Open Access. Powered by Scholars. Published by Universities.®

Medicine and Health Sciences Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 15 of 15

Full-Text Articles in Medicine and Health Sciences

Cloning And Expression Of Toxoplasma Gondii Dense Granular Protein 4 (Gra4) In Pichia Pastoris, Init Ithoi Dec 2010

Cloning And Expression Of Toxoplasma Gondii Dense Granular Protein 4 (Gra4) In Pichia Pastoris, Init Ithoi

Init Ithoi

GRA4 of Toxoplasma gondii has been shown to prompt IgG, IgM and IgA responses in previous studies and is thus considered one of the major immunogenic proteins from T. gondii that can be used for both diagnostics purposes and vaccine development. This study seeks to clone and express the GRA4 in Pichia pastoris, which has numerous advantages over other systems for expression of eukaryotic proteins. In order to achieve this, the gene was cloned into the pPICZ alpha A expression vector, which was then incorporated into the P. pastoris genome via insertional integration for expression of the recombinant protein, under …


Mechanism Of N-Methylation By The Trna M1g37 Methyltransferase Trm5., Thomas Christian, Georges Lahoud, Cuiping Liu, Katherine Hoffmann, John J Perona, Ya-Ming Hou Dec 2010

Mechanism Of N-Methylation By The Trna M1g37 Methyltransferase Trm5., Thomas Christian, Georges Lahoud, Cuiping Liu, Katherine Hoffmann, John J Perona, Ya-Ming Hou

Department of Biochemistry and Molecular Biology Faculty Papers

Trm5 is a eukaryal and archaeal tRNA methyltransferase that catalyzes methyl transfer from S-adenosylmethionine (AdoMet) to the N(1) position of G37 directly 3' to the anticodon. While the biological role of m(1)G37 in enhancing translational fidelity is well established, the catalytic mechanism of Trm5 has remained obscure. To address the mechanism of Trm5 and more broadly the mechanism of N-methylation to nucleobases, we examined the pH-activity profile of an archaeal Trm5 enzyme, and performed structure-guided mutational analysis. The data reveal a marked dependence of enzyme-catalyzed methyl transfer on hydrogen ion equilibria: the single-turnover rate constant for methylation increases by one …


Dna Synapsis Through Transient Tetramerization Triggers Cleavage By Ecl18ki Restriction Enzyme., Mindaugas Zaremba, Amelia Owsicka, Gintautas Tamulaitis, Giedrius Sasnauskas, Luda S. Shlyakhtenko, Alexander Y. Lushnikov, Yuri L. Lyubchenko, Niels Laurens, Bram Van Den Broek, Gijs J.L. Wuite, Virginijus Siksnys Nov 2010

Dna Synapsis Through Transient Tetramerization Triggers Cleavage By Ecl18ki Restriction Enzyme., Mindaugas Zaremba, Amelia Owsicka, Gintautas Tamulaitis, Giedrius Sasnauskas, Luda S. Shlyakhtenko, Alexander Y. Lushnikov, Yuri L. Lyubchenko, Niels Laurens, Bram Van Den Broek, Gijs J.L. Wuite, Virginijus Siksnys

Journal Articles: Pharmaceutical Sciences

To cut DNA at their target sites, restriction enzymes assemble into different oligomeric structures. The Ecl18kI endonuclease in the crystal is arranged as a tetramer made of two dimers each bound to a DNA copy. However, free in solution Ecl18kI is a dimer. To find out whether the Ecl18kI dimer or tetramer represents the functionally important assembly, we generated mutants aimed at disrupting the putative dimer-dimer interface and analysed the functional properties of Ecl18kI and mutant variants. We show by atomic force microscopy that on two-site DNA, Ecl18kI loops out an intervening DNA fragment and forms a tetramer. Using the …


Wild-Type And Mutant Sod1 Share An Aberrant Conformation And A Common Pathogenic Pathway In Als., Daryl A Bosco, Gerardo Morfini, N Murat Karabacak, Yuyu Song, Francois Gros-Louis, Piera Pasinelli, Holly Goolsby, Benjamin A Fontaine, Nathan Lemay, Diane Mckenna-Yasek, Matthew P Frosch, Jeffrey N Agar, Jean-Pierre Julien, Scott T Brady, Robert H Brown Nov 2010

Wild-Type And Mutant Sod1 Share An Aberrant Conformation And A Common Pathogenic Pathway In Als., Daryl A Bosco, Gerardo Morfini, N Murat Karabacak, Yuyu Song, Francois Gros-Louis, Piera Pasinelli, Holly Goolsby, Benjamin A Fontaine, Nathan Lemay, Diane Mckenna-Yasek, Matthew P Frosch, Jeffrey N Agar, Jean-Pierre Julien, Scott T Brady, Robert H Brown

Farber Institute for Neuroscience Faculty Papers

Many mutations confer one or more toxic function(s) on copper/zinc superoxide dismutase 1 (SOD1) that impair motor neuron viability and cause familial amyotrophic lateral sclerosis (FALS). Using a conformation-specific antibody that detects misfolded SOD1 (C4F6), we found that oxidized wild-type SOD1 and mutant SOD1 share a conformational epitope that is not present in normal wild-type SOD1. In a subset of human sporadic ALS (SALS) cases, motor neurons in the lumbosacral spinal cord were markedly C4F6 immunoreactive, indicating that an aberrant wild-type SOD1 species was present. Recombinant, oxidized wild-type SOD1 and wild-type SOD1 immunopurified from SALS tissues inhibited kinesin-based fast axonal …


Phenotypic And Genotypic Analysis Of In Vitro Selected Artemisinin Resistant Plasmodium Falciparum, Matthew Scott Tucker Oct 2010

Phenotypic And Genotypic Analysis Of In Vitro Selected Artemisinin Resistant Plasmodium Falciparum, Matthew Scott Tucker

USF Tampa Graduate Theses and Dissertations

Artemisinin and its derivatives provide faster clearance of parasitemia than any other antimalarial drugs and these drugs are part of frontline combination therapies in areas where drug-resistant Plasmodium falciparum exists. Clinical resistance to artemisinins is emerging on the Thailand-Cambodia border, making it imperative to investigate mechanisms of artemisinin resistance. Previous work in our laboratory showed ring-stage parasites enter a dormant state after exposure to artemisinin. We hypothesize that this period of dormancy is directly related to recrudescence and prolonged parasite clearance times in patients, and possibly resistance. The target of artemisinin is currently unknown, and potential resistance mechanisms are not …


S100a1: A Multifaceted Therapeutic Target In Cardiovascular Disease., David Rohde, Julia Ritterhoff, Mirko Voelkers, Hugo A Katus, Thomas G Parker, Patrick Most Oct 2010

S100a1: A Multifaceted Therapeutic Target In Cardiovascular Disease., David Rohde, Julia Ritterhoff, Mirko Voelkers, Hugo A Katus, Thomas G Parker, Patrick Most

Department of Medicine Faculty Papers

Cardiovascular disease is the leading cause of death worldwide, showing a dramatically growing prevalence. It is still associated with a poor clinical prognosis, indicating insufficient long-term treatment success of currently available therapeutic strategies. Investigations of the pathomechanisms underlying cardiovascular disorders uncovered the Ca(2+) binding protein S100A1 as a critical regulator of both cardiac performance and vascular biology. In cardiomyocytes, S100A1 was found to interact with both the sarcoplasmic reticulum ATPase (SERCA2a) and the ryanodine receptor 2 (RyR2), resulting in substantially improved Ca(2+) handling and contractile performance. Additionally, S100A1 has been described to target the cardiac sarcomere and mitochondria, leading to …


The Mir-15/107 Group Of Microrna Genes: Evolutionary Biology, Cellular Functions, And Roles In Human Diseases, John R. Finnerty, Wang-Xia Wang, Sébastien S. Hébert, Bernard R. Wilfred, Guogen Mao, Peter T. Nelson Sep 2010

The Mir-15/107 Group Of Microrna Genes: Evolutionary Biology, Cellular Functions, And Roles In Human Diseases, John R. Finnerty, Wang-Xia Wang, Sébastien S. Hébert, Bernard R. Wilfred, Guogen Mao, Peter T. Nelson

Pathology and Laboratory Medicine Faculty Publications

The miR-15/107 group of microRNA (miRNA) gene is increasingly appreciated to serve key functions in humans. These miRNAs regulate gene expression involved in cell division, metabolism, stress response, and angiogenesis in vertebrate species. The miR-15/107 group has also been implicated in human cancers, cardiovascular disease and neurodegenerative disease, including Alzheimer's disease. Here we provide an overview of the following: (1) the evolution of miR-15/107 group member genes; (2) the expression levels of miRNAs in mammalian tissues; (3) evidence for overlapping gene-regulatory functions by different miRNAs; (4) the normal biochemical pathways regulated by miR-15/107 group miRNAs; and (5) the roles played …


Plasticity Of Lipid-Protein Interactions In The Function And Topogenesis Of The Membrane Protein Lactose Permease From Escherichia Coli, Mikhail Bogdanov, Philip Heacock, Ziqiang Guan, William Dowhan Aug 2010

Plasticity Of Lipid-Protein Interactions In The Function And Topogenesis Of The Membrane Protein Lactose Permease From Escherichia Coli, Mikhail Bogdanov, Philip Heacock, Ziqiang Guan, William Dowhan

Faculty and Staff Publications

Phosphatidylcholine (PC) has been widely used in place of naturally occurring phosphatidylethanolamine (PE) in reconstitution of bacterial membrane proteins. However, PC does not support native structure or function for several reconstituted transport proteins. Lactose permease (LacY) of Escherichia coli, when reconstituted in E. coli phospholipids, exhibits energy-dependent uphill and energy-independent downhill transport function and proper conformation of periplasmic domain P7, which is tightly linked to uphill transport function. LacY expressed in cells lacking PE and containing only anionic phospholipids exhibits only downhill transport and lacks native P7 conformation. Reconstitution of LacY in the presence of E. coli-derived PE, but not …


Control Of Catalytic Cycle By A Pair Of Analogous Trna Modification Enzymes., Thomas Christian, Georges Lahoud, Cuiping Liu, Ya-Ming Hou Jul 2010

Control Of Catalytic Cycle By A Pair Of Analogous Trna Modification Enzymes., Thomas Christian, Georges Lahoud, Cuiping Liu, Ya-Ming Hou

Department of Biochemistry and Molecular Biology Faculty Papers

Enzymes that use distinct active site structures to perform identical reactions are known as analogous enzymes. The isolation of analogous enzymes suggests the existence of multiple enzyme structural pathways that can catalyze the same chemical reaction. A fundamental question concerning analogous enzymes is whether their distinct active-site structures would confer the same or different kinetic constraints to the chemical reaction, particularly with respect to the control of enzyme turnover. Here, we address this question with the analogous enzymes of bacterial TrmD and its eukaryotic and archaeal counterpart Trm5. TrmD and Trm5 catalyze methyl transfer to synthesize the m1G37 base at …


Control Of Catalytic Cycle By A Pair Of Analogous Trna Modification Enzymes., Thomas Christian, Georges Lahoud, Cuiping Liu, Ya-Ming Hou Jul 2010

Control Of Catalytic Cycle By A Pair Of Analogous Trna Modification Enzymes., Thomas Christian, Georges Lahoud, Cuiping Liu, Ya-Ming Hou

Department of Biochemistry and Molecular Biology Faculty Papers

Enzymes that use distinct active site structures to perform identical reactions are known as analogous enzymes. The isolation of analogous enzymes suggests the existence of multiple enzyme structural pathways that can catalyze the same chemical reaction. A fundamental question concerning analogous enzymes is whether their distinct active-site structures would confer the same or different kinetic constraints to the chemical reaction, particularly with respect to the control of enzyme turnover. Here, we address this question with the analogous enzymes of bacterial TrmD and its eukaryotic and archaeal counterpart Trm5. TrmD and Trm5 catalyze methyl transfer to synthesize the m1G37 base at …


Ribosome Recycling Step In Yeast Cytoplasmic Protein Synthesis Is Catalyzed By Eef3 And Atp., Shinya Kurata, Klaus H Nielsen, Sarah F Mitchell, Jon R Lorsch, Akira Kaji, Hideko Kaji Jun 2010

Ribosome Recycling Step In Yeast Cytoplasmic Protein Synthesis Is Catalyzed By Eef3 And Atp., Shinya Kurata, Klaus H Nielsen, Sarah F Mitchell, Jon R Lorsch, Akira Kaji, Hideko Kaji

Department of Biochemistry and Molecular Biology Faculty Papers

After each round of protein biosynthesis, the posttermination complex (PoTC) consisting of a ribosome, mRNA, and tRNA must be disassembled into its components for a new round of translation. Here, we show that a Saccharomyces cerevisiae model PoTC was disassembled by ATP and eukaryotic elongation factor 3 (eEF3). GTP or ITP functioned with less efficiency and adenosine 5gamma'-(beta,gamma-imido)triphosphate did not function at all. The k(cat) of eEF3 was 1.12 min(-1), which is comparable to that of the in vitro initiation step. The disassembly reaction was inhibited by aminoglycosides and cycloheximide. The subunits formed from the yeast model PoTC remained separated …


Evolutionary Conservation Of Residues In Vertebrate Dna Polymerase N Conferring Low Fidelity And Bypass Activity, Kei-Ichi Takata, Mercedes E Arana, Mineaki Seki, Thomas A Kunkel, Richard D Wood Jun 2010

Evolutionary Conservation Of Residues In Vertebrate Dna Polymerase N Conferring Low Fidelity And Bypass Activity, Kei-Ichi Takata, Mercedes E Arana, Mineaki Seki, Thomas A Kunkel, Richard D Wood

Student and Faculty Publications

POLN is a nuclear A-family DNA polymerase encoded in vertebrate genomes. POLN has unusual fidelity and DNA lesion bypass properties, including strong strand displacement activity, low fidelity favoring incorporation of T for template G and accurate translesion synthesis past a 5S-thymine glycol (5S-Tg). We searched for conserved features of the polymerase domain that distinguish it from prokaryotic pol I-type DNA polymerases. A Lys residue (679 in human POLN) of particular interest was identified in the conserved 'O-helix' of motif 4 in the fingers sub-domain. The corresponding residue is one of the most important for controlling fidelity of prokaryotic pol I …


Structure Of Vibrio Cholerae Toxt Reveals A Mechanism For Fatty Acid Regulation Of Virulence Genes, Michael J. Lowden, Karen Skorupski, Maria Pellegrini, Michael G. Chiorazzo, Ronald K. Taylor, F. Jon Kull Feb 2010

Structure Of Vibrio Cholerae Toxt Reveals A Mechanism For Fatty Acid Regulation Of Virulence Genes, Michael J. Lowden, Karen Skorupski, Maria Pellegrini, Michael G. Chiorazzo, Ronald K. Taylor, F. Jon Kull

Dartmouth Scholarship

Cholera is an acute intestinal infection caused by the bacterium Vibrio cholerae. In order for V. cholerae to cause disease, it must produce two virulence factors, the toxin-coregulated pilus (TCP) and cholera toxin (CT), whose expression is controlled by a transcriptional cascade culminating with the expression of the AraC-family regulator, ToxT. We have solved the 1.9 A resolution crystal structure of ToxT, which reveals folds in the N- and C-terminal domains that share a number of features in common with AraC, MarA, and Rob as well as the unexpected presence of a buried 16-carbon fatty acid, cis-palmitoleate. The finding that …


Plasticity Of Oxidative Metabolism In Variable Climates: Molecular Mechanisms, Frank Seebacher, Martin D. Brand, Paul Else, Helga Guderley, Anthony J. Hulbert, Christopher D. Moyes Jan 2010

Plasticity Of Oxidative Metabolism In Variable Climates: Molecular Mechanisms, Frank Seebacher, Martin D. Brand, Paul Else, Helga Guderley, Anthony J. Hulbert, Christopher D. Moyes

Faculty of Health and Behavioural Sciences - Papers (Archive)

Converting food to chemical energy (ATP) that is usable by cells is a principal requirement to sustain life. The rate of ATP production has to be sufficient for housekeeping functions, such as protein synthesis and maintaining membrane potentials, as well as for growth and locomotion. Energy metabolism is temperature sensitive, and animals respond to environmental variability at different temporal levels, from within‐individual to evolutionary timescales. Here we review principal molecular mechanisms that underlie control of oxidative ATP production in response to climate variability. Nuclear transcription factors and coactivators control expression of mitochondrial proteins and abundance of mitochondria. Fatty acid and …


Molecular Characterization Of The Onset And Progression Of Colitis In Inoculated Interleukin-10 Gene-Deficient Mice: A Role For Pparcx, Bianca Knoch, Matthew Barnett, Janine Cooney, Warren Mcnabb, Diane Barraclough, William Laing, Shuotun Zhu, Zaneta A. Park, Paul Maclean, Scott O. Knowles, Nicole Roy Jan 2010

Molecular Characterization Of The Onset And Progression Of Colitis In Inoculated Interleukin-10 Gene-Deficient Mice: A Role For Pparcx, Bianca Knoch, Matthew Barnett, Janine Cooney, Warren Mcnabb, Diane Barraclough, William Laing, Shuotun Zhu, Zaneta A. Park, Paul Maclean, Scott O. Knowles, Nicole Roy

Illawarra Health and Medical Research Institute

The interleukin-10 gene-deficient (Il10−/−) mouse is a model of human inflammatory bowel disease and Ppara has been identified as one of the key genes involved in regulation of colitis in the bacterially inoculated Il10−/− model. The aims were to (1) characterize colitis onset and progression using a histopathological, transcriptomic, and proteomic approach and (2) investigate links between PPARα and IL10 using gene network analysis. Bacterial inoculation resulted in severe colitis in Il10−/− mice from 10 to 12 weeks of age. Innate and adaptive immune responses showed differences in gene expression relating to colitis severity. Actin cytoskeleton dynamics, innate immunity, and …