Medical Biochemistry Commons^™

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 …

Self-Protecting Bactericidal Titanium Alloy Surface Formed By Covalent Bonding Of Daptomycin Bisphosphonates., Chang-Po Chen, Eric Wickstrom

Department of Biochemistry and Molecular Biology Faculty Papers

Infections are a devastating complication of titanium alloy orthopedic implants. Current therapy includes antibiotic-impregnated bone cement and antibiotic-containing coatings. We hypothesized that daptomycin, a Gram-positive peptide antibiotic, could prevent bacterial colonization on titanium alloy surfaces if covalently bonded via a flexible, hydrophilic spacer. We designed and synthesized a series of daptomycin conjugates for bonding to the surface of 1.0 cm² Ti6Al4V foils through bisphosphonate groups, reaching a maximum yield of 180 pmol/cm². Daptomycin-bonded foils killed 53 ± 5% of a high challenge dose of 3 × 10⁵ cfu Staphylococcus aureus ATCC 29213.

Nanosized Hydroxyapatite And Other Calcium Phosphates: Chemistry Of Formation And Application As Drug And Gene Delivery Agents, Vuk Uskoković, Dragan Uskoković

Pharmacy Faculty Articles and Research

The first part of this review looks at the fundamental properties of hydroxyapatite (HAP), the basic mineral constituent of mammalian hard tissues, including the physicochemical features that govern its formation by precipitation. A special emphasis is placed on the analysis of qualities of different methods of synthesis and of the phase transformations intrinsic to the formation of HAP following precipitation from aqueous solutions. This serves as an introduction to the second part and the main subject of this review, which relates to the discourse regarding the prospects of fabrication of ultrafine, nanosized particles based on calcium phosphate carriers with various …

Biosynthesis: A New (Old) Way Of Hijacking Trna., Georges Lahoud, Ya-Ming Hou

Department of Biochemistry and Molecular Biology Faculty Papers

Aminoacylation of tRNA is the cellular process for providing aminoacyl donors for the ribosome synthesis of polypeptides. New research highlights an unexpected structural overlap between enzymes involved in this process and those involved in the biosynthesis of cyclodipeptides, an important class of bioactive molecules.

Insulin Degrading Enzyme Assays For Treatment Of Alzheimer's Disease, Louis B. Hersh

Molecular and Cellular Biochemistry Faculty Patents

Estrogen has been shown to increase the expression and activity of amyloid peptide inactivating enzymes in the brain. Peptides have been shown to increase the activity of an amyloid peptide inactivating enzyme. Methods of identifying compounds for, and methods of treating patients with, Alzheimer's Disease is disclosed.

Morphological Study Of Emulsion-Assisted Cholesterol Precipitation Processes, Vuk Uskoković

Pharmacy Faculty Articles and Research

Crystallization of cholesterol in chemical conditions that involve the presence of emulsions of three different types of surface active agents—cationic, anionic, and nonionic—was investigated by means of scanning and transmission electron microscopic analyses. In contrast with the previous attempts to modify the typical plate- and needle-shaped character of biaxially grown cholesterol crystals, the present study indicates that spherical templates of fine emulsion droplets may impose spherical morphologies to cholesterol particles nucleated within.

Identification Of Thioaptamer Ligand Against E-Selectin: Potential Application For Inflamed Vasculature Targeting., Aman P Mann, Anoma Somasunderam, René Nieves-Alicea, Xin Li, Austin Hu, Anil K Sood, Mauro Ferrari, David G Gorenstein, Takemi Tanaka

Department of Pharmacology and Experimental Therapeutics Faculty Papers

Active targeting of a drug carrier to a specific target site is crucial to provide a safe and efficient delivery of therapeutics and imaging contrast agents. E-selectin expression is induced on the endothelial cell surface of vessels in response to inflammatory stimuli but is absent in the normal vessels. Thus, E-selectin is an attractive molecular target, and high affinity ligands for E-selectin could be powerful tools for the delivery of therapeutics and/or imaging agents to inflamed vessels. In this study, we identified a thiophosphate modified aptamer (thioaptamer, TA) against E-selectin (ESTA-1) by employing a two-step selection strategy: a recombinant protein-based …

Radially Aligned, Electrospun Nanofibers As Dural Substitutes For Wound Closure And Tissue Regeneration Applications, Jingwei Xie, Matthew R. Macewan, Wilson Z. Ray, Wenying Liu, Daku Y. Siewe, Younan Xia

MIIR Faculty Research

This paper reports the fabrication of scaffolds consisting of radially aligned poly(ε-caprolactone) nanofibers by utilizing a collector composed of a central point electrode and a peripheral ring electrode. This novel class of scaffolds was able to present nanoscale topographic cues to cultured cells, directing and enhancing their migration from the periphery to the center. We also established that such scaffolds could induce faster cellular migration and population than nonwoven mats consisting of random nanofibers. Dural fibroblast cells cultured on these two types of scaffolds were found to express type I collagen, the main extracellular matrix component in dural mater. The …

A Smac Mimetic Reduces Tnf Related Apoptosis Inducing Ligand (Trail)-Induced Invasion And Metastasis Of Cholangiocarcinoma Cells., Christian D. Fingas, Boris R.A. Blechacz, Rory L. Smoot, Maria E. Guicciardi, Justin L. Mott, Steve F. Bronk, Nathan W. Werneburg, Alphonse E. Sirica, Gregory J. Gores

Journal Articles: Biochemistry & Molecular Biology

UNLABELLED: Cholangiocarcinoma (CCA) cells paradoxically express tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), a death ligand that, failing to kill CCA cells, instead promotes their tumorigenicity and especially the metastatic behaviors of cell migration and invasion. Second mitochondria-derived activator of caspase (smac) mimetics are promising cancer therapeutic agents that enhance proapoptotic death receptor signaling by causing cellular degradation of inhibitor of apoptosis (IAP) proteins. Our aim was to examine the in vitro and in vivo effects of the smac mimetic JP1584 in CCA. Despite JP1584-mediated loss of cellular inhibitor of apoptosis-1 (cIAP-1) and cIAP-2, TRAIL failed to induce apoptosis in KMCH-1, …

Transcriptional Suppression Of Mir-29b-1/Mir-29a Promoter By C-Myc, Hedgehog, And Nf-Kappab., Justin L. Mott, Satoshi Kurita, Sophie C. Cazanave, Steven F. Bronk, Nathan W. Werneburg, Martin E. Fernandez-Zapico

Journal Articles: Biochemistry & Molecular Biology

MicroRNAs regulate pathways contributing to oncogenesis, and thus the mechanisms causing dysregulation of microRNA expression in cancer are of significant interest. Mature mir-29b levels are decreased in malignant cells, and this alteration promotes the malignant phenotype, including apoptosis resistance. However, the mechanism responsible for mir-29b suppression is unknown. Here, we examined mir-29 expression from chromosome 7q32 using cholangiocarcinoma cells as a model for mir-29b downregulation. Using 5' rapid amplification of cDNA ends, the transcriptional start site was identified for this microRNA locus. Computational analysis revealed the presence of two putative E-box (Myc-binding) sites, a Gli-binding site, and four NF-kappaB-binding sites …

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

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 …

Noxa Mediates Hepatic Stellate Cell Apoptosis By Proteasome Inhibition., Ivette M. Sosa Seda, Justin L. Mott, Yuko Akazawa, Fernando J. Barreyro, Steven F. Bronk, Scott H. Kaufmann, Gregory J. Gores

Journal Articles: Biochemistry & Molecular Biology

Aim: Induction of hepatic stellate cell (HSC) apoptosis is a viable therapeutic strategy to reduce liver fibrogenesis. Although BH3-only proteins of the Bcl-2 family trigger pro-apoptotic pathways, the BH3-only proteins mediating HSC apoptosis have not been well defined. Our aim, using proteasome inhibition as a model to induce HSC apoptosis, was to examine the BH3-only proteins contributing to cell death of this key liver cell subtype. Methods: Apoptosis was induced by treating LX-2 cells, an immortalized human hepatic stellate cell line, and primary rat stellate cells with the proteasome inhibitor MG-132. Results: Treatment with proteasome inhibitors increased expression of Noxa …

Antibodies And Unnatural Substrates Of Prenylation Enzymes For Use In Detecting And Isolating Prenylated Proteins, H. Peter Spielmann, Douglas A. Andres

Molecular and Cellular Biochemistry Faculty Patents

Unnatural substrates of prenylation enzymens and antibodies that recognize unique moieties of prenylated proteins, which unique moieties are transferred from the unnatural substrates are used for detecting and isolating prenylated proteins, and for screening for inhibitors of prenylation enzymes.

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 …

Reducing The Effects Of Intracellular Accumulation Of Thermolabile Collagen Ii Mutants By Increasing Their Thermostability In Cell Culture Conditions., Katarzyna Gawron, Deborah A. Jensen, Andrzej Steplewski, Andrzej Fertala

Department of Dermatology and Cutaneous Biology Faculty Papers

Mutations in collagen II are associated with spondyloepiphyseal dysplasia, a group of heritable diseases whose common features include aberrations of skeletal growth. The mechanisms through which mutations in collagen II affect the cartilaginous tissues are complex and include both intracellular and extracellular processes. One of those mechanisms involves cellular stress caused by excessive accumulation of misfolded collagen II mutants. We investigated whether stabilizing the structure of thermolabile R789C and R992C collagen II mutants would improve their secretion from cells, thereby reducing cellular stress and apoptosis. Employing glycerol and trimethylamine N-oxide (TMAO), chemicals that increase the thermostability of collagen triple helices, …

Ns1 Of H5n1 Interacts With Sap-97 In A Pdz-Dependent Manner To Disrupt Epithelial Barrier Integrity, Veronica Garcia Conoley

Theses and Dissertations (ETD)

The ability of influenza A virus to cause global pandemics has been a great concern throughout history and poses a serious health risk worldwide. Pandemic outbreaks throughout history, such as the Spanish flu of 1918, have claimed the lives of millions of people worldwide. The current outbreak of avian influenza (H5N1) that began in 1997 is still claiming lives, and therefore efforts to understand the mechanisms of pathogenesis in this highly virulent virus are of the utmost importance. According to the World Health Organization, there have been 447 reported H5N1 human cases, resulting in 263 deaths. The pathology of H5N1 …

Capsaicin Displays Anti-Proliferative Activity Against Human Small Cell Lung Cancer In Cell Culture And Nude Mice Models Via The E2f Pathway, Kathleen C. Brown, Theodore R. Witte, W. Elaine Hardman, Haitao Luo, Yi C. Chen, A. Betts Carpenter, Jamie K. Lau, Piyali Dasgupta

Biochemistry and Microbiology

Background: Small cell lung cancer (SCLC) is characterized by rapid progression and low survival rates. Therefore, novel therapeutic agents are urgently needed for this disease. Capsaicin, the active ingredient of chilli peppers, displays antiproliferative activity in prostate and epidermoid cancer in vitro. However, the anti-proliferative activity of capsaicin has not been studied in human SCLCs. The present manuscript fills this void of knowledge and explores the anti-proliferative effect of capsaicin in SCLC in vitro and in vivo.

Methodology/Principal Findings: BrdU assays and PCNA ELISAs showed that capsaicin displays robust anti-proliferative activity in four human SCLC cell lines. Furthermore, capsaicin potently …

Mbp-1 Upregulates Mir-29b That Represses Mcl-1, Collagens, And Matrix-Metalloproteinase-2 In Prostate Cancer Cells., Robert Steele, Justin L. Mott, Ratna B. Ray

Journal Articles: Biochemistry & Molecular Biology

c-myc promoter binding protein (MBP-1) is a multi-functional protein known to regulate expression of targets involved in the malignant phenotype. We have previously demonstrated that exogenous expression of MBP-1 inhibits prostate tumor growth, although the mechanism of growth inhibition is not well understood. We hypothesized that MBP-1 may modulate microRNA (miRNA) expression for regulation of prostate cancer cell growth. In this study, we demonstrated that exogenous MBP-1 upregulates miR-29b by 5-9 fold in prostate cancer cells as measured by real-time quantitative reverse transcription-PCR. Subsequent studies indicated that exogenous expression of miR-29b inhibited Mcl-1, COL1A1, and COL4A1. Further, a novel target …

Palmitoleate Attenuates Palmitate-Induced Bim And Puma Up-Regulation And Hepatocyte Lipoapoptosis., Yuko Akazawa, Sophie Cazanave, Justin L. Mott, Nafisa Elmi, Steven F. Bronk, Shigeru Kohno, Michael R. Charlton, Gregory J. Gores

Journal Articles: Biochemistry & Molecular Biology

BACKGROUND & AIMS: Saturated free fatty acids induce hepatocyte lipoapoptosis. This lipotoxicity involves an endoplasmic reticulum stress response, activation of JNK, and altered expression and function of Bcl-2 proteins. The mono-unsaturated free fatty acid palmitoleate is an adipose-derived lipokine which suppresses free fatty acid-mediated lipotoxicity by unclear mechanisms. Herein we examined the mechanisms responsible for cytoprotection.

METHODS: We employed isolated human and mouse primary hepatocytes, and the Huh-7 and Hep 3B cell lines for these studies. Cells were incubated in presence and absence of palmitate (16:0), stearate (18:0), and or palmitoleate (16:1, n-7).

RESULTS: Palmitoleate significantly reduced lipoapoptosis by palmitate …