Biochemistry Commons^™

Defending Your Dna: Combating Threats Both Foreign And Domestic, James Mcisaac

Undergraduate Review

We are under constant assault from forces capable of damaging our DNA. The genetic code of DNA is made up of four nucleotides: adenine (A) which bonds with thymine (T) and guanine (G) which bonds with cytosine (C). If something happens to upset this normal pairing or the nucleotides themselves, our body must spring to action and respond to the damage. When damage to nucleotides prevents the normal replication machinery from doing its job, enzymes like the Y-family polymerases are called in. A special mechanism allows them to identify damage and insert the correct nucleotide or bypass the lesion to …

Studies Of Metabolite–Protein Interactions: A Review, Ryan Matsuda, Cong Bi, Jeanethe Anguizola, Matthew Sobansky, Elliott Rodriguez, John Vargas Badilla, Xiwei Zheng, Benjamin Hage, David S. Hage

David Hage Publications

The study of metabolomics can provide valuable information about biochemical pathways and processes at the molecular level. There have been many reports that have examined the structure, identity and concentrations of metabolites in biological systems. However, the binding of metabolites with proteins is also of growing interest. This review examines past reports that have looked at the binding of various types of metabolites with proteins. An overview of the techniques that have been used to characterize and study metabolite–protein binding is first provided. This is followed by examples of studies that have investigated the binding of hormones, fatty acids, drugs …

Proline Mechanisms Of Stress Survival, Xinwen Liang, Lu Zhang, Sathish Kumar Natarajan, Donald F. Becker

Department of Biochemistry: Faculty Publications

Significance: The imino acid proline is utilized by different organisms to offset cellular imbalances caused by environmental stress. The wide use in nature of proline as a stress adaptor molecule indicates that proline has a fundamental biological role in stress response. Understanding the mechanisms by which proline enhances abiotic/biotic stress response will facilitate agricultural crop research and improve human health. Recent Advances: It is now recognized that proline metabolism propels cellular signaling processes that promote cellular apoptosis or survival. Studies have shown that proline metabolism influences signaling pathways by increasing reactive oxygen species (ROS) formation in the mitochondria …

Acanthamoeba Castellanii Of The T4 Genotype Is A Potential Environmental Host For Enterobacter Aerogenes And Aeromonas Hydrophila, Farzana Abubakar Yousuf, Ruqaiyyah Siddiqui, Naveed Ahmed Khan

Department of Biological & Biomedical Sciences

Background: Acanthamoeba can interact with a wide range of microorganisms such as viruses, algae, yeasts, protists and bacteria including Legionella pneumophila, Pseudomonas aeruginosa, Vibrio cholerae, Helicobacter pylori, Listeria monocytogenes, Mycobacterium spp., and Escherichia coli. In this capacity, Acanthamoeba has been suggested as a vector in the transmission of bacterial pathogens to the susceptible hosts.
Methods: Here, we used a keratitis isolate of A. castellanii of the T4 genotype and studied its interactions with two bacterial genera which have not been tested before, Enterobacter aerogenes, and Aeromonas hydrophila, as well as E. coli. Assays were performed to determine bacterial association with …

Development And Optimization Of The First High Throughput In Vitro Fret Assay To Characterize The Saccharomyces Cerevisiae Gpi-T, Sandamali Amarasingha Ekanayaka

Wayne State University Dissertations

DEVELOPMENT AND OPTIMIZATION OF AN IN VITRO FRET ASSAY TO CHARACTERIZE THE SACCHAROMYCES CEREVISIAE GPI TRANSAMIDASE

By

SANDAMALI AMARASINGHA EKANAYAKA

December 2013

Advisor: Dr. Tamara L. Hendrickson

Major: Biochemistry

Degree: Doctor of Philosophy

The enzyme glycosylphosphatidylinositol transamidase (GPI-T) mediates the attachment of a glycosylphosphatidylinositol (GPI) anchor to the C-terminus of specific proteins to produce GPI anchored proteins. This post-translational modification is essential for viability of eukaryotic organisms. However, very little is known about GPI-T and its catalytic activity. Thus, the research described in this abstract was conducted to develop an in vitro assay to monitor GPI-T. A high-throughput assay for …

Acyl-Lipid Metabolism, Younghua Li-Beisson, Basil Shorrosh, Fred Beisson, Mats X. Andersson, Vincent Arondel, Philip D. Bates, Sébastien Baud, David Bird, Allan Debono, Timothy P. Durrett, Rochus B. Franke, Ian A. Graham, Kenta Katayama, Amélie A. Kelly, Tony Larson, Jonathan E. Markham, Martine Miquel, Isabel Molina, Ikuo Nishida, Owen Rowland, Lacey Samuels, Katherine M. Schmid, Hajime Wada, Ruth Welti, Changcheng Xu, Rémi Zallot, John Ohlrogge

Scholarship and Professional Work - LAS

Acyl lipids in Arabidopsis and all other plants have a myriad of diverse functions. These include providing the core diffusion barrier of the membranes that separates cells and subcellular organelles. This function alone involves more than 10 membrane lipid classes, including the phospholipids, galactolipids, and sphingolipids, and within each class the variations in acyl chain composition expand the number of structures to several hundred possible molecular species. Acyl lipids in the form of triacylglycerol account for 35% of the weight of Arabidopsis seeds and represent their major form of carbon and energy storage. A layer of cutin and cuticular waxes …

Reporters For The Analysis Of N-Glycosylation In Candida Albicans, Shahida Shahana, Hector M. Mora-Montes, Luis Castillo, Iryna Bohovych, Chirag C. Sheth, Frank C. Odds, Neil A.R. Gow, Alistair J.P. Brown

Department of Biochemistry: Faculty Publications

A large proportion of Candida albicans cell surface proteins are decorated post-translationally by glycosylation. Indeed N-glycosylation is critical for cell wall biogenesis in this major fungal pathogen and for its interactions with host cells. A detailed understanding of N-glycosylation will yield deeper insights into host-pathogen interactions. However, the analysis of N-glycosylation is extremely challenging because of the complexity and heterogeneity of these structures. Therefore, in an attempt to reduce this complexity and facilitate the analysis of N-glycosylation, we have developed new synthetic C. albicans reporters that carry a single N-linked glycosylation site derived from Saccharomyces cerevisiae Suc₂. These …

Probing Arabidopsis Chloroplast Diacylglycerol Pools By Selectively Targeting Bacterial Diacylglycerol Kinase To Suborganellar Membranes, Bagyalakshmi Muthan, Rebecca Roston, John E. Froehlich, Christoph Benning

Department of Biochemistry: Faculty Publications

Diacylglycerol (DAG) is an intermediate in metabolism of both triacylglycerols and membrane lipids. Probing the steady-state pools of DAG and understanding how they contribute to the synthesis of different lipids is important when designing plants with altered lipid metabolism. However, traditional methods of assaying DAG pools are difficult, because its abundance is low and because fractionation of subcellular membranes affects DAG pools. To manipulate and probe DAG pools in an in vivo context, we generated multiple stable transgenic lines of Arabidopsis (Arabidopsis thaliana) that target an Escherichia coli DAGkinase (DAGK) to each leaflet of each chloroplast envelope membrane. …

A Comprehensive, Multi-Scale Dynamical Model Of Erbb Receptor Signal Transduction In Human Mammary Epithelial Cells, Tomáš Helikar, Naomi Kochi, Bryan Kowal, Manjari Dimri, Mayumi Naramura, Srikumar M. Raja, Vimla Band, Hamid Band, Jim A. Rogers

Department of Biochemistry: Faculty Publications

The non-receptor tyrosine kinase Src and receptor tyrosine kinase epidermal growth factor receptor (EGFR/ErbB1) have been established as collaborators in cellular signaling and their combined dysregulation plays key roles in human cancers, including breast cancer. In part due to the complexity of the biochemical network associated with the regulation of these proteins as well as their cellular functions, the role of Src in EGFR regulation remains unclear. Herein we present a new comprehensive, multi-scale dynamical model of ErbB receptor signal transduction in human mammary epithelial cells. This model, constructed manually from published biochemical literature, consists of 245 nodes representing proteins …

Sbml Qualitative Models: A Model Representation Format And Infrastructure To Foster Interactions Between Qualitative Modelling Formalisms And Tools, Claudine Chaouiya, Duncan Bérenguier, Sarah M. Keating, Aurélien Naldi, Martijn P. Van Iersel, Nicolas Rodriguez, Andreas Dräger, Finja Büchel, Thomas Cokelaer, Bryan Kowal, Benjamin Wicks, Emanuel Gonçalves, Julien Dorier, Michel Page, Pedro T. Monteiro, Axel Von Kamp, Ioannis Xenarios, Hidde De Jong, Michael Hucka, Steffen Klamt, Denis Thieffry, Nicolas Le Novère, Julio Saez-Rodriguez, Tomáš Helikar

Department of Biochemistry: Faculty Publications

Background: Qualitative frameworks, especially those based on the logical discrete formalism, are increasingly used to model regulatory and signalling networks. A major advantage of these frameworks is that they do not require precise quantitative data, and that they are well-suited for studies of large networks. While numerous groups have developed specific computational tools that provide original methods to analyse qualitative models, a standard format to exchange qualitative models has been missing.

Results: We present the Systems Biology Markup Language (SBML) Qualitative Models Package (“qual”), an extension of the SBML Level 3 standard designed for computer representation of qualitative …

Selenodb 2.0: Annotation Of Selenoprotein Genes In Animals And Their Genetic Diversity In Humans, Frederic Romagne, Didac Santesmasses, Louise White, Gaurab K. Sarangi, Marco Mariotti, Ron Hübler, Antje Weihmann, Genis Parra, Vadim N. Gladyshev, Roderic Guigo, Sergi Castellano

Department of Biochemistry: Faculty Publications

SelenoDB (http://www.selenodb.org) aims to provide high-quality annotations of selenoprotein genes, proteins and SECIS elements. Selenoproteins are proteins that contain the amino acid selenocysteine (Sec) and the first release of the database included annotations for eight species. Since the release of SelenoDB 1.0 many new animal genomes have been sequenced. The annotations of selenoproteins in new genomes usually contain many errors in major databases. For this reason, we have now fully annotated selenoprotein genes in 58 animal genomes. We provide manually curated annotations for human selenoproteins, whereas we use an automatic annotation pipeline to annotate selenoprotein genes in other animal genomes. …

Comparative Metabolic Profiling Of Haberlea Rhodopensis, Thellungiella Halophyla, And Arabidopsis Thaliana Exposed To Low Temperature, Maria Benina, Toshihiro Obata, Nikolay Mehterov, Ivan Ivanov, Veselin Petrov, Valentina Toneva, Alisdair R. Fernie, Tsanko S. Gechev

Department of Biochemistry: Faculty Publications

Haberlea rhodopensis is a resurrection species with extreme resistance to drought stress and desiccation but also with ability to withstand low temperatures and freezing stress. In order to identify biochemical strategies which contribute to Haberlea's remarkable stress tolerance, the metabolic reconfiguration of H. rhodopensis during low temperature (4^◦C) and subsequent return to optimal temperatures (21^◦C) was investigated and compared with that of the stress tolerant Thellungiella halophyla and the stress sensitive Arabidopsis thaliana. Metabolic analysis by GC-MS revealed intrinsic differences in the metabolite levels of the three species even at 21^◦C. H. rhodopensis …

Elucidating Causes Of Diporeia Decline In The Great Lakes Via Metabolomics: Physiological Responses After Exposure To Different Stressors, Suman Maity, Amber Jannasch, Jiri Adamec, James M. Watkins, Thomas Nalepa, Tomas O. Höök, Maria S. Sepúlveda

Department of Biochemistry: Faculty Publications

The benthic macroinvertebrate Diporeia spp. have been extirpated from many areas of the Laurentian Great Lakes, but the mechanisms underlying such declines are not fully understood. Diporeia declines coinciding with the invasion of exotic dreissenid mussels (zebra and quagga) have led to the hypothesis that Diporeia declines are a result of decreased food availability from increasing competition with dreissenids for diatoms. There is additional evidence that Diporeia are negatively affected when in close proximity to dreissenids, probably because of exposure to toxins present in the mussels’ pseudofeces. Diporeia are also known to be sensitive to anthropogenic contaminants (such as polychlorinated …

Microrna Function In Human Diseases, Sathish Kumar Natarajan, Mary Anne Smith, Cody J. Wehrkamp, Ashley M. Mohr, Justin L. Mott

Department of Biochemistry: Faculty Publications

MicroRNAs are emerging as a hot topic in research, and rightfully so. They show great promise as targets of treatment and as markers for common human diseases, such as cancer and metabolic diseases. In this review, we address some of the basic questions regarding micro- RNA function in human disease and the clinical significance of microRNAs. Specifically, micro- RNAs in epigenetics, cancer, and metabolic diseases are discussed, with examples taken from cholangiocarcinoma and nonalcoholic fatty liver disease.

Computational Approaches To Anti-Toxin Therapies And Biomarker Identification, Rebecca Jane Swett

Wayne State University Dissertations

This work describes the fundamental study of two bacterial toxins with computational methods, the rational design of a potent inhibitor using molecular dynamics, as well as the development of two bioinformatic methods for mining genomic data.

Clostridium difficile is an opportunistic bacillus which produces two large glucosylating toxins. These toxins, TcdA and TcdB cause severe intestinal damage. As Clostridium difficile harbors considerable antibiotic resistance, one treatment strategy is to prevent the tissue damage that the toxins cause. The catalytic glucosyltransferase domain of TcdA and TcdB was studied using molecular dynamics in the presence of both a protein-protein binding partner and …

Investigating Therapeutic Options For Lafora Disease Using Structural Biology And Translational Methods, Amanda R. Sherwood

Theses and Dissertations--Molecular and Cellular Biochemistry

Lafora disease (LD) is a rare yet invariably fatal form of epilepsy characterized by progressive degeneration of the central nervous and motor systems and accumulation of insoluble glucans within cells. LD results from mutation of either the phosphatase laforin, an enzyme that dephosphorylates cellular glycogen, or the E3 ubiquitin ligase malin, the binding partner of laforin. Currently, there are no therapeutic options for LD, or reported methods by which the specific activity of glucan phosphatases such as laforin can be easily measured. To facilitate our translational studies, we developed an assay with which the glucan phosphatase activity of laforin as …

Valence-Length Correlations For Chemical Bonds From Atomic Orbital Exponents, F. D. Hardcastle

Journal of the Arkansas Academy of Science

Pauling’s empirical bond valence-length correlation has proven valuable because it offers a quick and convenient way of checking and evaluating molecular structures and determining oxidation states from measured bond lengths. In this study, a simplified quantum-mechanical approach was used to derive Pauling’s empirical bond valence-length relationship by considering overlap of hydrogen-like orbitals. An expression for the b “empirical” fitting parameter was derived in terms of atomic-orbital exponents. A new set of orbital exponents is presented using published atomic/covalent radii and a continuous function for the effective principal quantum. The b parameters calculated from the orbital exponents are consistent with bond …

Synthesis, Characterization, And Properties Of Mononuclear And Dinuclear Ruthenium(Ii) Complexes Containing Phenanthroline And Chlorophenanthroline, Anwar A. Bhuiyan, X. Du

Journal of the Arkansas Academy of Science

The study of photophysical and photochemical properties of ruthenium complexes is of great interest for fundamental practical reasons. Ruthenium complexes have been investigated for use in artificial photosynthesis. This paper deals with the synthesis and spectroscopic investigation of custom-designed ruthenium complexes containing phenanthroline and chloro-phenanthroline ligands. These complexes maybe useful for biological electron-transfer studies. The heteroleptic ruthenium monomer complex Ru(phen)2(Cl-phen) (where phen = 1,10-phenanthroline and Cl-phen=5-chloro-1,10-phenanthroline) was prepared in a two-step procedure previously developed in our laboratory. This monomer complex was used to prepare the ruthenium homometallic dimer complex, (phen)2Ru(phen-phen)Ru(phen)2, by utilizing the Ni-catalyzed coupling reaction. Both complexes were purified …

Primary Pathways Of Intracellular Ca2+ Mobilization By Nanosecond Pulsed Electric Field, Iurii Semenov, Shu Xiao, Andrei G. Pakhomov

Bioelectrics Publications

Permeabilization of cell membranous structures by nanosecond pulsed electric field (nsPEF) triggers transient rise of cytosolic Ca²⁺ concentration ([Ca²⁺]_i), which determines multifarious downstream effects. By using fast ratiometric Ca²⁺ imaging with Fura-2, we quantified the external Ca²⁺ uptake, compared it with Ca²⁺ release from the endoplasmic reticulum (ER), and analyzed the interplay of these processes. We utilized CHO cells which lack voltage-gated Ca²⁺ channels, so that the nsPEF-induced [Ca²⁺]_i changes could be attributed primarily to electroporation. We found that a single 60-ns pulse caused fast [Ca2+]_i increase …

Recruitment Of The Intracellular Ca2+ By Ultrashort Electric Stimuli: The Impact Of Pulse Duration, Iurii Semenov, Shu Xiao, Olga N. Pakhomova, Andrei G. Pakhomov

Bioelectrics Publications

Nanosecond-duration electric stimuli are distinguished by the ability to permeabilize intracellular membranes and recruit Ca²⁺ from intracellular stores. We quantified this effect in non-excitable cells (CHO) using ratiometric Ca²⁺ imaging with Fura-2. In a Ca²⁺-free medium, 10-, 60-, and 300-ns stimuli evoked Ca2⁺ transients by mobilization of Ca²⁺ from the endoplasmic reticulum. With 2 mM external Ca²⁺, the transients included both extra- and intracellular components. The recruitment of intracellular Ca²⁺ increased as the stimulus duration decreased. At the threshold of 200–300 nM, the transients were amplified by calcium-induced calcium release. We …