this report, we show that the Stabilin class of scavenger receptors, which were not previously thought to bind DNA, do bind and internalize PS ASOs. With the use of primary cells from mouse and rat livers and recombinant cell lines each expressing Stabilin-1 and each isoform …

Nitrogenase Femoco Investigated By Spatially Resolved Anomalous Dispersion Refinement, Thomas Spatzal, Julia Schlesier, Eva-Maria Burger, Daniel Sippel, Limei Zhang, Susana L.A. Andrade, Douglas C. Rees, Oliver Einsle

Department of Biochemistry: Faculty Publications

The [Mo:7Fe:9S:C] iron-molybdenum cofactor (FeMoco) of nitrogenase is the largest known metal cluster and catalyses the 6-electron reduction of dinitrogen to ammonium in biological nitrogen fixation. Only recently its atomic structure was clarified, while its reactivity and electronic structure remain under debate. Here we show that for its resting S 1⁄4 3/2 state the common iron oxidation state assignments must be reconsidered. By a spatially resolved refinement of the anomalous scattering contributions of the 7 Fe atoms of FeMoco, we conclude that three irons (Fe1/3/7) are more reduced than the other four (Fe2/4/5/6). Our data are in agreement with the …

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 …