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Articles 91 - 120 of 227

Full-Text Articles in Nucleic Acids, Nucleotides, and Nucleosides

A Purification And In Vitro Activity Assay For A (P)Ppgpp Synthetase From Clostridium Difficile, Astha Pokhrel, Asia Poudel, Erin B. Purcell Jan 2018

A Purification And In Vitro Activity Assay For A (P)Ppgpp Synthetase From Clostridium Difficile, Astha Pokhrel, Asia Poudel, Erin B. Purcell

Chemistry & Biochemistry Faculty Publications

Kinase and pyrophosphokinase enzymes transfer the gamma phosphate or the beta-gamma pyrophosphate moiety from nucleotide triphosphate precursors to substrates to create phosphorylated products. The use of γ-32-P labeled NTP precursors allows simultaneous monitoring of substrate utilization and product formation by radiography. Thin layer chromatography (TLC) on cellulose plates allows rapid separation and sensitive quantification of substrate and product. We present a method for utilizing the thin-layer chromatography to assay the pyrophosphokinase activity of a purified (p)ppGpp synthetase. This method has previously been used to characterize the activity of cyclic nucleotide and dinucleotide synthetases and is broadly suitable for …


The Development Of Microfluidic Devices For The Production Of Safe And Effective Non-Viral Gene Delivery Vectors, Jason Matthew Absher Jan 2018

The Development Of Microfluidic Devices For The Production Of Safe And Effective Non-Viral Gene Delivery Vectors, Jason Matthew Absher

Theses and Dissertations--Chemical and Materials Engineering

Including inherited genetic diseases, like lipoprotein lipase deficiency, and acquired diseases, such as cancer and HIV, gene therapy has the potential to treat or cure afflicted people by driving an affected cell to produce a therapeutic protein. Using primarily viral vectors, gene therapies are involved in a number of ongoing clinical trials and have already been approved by multiple international regulatory drug administrations for several diseases. However, viral vectors suffer from serious disadvantages including poor transduction of many cell types, immunogenicity, direct tissue toxicity and lack of targetability. Non-viral polymeric gene delivery vectors (polyplexes) provide an alternative solution but are …


Modification Of The Ribosome As Part Of The Adaptive Response To Oxidative Stress In Yeast, Jessica A Zinskie, Daniel Shedlovskiy, Ethan Gardner, Dimitri G Pestov, Natalia Shcherbik Dec 2017

Modification Of The Ribosome As Part Of The Adaptive Response To Oxidative Stress In Yeast, Jessica A Zinskie, Daniel Shedlovskiy, Ethan Gardner, Dimitri G Pestov, Natalia Shcherbik

Rowan-Virtua School of Osteopathic Medicine Departmental Research

Living organisms are constantly exposed to a variety of environmental and internal stressors tha tare detrimental to their cellular physiology and viability. One such condition, oxidativestress, is caused by abnormal amounts of Reactive Oxygen Species (ROS) that can lead to damage to proteins, nucleic acids, and lipids. Although the mechanisms to neutralize ROS have been widely studied, the understanding of ROS‐mediated signaling for these mechanisms is rather incomplete and sparse. We have uncovered a previously undescribed phenomenon of yeast ribosomes to respond to elevated levels of ROS through a specific endonucleolytic cleavage of the 25S rRNA in the c‐loop of …


Synthesis Of 2,4,6-Substituted Pyrrolo[2,3-D]Pyrimidines As Potential Anticancer Agents, Si Yang Dec 2017

Synthesis Of 2,4,6-Substituted Pyrrolo[2,3-D]Pyrimidines As Potential Anticancer Agents, Si Yang

Electronic Theses and Dissertations

This thesis mainly focuses on the introduction of the background and work have been done in the areas of antifolates development, such as folate function, its three uptake mechanisms inside human cells, antifolates’ role in chemotherapy, et. al. In addition, the Structure-Activity-Relationship design rationale for the series of antifolates will also be discussed. Nevertheless, the details of synthesizing these pyrrolo[2,3-d]pyrimidines as potential antifolates have been described, including chemistry reviews on the pyrrolo[2,3-d]pyrimidine scaffold, and the challenges encountered and the solutions how to solve or improve in order to achieve better yield.


Size, Shape, And Sequence-Dependent Immunogenicity Of Rna Nanoparticles, Sijin Guo, Hui Li, Mengshi Ma, Jian Fu, Yizhou Dong, Peixuan Guo Nov 2017

Size, Shape, And Sequence-Dependent Immunogenicity Of Rna Nanoparticles, Sijin Guo, Hui Li, Mengshi Ma, Jian Fu, Yizhou Dong, Peixuan Guo

Center for Research on Environmental Disease Faculty Publications

RNA molecules have emerged as promising therapeutics. Like all other drugs, the safety profile and immune response are important criteria for drug evaluation. However, the literature on RNA immunogenicity has been controversial. Here, we used the approach of RNA nanotechnology to demonstrate that the immune response of RNA nanoparticles is size, shape, and sequence dependent. RNA triangle, square, pentagon, and tetrahedron with same shape but different sizes, or same size but different shapes were used as models to investigate the immune response. The levels of pro-inflammatory cytokines induced by these RNA nanoarchitectures were assessed in macrophage-like cells and animals. It …


Mutsβ Abundance And Msh3 Atp Hydrolysis Activity Are Important Drivers Of Ctg•Cag Repeat Expansions, Norma Keogh, Kara Y. Chan, Guo-Min Li, Robert S. Lahue Sep 2017

Mutsβ Abundance And Msh3 Atp Hydrolysis Activity Are Important Drivers Of Ctg•Cag Repeat Expansions, Norma Keogh, Kara Y. Chan, Guo-Min Li, Robert S. Lahue

Toxicology and Cancer Biology Faculty Publications

CTG•CAG repeat expansions cause at least twelve inherited neurological diseases. Expansions require the presence, not the absence, of the mismatch repair protein MutSβ (Msh2-Msh3 heterodimer). To evaluate properties of MutSβ that drive expansions, previous studies have tested under-expression, ATPase function or polymorphic variants of Msh2 and Msh3, but in disparate experimental systems. Additionally, some variants destabilize MutSβ, potentially masking the effects of biochemical alterations of the variations. Here, human Msh3 was mutated to selectively inactivate MutSβ. Msh3−/− cells are severely defective for CTG•CAG repeat expansions but show full activity on contractions. Msh3−/− cells provide a single, isogenic system …


Synthesis And Photophysical Studies Of Pyrrolocytosine Derivatives, Atefeh Rouhi Sep 2017

Synthesis And Photophysical Studies Of Pyrrolocytosine Derivatives, Atefeh Rouhi

Electronic Thesis and Dissertation Repository

Pyrrolocytosine (pC) derivatives are used in the study of nucleic acid structure, function and in the design of the hybridization probes. They have unique properties including small size and Watson-Crick base pairing capability and impressive fluorescent properties. However, they exhibit variation in the fluorescence properties upon incorporation into single-stranded DNA and double-stranded DNA.

This study analyzes the effect of the nearest neighbours on the fluorescence properties of phenylpyrrolocytosine (PhpC) and provides a guide to the proper design of the PhpC containing fluorescent probes. Moreover, the possibility of photoinduced electron transfer (PET) as the underlying mechanism of the unusual photophysical behavior …


Epigenetic Instability Induced By Dna Base Lesion Via Dna Base Excision Repair, Zhongliang Jiang Sep 2017

Epigenetic Instability Induced By Dna Base Lesion Via Dna Base Excision Repair, Zhongliang Jiang

FIU Electronic Theses and Dissertations

DNA damage can cause genome instability, which may lead to human cancer. The most common form of DNA damage is DNA base damage, which is efficiently repaired by DNA base excision repair (BER). Thus BER is the major DNA repair pathway that maintains the stability of the genome. On the other hand, BER mediates DNA demethylation that can occur on the promoter region of important tumor suppressor genes such as Breast Cancer 1 (BRCA1) gene that is also involved in prevention and development of cancer. In this study, employing cell-based and in vitro biochemical approaches along with bisulfite DNA sequencing, …


Translational Fidelity, Mistranslation, And The Cellular Responses To Stress, Kyle Mohler, Michael Ibba Aug 2017

Translational Fidelity, Mistranslation, And The Cellular Responses To Stress, Kyle Mohler, Michael Ibba

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Faithful translation of mRNA into the corresponding polypeptide is a complex multistep process, requiring accurate amino acid selection, transfer RNA (tRNA) charging and mRNA decoding on the ribosome. Key players in this process are aminoacyl-tRNA synthetases (aaRSs), which not only catalyse the attachment of cognate amino acids to their respective tRNAs, but also selectively hydrolyse incorrectly activated non-cognate amino acids and/or misaminoacylated tRNAs. This aaRS proofreading provides quality control checkpoints that exclude non-cognate amino acids during translation, and in so doing helps to prevent the formation of an aberrant proteome. However, despite the intrinsic need for high accuracy during translation, …


Carbonyl Reduction By Ymfi Completes The Modification Of Ef-P In Bacillus Subtilis To Prevent Accumulation Of An Inhibitory Modification State, Katherine R. Hummels, Anne Witzky, Andrei Rajkovic, Rodney Tollerson Ii, Lisa A. Jones, Michael Ibba, Daniel B. Kearns Aug 2017

Carbonyl Reduction By Ymfi Completes The Modification Of Ef-P In Bacillus Subtilis To Prevent Accumulation Of An Inhibitory Modification State, Katherine R. Hummels, Anne Witzky, Andrei Rajkovic, Rodney Tollerson Ii, Lisa A. Jones, Michael Ibba, Daniel B. Kearns

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Translation elongation factor P (EF‐P) in Bacillus subtilis is required for a form of surface migration called swarming motility. Furthermore, B. subtilis EF‐P is post‐translationally modified with a 5‐aminopentanol group but the pathway necessary for the synthesis and ligation of the modification is unknown. Here we determine that the protein YmfI catalyzes the reduction of EF‐P‐5 aminopentanone to EF‐P‐5 aminopentanol. In the absence of YmfI, accumulation of 5‐aminopentanonated EF‐P is inhibitory to swarming motility. Suppressor mutations that enhanced swarming in the absence of YmfI were found at two positions on EF‐P, including one that changed the conserved modification site (Lys …


Elongation Factor P Interactions With The Ribosome Are Independent Of Pausing, Rodney Tollerson Ii, Anne Witzky, Michael Ibba Aug 2017

Elongation Factor P Interactions With The Ribosome Are Independent Of Pausing, Rodney Tollerson Ii, Anne Witzky, Michael Ibba

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Bacterial elongation factor P (EF-P) plays a pivotal role in the translation of polyproline motifs. To stimulate peptide bond formation, EF-P must enter the ribosome via an empty E-site. Using fluorescence-based single-molecule tracking, Mohapatra et al. (S. Mohapatra, H. Choi, X. Ge, S. Sanyal, and J. C. Weisshaar, mBio 8:e00300-17, 2017, https://doi.org/10.1128/mBio.00300-17 ) monitored the cellular distribution of EF-P and quantified the frequency of association between EF-P and the ribosome under various conditions. Findings from the study showed that EF-P has a localization pattern that is strikingly similar to that of ribosomes. Intriguingly, EF-P was seen to bind ribosomes more …


Regulation And Modulation Of Human Dna Polymerase Δ Activity And Function, Marietta Y W T Lee, Xiaoxiao Wang, Sufang Zhang, Zhongtao Zhang, Ernest Y C Lee Jul 2017

Regulation And Modulation Of Human Dna Polymerase Δ Activity And Function, Marietta Y W T Lee, Xiaoxiao Wang, Sufang Zhang, Zhongtao Zhang, Ernest Y C Lee

NYMC Faculty Publications

This review focuses on the regulation and modulation of human DNA polymerase δ (Pol δ). The emphasis is on the mechanisms that regulate the activity and properties of Pol δ in DNA repair and replication. The areas covered are the degradation of the p12 subunit of Pol δ, which converts it from a heterotetramer (Pol δ4) to a heterotrimer (Pol δ3), in response to DNA damage and also during the cell cycle. The biochemical mechanisms that lead to degradation of p12 are reviewed, as well as the properties of Pol δ4 and Pol δ3 that provide insights into their functions …


Quaternary Interactions And Supercoiling Modulate The Cooperative Dna Binding Of Agt, Manana Melikishvili, Michael G. Fried Jul 2017

Quaternary Interactions And Supercoiling Modulate The Cooperative Dna Binding Of Agt, Manana Melikishvili, Michael G. Fried

Center for Structural Biology Faculty Publications

Human O6-alkylguanine-DNA alkyltransferase (AGT) repairs mutagenic O6-alkylguanine and O4-alkylthymine adducts in single-stranded and duplex DNAs. The search for these lesions, through a vast excess of competing, unmodified genomic DNA, is a mechanistic challenge that may limit the repair rate in vivo. Here, we examine influences of DNA secondary structure and twist on protein–protein interactions in cooperative AGT complexes formed on lesion-free DNAs that model the unmodified parts of the genome. We used a new approach to resolve nearest neighbor (nn) and long-range (lr) components from the ensemble-average cooperativity, ωave. We found …


Identification Of A Nucleoside Analog Active Against Adenosine Kinase-Expressing Plasma Cell Malignancies, Utthara Nayar, Jouliana Sadek, Jonathan Reichel, Denise Hernandez-Hopkins, Gunkut Akar, Peter J. Barelli, Michelle A. Sahai, Hufeng Zhou, Jennifer Totonchy, David Jayabalan, Ruben Niesvizky, Ilaria Guasparri, Duane Hassane, Yifang Liu, Shizuko Sei, Robert H. Shoemaker, J. David Warren, Olivier Elemento, Kenneth M. Kaye, Ethel Cesarman Jun 2017

Identification Of A Nucleoside Analog Active Against Adenosine Kinase-Expressing Plasma Cell Malignancies, Utthara Nayar, Jouliana Sadek, Jonathan Reichel, Denise Hernandez-Hopkins, Gunkut Akar, Peter J. Barelli, Michelle A. Sahai, Hufeng Zhou, Jennifer Totonchy, David Jayabalan, Ruben Niesvizky, Ilaria Guasparri, Duane Hassane, Yifang Liu, Shizuko Sei, Robert H. Shoemaker, J. David Warren, Olivier Elemento, Kenneth M. Kaye, Ethel Cesarman

Pharmacy Faculty Articles and Research

Primary effusion lymphoma (PEL) is a largely incurable malignancy of B cell origin with plasmacytic differentiation. Here, we report the identification of a highly effective inhibitor of PEL. This compound, 6-ethylthioinosine (6-ETI), is a nucleoside analog with toxicity to PEL in vitro and in vivo, but not to other lymphoma cell lines tested. We developed and performed resistome analysis, an unbiased approach based on RNA sequencing of resistant subclones, to discover the molecular mechanisms of sensitivity. We found different adenosine kinase–inactivating (ADK-inactivating) alterations in all resistant clones and determined that ADK is required to phosphorylate and activate 6-ETI. Further, we …


Diversity Oriented Synthesis, Characterization And Anti-Cancer Activity Of Killer Peptide Nucleolipid Bioconjugates, Niki K. Rana May 2017

Diversity Oriented Synthesis, Characterization And Anti-Cancer Activity Of Killer Peptide Nucleolipid Bioconjugates, Niki K. Rana

Seton Hall University Dissertations and Theses (ETDs)

The killer peptide sequence D-(KLAKLAK)2 has been originally designed and developed as an antibacterial agent. Despite having excellent cytotoxicity towards bacteria, this sequence maintains low cell cytotoxity in malignant mammalian cell types such as cancer. The chemical basis for its selectivity has been attributed to its poly(cationic) amphiphilic nature, which facilitates cell permeability across the negatively charged bacterial membrane, but with limited permeability across the zwitterionic membrane of mammalian cells. The positively charged D-(KLAKLAK)2 sequence has been found to accumulate on the surface of the mitochondria causing dissipation of the negatively charged mitochondrial membrane potential. This charge disruption …


Investigating The Mechanism Of Novel Anticancer Agent, As1411 : Does Metabolism To Guanine Play A Role?, Parker T Howard May 2017

Investigating The Mechanism Of Novel Anticancer Agent, As1411 : Does Metabolism To Guanine Play A Role?, Parker T Howard

College of Arts & Sciences Senior Honors Theses

AS1411 is an oligonucleotide that has shown promising results in lab experiments and clinical trials as an anti-cancer drug, Likewise, treatments with guanine based purine compounds (GBPCs) have demonstrated similar anti-proliferative effects in vitro. This activity is dependent on the HGPRT enzyme. Similarities in activity and physical structure has led us to believe that AS1411 and GBPCs operate by a similar mechanism. To test this, we compare the activity of both in the presence of HGPRT siRNAs and HGPRT deficient cells. While siRNA treatment was unable to alter the activity of GBPCs or AS1411 in our cell lines, HGPRT deficient …


Functionalization Of Peptide Nucleic Acids Via Post-Synthetic Click Chemistry, Xiaoxiao Wang Apr 2017

Functionalization Of Peptide Nucleic Acids Via Post-Synthetic Click Chemistry, Xiaoxiao Wang

Electronic Thesis and Dissertation Repository

Peptide Nucleic Acid (PNA) has shown great potential in molecular diagnostics, antisense/antigene therapy and nanotechnology. Like other synthetic nucleic acids and artificial analogues, PNA has been extensively modified to achieve better performance in these applications. To efficiently develop PNA probes for molecular diagnosis, this thesis is focused on versatile functionalization of PNA via post-synthetic click chemistry.

Chapter 2 presents the synthesis of quencher-free PNA molecular beacons (MBs) targeting a cystic fibrosis transmembrane conductance regulator (CFTR) sequence mutation. To avoid the tedious synthesis of functionalized PNA monomers for probe development, a simple approach to modify PNA oligomers by post-synthetic on-resin click …


Editing Of Misaminoacylated Trna Controls The Sensitivity Of Amino Acid Stress Responses In Saccharomyces Cerevisiae, Kyle Mohler, Rebecca Mann, Tammy J. Bullwinkle, Kyle W. Hopkins, Lin Hwang, Noah M. Reynolds, Brandon Gassaway, Hans-Rudolph Aerni, Jesse Rinehart, Michael Polymenis, Kym F. Faull, Michael Ibba Feb 2017

Editing Of Misaminoacylated Trna Controls The Sensitivity Of Amino Acid Stress Responses In Saccharomyces Cerevisiae, Kyle Mohler, Rebecca Mann, Tammy J. Bullwinkle, Kyle W. Hopkins, Lin Hwang, Noah M. Reynolds, Brandon Gassaway, Hans-Rudolph Aerni, Jesse Rinehart, Michael Polymenis, Kym F. Faull, Michael Ibba

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Amino acid starvation activates the protein kinase Gcn2p, leading to changes in gene expression and translation. Gcn2p is activated by deacylated tRNA, which accumulates when tRNA aminoacylation is limited by lack of substrates or inhibition of synthesis. Pairing of amino acids and deacylated tRNAs is catalyzed by aminoacyl-tRNA synthetases, which use quality control pathways to maintain substrate specificity. Phenylalanyl-tRNA synthetase (PheRS) maintains specificity via an editing pathway that targets non-cognate Tyr-tRNAPhe. While the primary role of aaRS editing is to prevent misaminoacylation, we demonstrate editing of misaminoacylated tRNA is also required for detection of amino acid starvation by …


Quality Control By Isoleucyl-Trna Synthetase Of Bacillus Subtilis Is Required For Efficient Sporulation, Elizabeth Kermgard, Zhou Yang, Annika-Marisa Michel, Rachel Simari, Jacqueline Wong, Michael Ibba, Beth A. Lazazzera Jan 2017

Quality Control By Isoleucyl-Trna Synthetase Of Bacillus Subtilis Is Required For Efficient Sporulation, Elizabeth Kermgard, Zhou Yang, Annika-Marisa Michel, Rachel Simari, Jacqueline Wong, Michael Ibba, Beth A. Lazazzera

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Isoleucyl-tRNA synthetase (IleRS) is an aminoacyl-tRNA synthetase whose essential function is to aminoacylate tRNAIle with isoleucine. Like some other aminoacyl-tRNA synthetases, IleRS can mischarge tRNAIle and correct this misacylation through a separate post-transfer editing function. To explore the biological significance of this editing function, we created a ileS(T233P) mutant of Bacillus subtilis that allows tRNAIle mischarging while retaining wild-type Ile-tRNAIle synthesis activity. As seen in other species defective for aminoacylation quality control, the growth rate of the ileS(T233P) strain was not significantly different from wild-type. When the ileS(T233P) strain was assessed for its ability to promote …


Ms-Read: Quantitative Measurement Of Amino Acid Incorporation, Kyle Mohler, Hans-Rudolph Aerni, Brandon Gassaway, Jiqiang Ling, Michael Ibba, Jesse Rinehart Jan 2017

Ms-Read: Quantitative Measurement Of Amino Acid Incorporation, Kyle Mohler, Hans-Rudolph Aerni, Brandon Gassaway, Jiqiang Ling, Michael Ibba, Jesse Rinehart

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Ribosomal protein synthesis results in the genetically programmed incorporation of amino acids into a growing polypeptide chain. Faithful amino acid incorporation that accurately reflects the genetic code is critical to the structure and function of proteins as well as overall proteome integrity. Errors in protein synthesis are generally detrimental to cellular processes yet emerging evidence suggest that proteome diversity generated through mistranslation may be beneficial under certain conditions. Cumulative translational error rates have been determined at the organismal level, however codon specific error rates and the spectrum of misincorporation errors from system to system remain largely unexplored. In particular, until …


Development Of Diverse Size And Shape Rna Nanoparticles And Investigation Of Their Physicochemical Properties For Optimized Drug Delivery, Daniel L. Jasinski Jan 2017

Development Of Diverse Size And Shape Rna Nanoparticles And Investigation Of Their Physicochemical Properties For Optimized Drug Delivery, Daniel L. Jasinski

Theses and Dissertations--Pharmacy

RNA nanotechnology is an emerging field that holds great promise for advancing drug delivery and materials science. Recently, RNA nanoparticles have seen increased use as an in vivo delivery system. RNA was once thought to have little potential for in vivo use due to biological and thermodynamic stability issues. However, these issues have been solved by: (1) Finding of a thermodynamically stable three-way junction (3WJ) motif; (2) Chemical modifications to RNA confer enzymatic stability in vivo; and (3) the finding that RNA nanoparticles exhibit low immunogenicity in vivo.

In vivo biodistribution and pharmacokinetics are affected by the physicochemical …


Synthesis Of Rhamnosylated Arginine Glycopeptides And Determination Of The Glycosidic Linkage In Bacterial Elongation Factor P, Siyao Wang, Leo Corcilius, Phillip B. Sharp, Andrei Rajkovic, Michael Ibba, Benjamin L. Parker, Richard J. Payne Dec 2016

Synthesis Of Rhamnosylated Arginine Glycopeptides And Determination Of The Glycosidic Linkage In Bacterial Elongation Factor P, Siyao Wang, Leo Corcilius, Phillip B. Sharp, Andrei Rajkovic, Michael Ibba, Benjamin L. Parker, Richard J. Payne

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

A new class of N-linked protein glycosylation – arginine rhamnosylation – has recently been discovered as a critical modification for the function of bacterial elongation factor P (EF-P). Herein, we describe the synthesis of suitably protected α- and β-rhamnosylated arginine amino acid “cassettes” that can be directly installed into rhamnosylated peptides. Preparation of a proteolytic fragment of Pseudomonas aeruginosa EF-P bearing both α- and β-rhamnosylated arginine enabled the unequivocal determination of the native glycosidic linkage to be α through 2D NMR and nano-UHPLC-tandem mass spectrometry studies.


The Complex Evolutionary History Of Aminoacyl-Trna Synthetases, Anargyros Chaliotis, Panayotis Vlastaridis, Dimitris Mossialos, Michael Ibba, Hubert D. Becker, Constantinos Stathopoulos, Grigorios D. Amoutzias Nov 2016

The Complex Evolutionary History Of Aminoacyl-Trna Synthetases, Anargyros Chaliotis, Panayotis Vlastaridis, Dimitris Mossialos, Michael Ibba, Hubert D. Becker, Constantinos Stathopoulos, Grigorios D. Amoutzias

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Aminoacyl-tRNA synthetases (AARSs) are a superfamily of enzymes responsible for the faithful translation of the genetic code and have lately become a prominent target for synthetic biologists. Our large-scale analysis of >2500 prokaryotic genomes reveals the complex evolutionary history of these enzymes and their paralogs, in which horizontal gene transfer played an important role. These results show that a widespread belief in the evolutionary stability of this superfamily is misconceived. Although AlaRS, GlyRS, LeuRS, IleRS, ValRS are the most stable members of the family, GluRS, LysRS and CysRS often have paralogs, whereas AsnRS, GlnRS, PylRS and SepRS are often absent …


Structures Of Mithramycin Analogues Bound To Dna And Implications For Targeting Transcription Factor Fli1, Caixia Hou, Stevi Weidenbach, Kristin E. Cano, Zhonghua Wang, Prithiba Mitra, Dmitri N. Ivanov, Jürgen Rohr, Oleg V. Tsodikov Oct 2016

Structures Of Mithramycin Analogues Bound To Dna And Implications For Targeting Transcription Factor Fli1, Caixia Hou, Stevi Weidenbach, Kristin E. Cano, Zhonghua Wang, Prithiba Mitra, Dmitri N. Ivanov, Jürgen Rohr, Oleg V. Tsodikov

Pharmaceutical Sciences Faculty Publications

Transcription factors have been considered undruggable, but this paradigm has been recently challenged. DNA binding natural product mithramycin (MTM) is a potent antagonist of oncogenic transcription factor EWS–FLI1. Structural details of MTM recognition of DNA, including the FLI1 binding sequence GGA(A/T), are needed to understand how MTM interferes with EWS–FLI1. We report a crystal structure of an MTM analogue MTM SA–Trp bound to a DNA oligomer containing a site GGCC, and two structures of a novel analogue MTM SA–Phe in complex with DNA. MTM SA–Phe is bound to sites AGGG and GGGT on one DNA, and to AGGG and GGGA(T) …


Isoacceptor Specific Characterization Of Trna Aminoacylation And Misacylation In Vivo, Kyle Mohler, Rebecca Mann, Michael Ibba Sep 2016

Isoacceptor Specific Characterization Of Trna Aminoacylation And Misacylation In Vivo, Kyle Mohler, Rebecca Mann, Michael Ibba

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Amino acid misincorporation during protein synthesis occurs due to misacylation of tRNAs or defects in decoding at the ribosome. While misincorporation of amino acids has been observed in a variety of contexts, less work has been done to directly assess the extent to which specific tRNAs are misacylated in vivo, and the identity of the misacylated amino acid moiety. Here we describe tRNA isoacceptor specific aminoacylation profiling (ISAP), a method to identify and quantify the amino acids attached to a tRNA species in vivo. ISAP allows compilation of aminoacylation profiles for specific isoacceptors tRNAs. To demonstrate the efficacy and …


Maintenance Of Transcription-Translation Coupling By Elongation Factor P, Sara Elgamal, Irina Artsimovitch, Michael Ibba Sep 2016

Maintenance Of Transcription-Translation Coupling By Elongation Factor P, Sara Elgamal, Irina Artsimovitch, Michael Ibba

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Under conditions of tight coupling between translation and transcription, the ribosome enables synthesis of full-length mRNAs by preventing both formation of intrinsic terminator hairpins and loading of the transcription termination factor Rho. While previous studies have focused on transcription factors, we investigated the role of Escherichia coli elongation factor P (EF-P), an elongation factor required for efficient translation of mRNAs containing consecutive proline codons, in maintaining coupled translation and transcription. In the absence of EF-P, the presence of Rho utilization (rut) sites led to an ~30-fold decrease in translation of polyproline-encoding mRNAs. Coexpression of the Rho inhibitor Psu …


Stability And Kinetics Of Dna Pseudoknots: Formation Of T∗A•T Base-Triplets And Their Targeting Reactions, Calliste Steffensmeier Aug 2016

Stability And Kinetics Of Dna Pseudoknots: Formation Of T∗A•T Base-Triplets And Their Targeting Reactions, Calliste Steffensmeier

Theses & Dissertations

Pseudoknots have been found to play important roles in the biology of RNA. These stem-loop motifs are considered to be very compact and the targeting of their loops with complementary strands is accompanied with lower favorable free energy terms. We used a combination of spectroscopic (UV, CD and fluorescence), calorimetric (DSC, PPC and ITC) and kinetic (SPR) techniques to investigate: 1) Local base-triplet formation in pseudoknots; 2) energetic contributions for the association of pseudoknots with their complementary strands; and 3) the kinetic rates as a function of targeting strand length.

We investigated a set of DNA pseudoknots with sequence: d(TCTCT …


Assembly Of Nucleic Acid-Based Nanoparticles By Gas-Liquid Segmented Flow Microfluidics, Matthew L. Capek, Ross Verheul, David H. Thompson Aug 2016

Assembly Of Nucleic Acid-Based Nanoparticles By Gas-Liquid Segmented Flow Microfluidics, Matthew L. Capek, Ross Verheul, David H. Thompson

The Summer Undergraduate Research Fellowship (SURF) Symposium

The development of novel and efficient mixing methods is important for optimizing the efficiency of many biological and chemical processes. Tuning the physical and performance properties of nucleic acid-based nanoparticles is one such example known to be strongly affected by mixing efficiency. The characteristics of DNA nanoparticles (such as size, polydispersity, ζ-potential, and gel shift) are important to ensure their therapeutic potency, and new methods to optimize these characteristics are of significant importance to achieve the highest efficacy. In the present study, a simple segmented flow microfluidics system has been developed to augment mixing of pDNA/bPEI nanoparticles. This DNA and …


Analysis Of The Intricacies Of Substrate Recognition Of High Mobility Group Proteins And Aminoacyl-Trna Synthetases Using Non-Cognate Substrates, Douglas Van Iverson Ii Aug 2016

Analysis Of The Intricacies Of Substrate Recognition Of High Mobility Group Proteins And Aminoacyl-Trna Synthetases Using Non-Cognate Substrates, Douglas Van Iverson Ii

Dissertations

The studies presented in section 1 (Chapters I-IV) focus on the design and development of nucleic acid four-way junctions (4WJs) to target a member of the high mobility group (HMG) proteins, the proinflammatory cytokine high mobility group box 1 protein (HMGB1). In the present study, hybrid PNA-DNA 4WJs based on a model DNA 4WJ were constructed to improve the thermal stability of 4WJs while maintaining strong binding affinity toward HMGB1. An electrophoretic mobility shift assay (EMSA) was used to examine the binding affinity of an isolated DNA binding domain of HMGB1, the HMGB1 b-box (HMGB1b), toward a set of PNA-DNA …


Translation Control Of Swarming Proficiency In Bacillus Subtilis By 5-Amino-Pentanolylated Elongation Factor P, Andrei Rajkovic, Katherine R. Hummels, Anne Witzky, Sarah Erickson, Philip R. Gafken, Julian P. Whitelegge, Kym F. Faull, Daniel B. Kearns, Michael Ibba May 2016

Translation Control Of Swarming Proficiency In Bacillus Subtilis By 5-Amino-Pentanolylated Elongation Factor P, Andrei Rajkovic, Katherine R. Hummels, Anne Witzky, Sarah Erickson, Philip R. Gafken, Julian P. Whitelegge, Kym F. Faull, Daniel B. Kearns, Michael Ibba

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Elongation factor P (EF-P) accelerates diprolyl synthesis and requires a posttranslational modification to maintain proteostasis. Two phylogenetically distinct EF-P modification pathways have been described and are encoded in the majority of Gram-negative bacteria, but neither is present in Gram-positive bacteria. Prior work suggested that the EF-P-encoding gene (efp) primarily supports Bacillus subtilis swarming differentiation, whereas EF-P in Gram-negative bacteria has a more global housekeeping role, prompting our investigation to determine whether EF-P is modified and how it impacts gene expression in motile cells. We identified a 5-aminopentanol moiety attached to Lys32 of B. subtilis EF-P that is …