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Articles 1 - 30 of 238

Full-Text Articles in Biochemistry, Biophysics, and Structural Biology

Quantification Of Free Sialic Acid In Human Plasma Through A Robust Quinoxalinone Derivatization And Lc–Ms/Ms Using Isotope-Labeled Standard Calibration, Dan Wang, Xiang Zhou, Lin Wang, Sihe Wang, Xue-Long Sun Nov 2019

Quantification Of Free Sialic Acid In Human Plasma Through A Robust Quinoxalinone Derivatization And Lc–Ms/Ms Using Isotope-Labeled Standard Calibration, Dan Wang, Xiang Zhou, Lin Wang, Sihe Wang, Xue-Long Sun

Xue-Long Sun

We report an accurate quantification of free sialic acid (SA) in human plasma using LC–MS/MS method with isotope-labeled standard calibration (ILSC) and robust derivatization. Specifically, derivatization of SA with a stable and inexpensive 3,4-diaminotoluene (DAT) provides a stable product of SA with high MS response, proving a convenient and cost-effective LC–MS/MS analysis of free SA. In addition, the use of 13C3-SA as calibration standard ensured the accuracy for the measurement. This assay used ultra high performance liquid chromatography (UHPLC) for separation of native/labeled SA and IS from matrix interference, and employed ...


N-Glycosylation In The Protease Domain Of Trypsin-Like Serine Proteases Mediates Calnexin-Assisted Protein Folding, Hao Wang, Shuo Li, Juejin Wang, Shenghan Chen, Xue-Long Sun, Qingyu Wu Nov 2019

N-Glycosylation In The Protease Domain Of Trypsin-Like Serine Proteases Mediates Calnexin-Assisted Protein Folding, Hao Wang, Shuo Li, Juejin Wang, Shenghan Chen, Xue-Long Sun, Qingyu Wu

Xue-Long Sun

Trypsin-like serine proteases are essential in physiological processes. Studies have shown that N-glycans are important for serine protease expression and secretion, but the underlying mechanisms are poorly understood. Here, we report a common mechanism of N-glycosylation in the protease domains of corin, enteropeptidase and prothrombin in calnexin-mediated glycoprotein folding and extracellular expression. This mechanism, which is independent of calreticulin and operates in a domain-autonomous manner, involves two steps: direct calnexin binding to target proteins and subsequent calnexin binding to monoglucosylated N-glycans. Elimination of N-glycosylation sites in the protease domains of corin, enteropeptidase and prothrombin inhibits corin and enteropeptidase cell surface ...


Bsa–Boronic Acid Conjugate As Lectin Mimetics, Satya Nandana Narla, Poornima Pinnamaneni, Huan Nie, Yu Li, Xue-Long Sun Nov 2019

Bsa–Boronic Acid Conjugate As Lectin Mimetics, Satya Nandana Narla, Poornima Pinnamaneni, Huan Nie, Yu Li, Xue-Long Sun

Xue-Long Sun

We report bovine serum albumin (BSA)–boronic acid (BA) conjugates as lectin mimetics and their glyco-capturing capacity. The BSA–BA conjugates were synthesized by amidation of carboxylic acid groups in BSA with aminophenyl boronic acid in the presence of EDC, and were characterized by Alizarin Red S (ARS) assay and SDS–PAGE gel. The BSA–BA conjugates were immobilized onto maleimide-functionalized silica beads and their sugar capturing capacity and specificity were confirmed by ARS displacement assay. Further, surface plasmon resonance (SPR) analysis of the glyco-capturing activity of the BSA–BA conjugates was conducted by immobilizing BSA–BA onto SPR gold ...


Multi-Dimensional Glycan Microarrays With Glyco-Macroligands, Satya Nandana Narla, Huan Nie, Yu Li, Xue-Long Sun Nov 2019

Multi-Dimensional Glycan Microarrays With Glyco-Macroligands, Satya Nandana Narla, Huan Nie, Yu Li, Xue-Long Sun

Xue-Long Sun

Glycan microarray has become a powerful high-throughput tool for examining binding interactions of carbohydrates with the carbohydrate binding biomolecules like proteins, enzymes, antibodies etc. It has shown great potential for biomedical research and applications, such as antibody detection and profiling, vaccine development, biomarker discovery, and drug screening. Most glycan microarrays were made with monovalent glycans immobilized directly onto the array surface via either covalent or non-covalent bond, which afford a multivalent glycans in two dimensional (2D) displaying. A variety of glyco-macroligands have been developed to mimic multivalent carbohydrate-protein interactions for studying carbohydrate-protein interactions and biomedical research and applications. Recently, a ...


Theoretical Studies Of Ir And Nmr Spectral Changes Induced By Sigma-Hole Hydrogen, Halogen, Chalcogen, Pnicogen, And Tetrel Bonds In A Model Protein Environment, Mariusz Michalczyk, Wiktor Zierkiewicz, Rafał Wysokiński, Steve Scheiner Sep 2019

Theoretical Studies Of Ir And Nmr Spectral Changes Induced By Sigma-Hole Hydrogen, Halogen, Chalcogen, Pnicogen, And Tetrel Bonds In A Model Protein Environment, Mariusz Michalczyk, Wiktor Zierkiewicz, Rafał Wysokiński, Steve Scheiner

Steve Scheiner

Various types of σ-hole bond complexes were formed with FX, HFY, H2FZ, and H3FT (X = Cl, Br, I; Y = S, Se, Te; Z = P, As, Sb; T = Si, Ge, Sn) as Lewis acid. In order to examine their interactions with a protein, N-methylacetamide (NMA), a model of the peptide linkage was used as the base. These noncovalent bonds were compared by computational means with H-bonds formed by NMA with XH molecules (X = F, Cl, Br, I). In all cases, the A–F bond, which lies opposite the base and is responsible for the σ-hole on the ...


Synthesis And Evaluation Of Novel Silica Hydride-Based Stationary Phases For Bioanalytical Applications Sep 2019

Synthesis And Evaluation Of Novel Silica Hydride-Based Stationary Phases For Bioanalytical Applications

Seiichiro Watanabe

Most HPLC columns are packed with silanol (Si-OH)-rich type-B silica that often
participates in undesired electrostatic interactions with sample solutes and produces a poor analyte peak shape. These silanols are also known to facilitate the surface hydration required for HILIC mode to retain polar analytes. However, the hydrated surface composition can easily fluctuate, which results in poor reproducibility and requires a lengthy equilibration step. In this study, four novel stationary phases have been developed by using the TYPE-CTM silica material, in which up to 95% of the surface silanols have been replaced with Si-H group. One of the advantages ...


Metnet: Systems Biology Tools For Arabidopsis, Eve Syrkin Wurtele, Ling Li, Dan Berleant, Dianne Cook, Julie A. Dickerson, Jing Ding, Heike Hofmann, Michael Lawrence, Eun-Kyung Lee, Jie Li, Wieslawa Mentzen, Leslie Miller, Basil J. Nikolau, Nick Ransom, Yingjun Wang Sep 2019

Metnet: Systems Biology Tools For Arabidopsis, Eve Syrkin Wurtele, Ling Li, Dan Berleant, Dianne Cook, Julie A. Dickerson, Jing Ding, Heike Hofmann, Michael Lawrence, Eun-Kyung Lee, Jie Li, Wieslawa Mentzen, Leslie Miller, Basil J. Nikolau, Nick Ransom, Yingjun Wang

Eve Wurtele

MetNet (http://metnetdb.org) is an emerging open-source software platform for exploration of disparate experimental data types and regulatory and metabolic networks in the context of Arabidopsis systems biology. The MetNet platform features graph visualization, interactive displays, graph theoretic computations for determining biological distances, a unique multivariate display and statistical analysis tool, graph modeling using the open source statistical analysis language, R, and versatile text mining. The use of these tools is illustrated with data from the bio1 mutant of Arabidopsis.


Metnet: Systems Biology Tools For Arabidopsis, Eve Syrkin Wurtele, Ling Li, Dan Berleant, Dianne Cook, Julie A. Dickerson, Jing Ding, Heike Hofmann, Michael Lawrence, Eun-Kyung Lee, Jie Li, Wieslawa Mentzen, Leslie Miller, Basil J. Nikolau, Nick Ransom, Yingjun Wang Aug 2019

Metnet: Systems Biology Tools For Arabidopsis, Eve Syrkin Wurtele, Ling Li, Dan Berleant, Dianne Cook, Julie A. Dickerson, Jing Ding, Heike Hofmann, Michael Lawrence, Eun-Kyung Lee, Jie Li, Wieslawa Mentzen, Leslie Miller, Basil J. Nikolau, Nick Ransom, Yingjun Wang

Ling Li

MetNet (http://metnetdb.org) is an emerging open-source software platform for exploration of disparate experimental data types and regulatory and metabolic networks in the context of Arabidopsis systems biology. The MetNet platform features graph visualization, interactive displays, graph theoretic computations for determining biological distances, a unique multivariate display and statistical analysis tool, graph modeling using the open source statistical analysis language, R, and versatile text mining. The use of these tools is illustrated with data from the bio1 mutant of Arabidopsis.


A Systems Biology Approach Toward Understanding Seed Composition In Soybean, Ling Li, Manhoi Hur, Joon-Yong Lee, Wenxu Zhou, Zhihong Song, Nick Ransom, Cumhur Yusuf Demirkale, Daniel S. Nettleton, Mark E. Westgate, Zebulun Wayne Arendsee, Vidya Vaancheeswaran Iyer, Jacqueline V. Shanks, Basil Nikolau, Eve Wurtele Jun 2019

A Systems Biology Approach Toward Understanding Seed Composition In Soybean, Ling Li, Manhoi Hur, Joon-Yong Lee, Wenxu Zhou, Zhihong Song, Nick Ransom, Cumhur Yusuf Demirkale, Daniel S. Nettleton, Mark E. Westgate, Zebulun Wayne Arendsee, Vidya Vaancheeswaran Iyer, Jacqueline V. Shanks, Basil Nikolau, Eve Wurtele

Dan Nettleton

Background

The molecular, biochemical, and genetic mechanisms that regulate the complex metabolic network of soybean seed development determine the ultimate balance of protein, lipid, and carbohydrate stored in the mature seed. Many of the genes and metabolites that participate in seed metabolism are unknown or poorly defined; even more remains to be understood about the regulation of their metabolic networks. A global omics analysis can provide insights into the regulation of seed metabolism, even without a priori assumptions about the structure of these networks.

Results

With the future goal of predictive biology in mind, we have combined metabolomics, transcriptomics, and ...


Arca Controls Metabolism, Chemotaxis, And Motility Contributing To The Pathogenicity Of Avian Pathogenic Escherichia Coli, Fengwei Jiang, Chunxia An, Yinli Bao, Xuefeng Zhao, Robert L. Jernigan, Andrew Lithio, Dan Nettleton, Ling Li, Eve S. Wurtele, Lisa K. Nolan, Chengping Lu, Ganwu Li Jun 2019

Arca Controls Metabolism, Chemotaxis, And Motility Contributing To The Pathogenicity Of Avian Pathogenic Escherichia Coli, Fengwei Jiang, Chunxia An, Yinli Bao, Xuefeng Zhao, Robert L. Jernigan, Andrew Lithio, Dan Nettleton, Ling Li, Eve S. Wurtele, Lisa K. Nolan, Chengping Lu, Ganwu Li

Dan Nettleton

Avian pathogenic Escherichia coli (APEC) strains cause one of the three most significant infectious diseases in the poultry industry and are also potential food-borne pathogens threating human health. In this study, we showed that ArcA (aerobic respiratory control), a global regulator important for E. coli's adaptation from anaerobic to aerobic conditions and control of that bacterium's enzymatic defenses against reactive oxygen species (ROS), is involved in the virulence of APEC. Deletion of arcA significantly attenuates the virulence of APEC in the duck model. Transcriptome sequencing (RNA-Seq) analyses comparing the APEC wild type and the arcA mutant indicate that ...


Synthesis And Evaluation Of Novel Silica Hydride-Based Stationary Phases For Bioanalytical Application, Seiichiro Watanabe May 2019

Synthesis And Evaluation Of Novel Silica Hydride-Based Stationary Phases For Bioanalytical Application, Seiichiro Watanabe

Seiichiro Watanabe

Most HPLC columns are packed with silanol-rich (Si-OH) type-B silica material that often participates in undesired electrostatic interactions with the analyte solutes and produces poor peak shape [1,2]. These silanols are also known to facilitate surface hydration necessary for HILIC retention mode for polar analyte molecules. However, the hydrated surface composition can easily fluctuate, and thus results in a poor reproducibility and requires lengthy equilibration step. In this study, four novel stationary phases have been developed by using the TYPE-CTM Silica Hydride material, which has replaced up to 95% of the surface silanols with silicon-hydride (Si-H) groups. One of ...


Scale Up Isolation Of Aaptamine For In Vivo Evaluation Indicates Its Neurobiological Activity Is Linked To The Delta Opioid Receptor, Nicole L. Mcintosh, Eptisam Lambo, Laura Millan-Lobo, Fei Li, Li He, Phillip Crews, Jennifer L. Whistler, Tyler Johnson Mar 2019

Scale Up Isolation Of Aaptamine For In Vivo Evaluation Indicates Its Neurobiological Activity Is Linked To The Delta Opioid Receptor, Nicole L. Mcintosh, Eptisam Lambo, Laura Millan-Lobo, Fei Li, Li He, Phillip Crews, Jennifer L. Whistler, Tyler Johnson

Tyler Johnson

Opioid receptors belong to the large superfamily of seven transmembrane-spanning (7TM) G protein-coupled receptors (GPCRs). As a class, GPCRs are of fundamental physiological importance mediating the actions of the majority of known neurotransmitters and hormones. The Mu, Delta, and Kappa (MOP, DOP, KOP) opioid receptors are particularly intriguing members of this receptor family as they are the targets involved in many neurobiological diseases such as addiction, pain, stress, anxiety, and depression. Recently we discovered that the aaptamine class of marine sponge derived natural products exhibit selective agonist activity in vitro for the DOP versus MOP receptor. Our findings may explain ...


Generating High-Order Optical And Spin Harmonics From Ferromagnetic Monolayers, G.P. Zhang, M.S. Si, M. Murakami, Y.H. Bai, Thomas F. George Nov 2018

Generating High-Order Optical And Spin Harmonics From Ferromagnetic Monolayers, G.P. Zhang, M.S. Si, M. Murakami, Y.H. Bai, Thomas F. George

Thomas George

High-order harmonic generation (HHG) in solids has entered a new phase of intensive research, with envisioned band-structure mapping on an ultrashort time scale. This partly benefits from a flurry of new HHG materials discovered, but so far has missed an important group. HHG in magnetic materials should have profound impact on future magnetic storage technology advances. Here we introduce and demonstrate HHG in ferromagnetic monolayers. We find that HHG carries spin information and sensitively depends on the relativistic spin–orbit coupling; and if they are dispersed into the crystal momentum k space, harmonics originating from real transitions can be k-resolved ...


Spatial Mapping And Profiling Of Metabolite Distributions During Germination, Adam D. Feenstra, Liza E. Alexander, Zhihong Song, Andrew R. Korte, Marna D. Yandeau-Nelson, Basil J. Nikolau, Young-Jin Lee Nov 2018

Spatial Mapping And Profiling Of Metabolite Distributions During Germination, Adam D. Feenstra, Liza E. Alexander, Zhihong Song, Andrew R. Korte, Marna D. Yandeau-Nelson, Basil J. Nikolau, Young-Jin Lee

Robbyn Anand

Germination is a highly complex process by which seeds begin to develop and establish themselves as viable organisms. In this paper, we utilize a combination of GC-MS, LC-fluorescence, and mass spectrometry imaging (MSI) approaches to profile and visualize the metabolic distributions of germinating seeds from two different inbreds of maize seeds, B73 and Mo17. GC and LC analyses demonstrate that the two inbreds are highly differentiated in their metabolite profiles throughout the course of germination, especially with regard to amino acids, sugar alcohols, and small organic acids. Crude dissection of the seed followed by GC-MS analysis of polar metabolites also ...


Conjugation Of Nanomaterials And Nematic Liquid Crystals For Futuristic Applications And Biosensors, Thomas F. George, Amit Choudhary, Guoqiang Li Jul 2018

Conjugation Of Nanomaterials And Nematic Liquid Crystals For Futuristic Applications And Biosensors, Thomas F. George, Amit Choudhary, Guoqiang Li

Thomas George

The established role of nematic liquid crystals (NLCs) in the recent rapid development of displays has motivated researchers to modulate the electro-optical properties of LCs. Furthermore, adding nanomaterials into NLCs has led to enhancements of the properties of NLCs, like reduced threshold of the operating voltage, variation in pretilt angle, reduced switching time, etc. These enhanced properties, due to interfacial dynamics, are enabling wider applications of NLCs and nanomaterials. The recent literature of nanomaterial-doped NLCs is rich with various kinds of nanomaterials in a variety of NLCs. The light has been focused on the most widely used and studied gold ...


The Dual Regulatory Role Of Amino Acids Leu480 And Gln481 Of Prothrombin, Joesph R. Wiencek, Jamila Hirbawi, Vivien C. Yee, Michael Kalafatis May 2018

The Dual Regulatory Role Of Amino Acids Leu480 And Gln481 Of Prothrombin, Joesph R. Wiencek, Jamila Hirbawi, Vivien C. Yee, Michael Kalafatis

Michael Kalafatis

Prothrombin (FII) is activated to α-thrombin (IIa) by prothrombinase. Prothrombinase is composed of a catalytic subunit, factor Xa (fXa), and a regulatory subunit, factor Va (fVa), assembled on a membrane surface in the presence of divalent metal ions. We constructed, expressed, and purified several mutated recombinant FII (rFII) molecules within the previously determined fVa-dependent binding site for fXa (amino acid region 473–487 of FII). rFII molecules bearing overlapping deletions within this significant region first established the minimal stretch of amino acids required for the fVa-dependent recognition exosite for fXa in prothrombinase within the amino acid sequence Ser478–Val ...


Shaping Light In Backward-Wave Nonlinear Hyperbolic Metamaterials, Thomas F. George, Alexander K. Popov, Sergey A. Myslivets, Vitaly V. Slabko, Victor A. Tkachenko Apr 2018

Shaping Light In Backward-Wave Nonlinear Hyperbolic Metamaterials, Thomas F. George, Alexander K. Popov, Sergey A. Myslivets, Vitaly V. Slabko, Victor A. Tkachenko

Thomas George

Backward electromagnetic waves are extraordinary waves with contra-directed phase velocity and energy flux. Unusual properties of the coherent nonlinear optical coupling of the phase-matched ordinary and backward electromagnetic waves with contra-directed energy fluxes are described that enable greatly-enhanced frequency and propagation direction conversion, parametrical amplification, as well as control of shape of the light pulses. Extraordinary transient processes that emerge in such metamaterials in pulsed regimes are described. The results of the numerical simulation of particular plasmonic metamaterials with hyperbolic dispersion are presented, which prove the possibility to match phases of such coupled guided ordinary and backward electromagnetic waves. Particular ...


Modification Of Purine And Pyrimidine Nucleosides By Direct C-H Bond Activation, Yong Liang, Stanislaw F. Wnuk Apr 2018

Modification Of Purine And Pyrimidine Nucleosides By Direct C-H Bond Activation, Yong Liang, Stanislaw F. Wnuk

Stanislaw Wnuk

Transition metal-catalyzed modifications of the activated heterocyclic bases of nucleosides as well as DNA or RNA fragments employing traditional cross-coupling methods have been well-established in nucleic acid chemistry. This review covers advances in the area of cross-coupling reactions in which nucleosides are functionalized via direct activation of the C8-H bond in purine and the C5-H or C6-H bond in uracil bases. The review focuses on Pd/Cu-catalyzed couplings between unactivated nucleoside bases with aryl halides. It also discusses cross-dehydrogenative arylations and alkenylations as well as other reactions used for modification of nucleoside bases that avoid the use of organometallic precursors ...


Lysine Biosynthesis In Bacteria: A Metallodesuccinylase As A Potential Antimicrobial Target, Danuta M. Gillner, Daniel P. Becker Ph.D., Richard C. Holz Feb 2018

Lysine Biosynthesis In Bacteria: A Metallodesuccinylase As A Potential Antimicrobial Target, Danuta M. Gillner, Daniel P. Becker Ph.D., Richard C. Holz

Richard C. Holz

In this review, we summarize the recent literature on dapE-encoded N-succinyl-l,l-diaminopimelic acid desuccinylase (DapE) enzymes, with an emphasis on structure–function studies that provide insight into the catalytic mechanism. Crystallographic data have also provided insight into residues that might be involved in substrate and hence inhibitor recognition and binding. These data have led to the design and synthesis of several new DapE inhibitors, which are described along with what is known about how inhibitors interact with the active site of DapE enzymes, including the efficacy of a moderately strong DapE inhibitor.


The Structure And Function Of Small Nucleolar Ribonucleoproteins, Steve Reichow, Tomoko Hamma, Adrian R. Ferré-D’Amaré, Gabriele Varani Oct 2017

The Structure And Function Of Small Nucleolar Ribonucleoproteins, Steve Reichow, Tomoko Hamma, Adrian R. Ferré-D’Amaré, Gabriele Varani

Steve Reichow

Eukaryotes and archaea use two sets of specialized ribonucleoproteins (RNPs) to carry out sequencespecific methylation and pseudouridylation of RNA, the two most abundant types of modifications of cellular RNAs. In eukaryotes, these protein–RNA complexes localize to the nucleolus and are called small nucleolar RNPs (snoRNPs), while in archaea they are known as small RNPs (sRNP). The C/D class of sno(s)RNPs carries out ribose- 20-O-methylation, while the H/ACA class is responsible for pseudouridylation of their RNA targets. Here, we review the recent advances in the structure, assembly and function of the conserved C/D and H ...


Tension Directly Stabilizes Reconstituted Kinetochore-Microtubule Attachments, Bungo Akiyoshi, Krishna K. Sarangapani, Andrew F. Powers, Christian R. Nelson, Steve Reichow, Hugo Arellano-Santoyo, Tamir Gonen, Jeffrey A. Ranish, Charles L. Asbury, Sue Biggins Oct 2017

Tension Directly Stabilizes Reconstituted Kinetochore-Microtubule Attachments, Bungo Akiyoshi, Krishna K. Sarangapani, Andrew F. Powers, Christian R. Nelson, Steve Reichow, Hugo Arellano-Santoyo, Tamir Gonen, Jeffrey A. Ranish, Charles L. Asbury, Sue Biggins

Steve Reichow

Kinetochores are macromolecular machines that couple chromosomes to dynamic microtubule tips during cell division, thereby generating force to segregate the chromosomes. Accurate segregation depends on selective stabilization of correct ‘bi-oriented’ kinetochore-microtubule attachments, which come under tension due to opposing forces exerted by microtubules. Tension is thought to stabilize these bi-oriented attachments indirectly, by suppressing the destabilizing activity of a kinase, Aurora B. However, a complete mechanistic understanding of the role of tension requires reconstitution of kinetochore-microtubule attachments for biochemical and biophysical analyses in vitro. Here we show that native kinetochore particles retaining the majority of kinetochore proteins can be purified ...


Lipid-Protein Interactions Probed By Electron Crystallography, Steve L. Reichow, Tamir Gonen Oct 2017

Lipid-Protein Interactions Probed By Electron Crystallography, Steve L. Reichow, Tamir Gonen

Steve Reichow

Electron crystallography is arguably the only electron cryomicroscopy (cryoEM) technique able to deliver an atomic-resolution structure of membrane proteins embedded in the lipid-bilayer. In the electron crystallographic structures of the light driven ion pump, bacteriorhodopsin, and the water channel, aquaporin-0, sufficiently high resolution was obtained and both lipid and protein were visualized, modeled and described in detail. An extensive network of lipid-protein interactions mimicking native membranes is established and maintained in two-dimensional (2D) crystalline vesicles used for structural analysis by electron crystallography. Lipids are tightly integrated into the protein's architecture where they can affect the function, structure, quaternary assembly ...


Electron Crystallography Of Aquaporins, Simeon Andrews, Steve Reichow, Tamir Gonen Oct 2017

Electron Crystallography Of Aquaporins, Simeon Andrews, Steve Reichow, Tamir Gonen

Steve Reichow

Aquaporins are a family of ubiquitous membrane proteins that form a pore for the permeation of water. Both electron and X-ray crystallography played major roles in determining the atomic structures of a number of aquaporins. This review focuses on electron crystallography, and its contribution to the field of aquaporin biology. We briefly discuss electron crystallography and the two-dimensional crystallization process. We describe features of aquaporins common to both electron and X-ray crystallographic structures; as well as some structural insights unique to electron crystallography, including aquaporin junction formation and lipid-protein interactions.


Cooperative Interaction Of Transcription Termination Factors With The Rna Polymerase Ii C-Terminal Domain, Bradley M. Lunde, Steve Reichow, Minkyu Kim, Hyunsuk Suh, Thomas C. Leeper, Fan Yang, Hannes Mutschler, Stephen Buratowski, Anton Meinhart, Gabriele Varani Oct 2017

Cooperative Interaction Of Transcription Termination Factors With The Rna Polymerase Ii C-Terminal Domain, Bradley M. Lunde, Steve Reichow, Minkyu Kim, Hyunsuk Suh, Thomas C. Leeper, Fan Yang, Hannes Mutschler, Stephen Buratowski, Anton Meinhart, Gabriele Varani

Steve Reichow

Phosphorylation of the C-terminal domain of RNA polymerase II controls the co-transcriptional assembly of RNA processing and transcription factors. Recruitment relies on conserved CTDinteracting domains that recognize different CTD phosphoisoforms during the transcription cycle, but the molecular basis for their specificity remains unclear. We show that the CTD-interacting domains of two transcription termination factors, Rtt103 and Pcf11, achieve high affinity and specificity both by specifically recognizing the phosphorylated CTD and by cooperatively binding to neighboring CTD repeats. Single amino acid mutations at the protein-protein interface abolish cooperativity and affect recruitment at the 3′-end processing site in vivo. We suggest ...


First-Principles And Model Simulation Of All-Optical Spin Reversal, Thomas F. George, G.P. Zhang, Z. Babyak, Y. Xue, Y. H. Bai Oct 2017

First-Principles And Model Simulation Of All-Optical Spin Reversal, Thomas F. George, G.P. Zhang, Z. Babyak, Y. Xue, Y. H. Bai

Thomas George

All-optical spin switching is a potential trailblazer for information storage and communication at an unprecedented fast rate free of magnetic fields. However, the current wisdom is largely based on semiempirical models of effective magnetic fields and heat pulses, so it is difficult to provide high-speed design protocols for actual devices. Here, we carry out a massively parallel first-principles and model calculation for 13 spin systems and magnetic layers, free of any effective field, to establish a simpler and alternative paradigm of laser-induced ultrafast spin reversal and to point out a path to a full-integrated photospintronic device. It is the interplay ...


Biophysical And Computational Studies Of The Vcci:Vmip-Ii Complex, Anna Nguyen, Nai-Wei Kuo, Laura Showalter, Ricardo Ramos, Cynthia Dupureur, Michael Colvin, Patricia Liwang Aug 2017

Biophysical And Computational Studies Of The Vcci:Vmip-Ii Complex, Anna Nguyen, Nai-Wei Kuo, Laura Showalter, Ricardo Ramos, Cynthia Dupureur, Michael Colvin, Patricia Liwang

Cynthia Dupureur

Certain viruses have the ability to subvert the mammalian immune response, including interference in the chemokine system. Poxviruses produce the chemokine binding protein vCCI (viral CC chemokine inhibitor; also called 35K), which tightly binds to CC chemokines. To facilitate the study of vCCI, we first provide a protocol to produce folded vCCI from Escherichia coli (E. coli.) It is shown here that vCCI binds with unusually high affinity to viral Macrophage Inflammatory Protein-II (vMIP-II), a chemokine analog produced by the virus, human herpesvirus 8 (HHV-8). Fluorescence anisotropy was used to investigate the vCCI:vMIP-II complex and shows that vCCI binds ...


Qqs Orphan Gene Regulates Carbon And Nitrogen Partitioning Across Species Via Nf-Yc Interactions, Ling Li, Wenguang Zheng, Yanbing Zhu, Huaxun Ye, Buyun Tang, Zebulun W. Arendsee, Dallas Jones, Ruoran Li, Diego Ortiz, Xuefeng Zhao, Chuanlong Du, Dan Nettleton, M. Paul Scott, Maria G. Salas-Fernandez, Yanhai Yin, Eve S. Wurtele Aug 2017

Qqs Orphan Gene Regulates Carbon And Nitrogen Partitioning Across Species Via Nf-Yc Interactions, Ling Li, Wenguang Zheng, Yanbing Zhu, Huaxun Ye, Buyun Tang, Zebulun W. Arendsee, Dallas Jones, Ruoran Li, Diego Ortiz, Xuefeng Zhao, Chuanlong Du, Dan Nettleton, M. Paul Scott, Maria G. Salas-Fernandez, Yanhai Yin, Eve S. Wurtele

Ling Li

The allocation of carbon and nitrogen resources to the synthesis of plant proteins, carbohydrates, and lipids is complex and under the control of many genes; much remains to be understood about this process. QQS (Qua-Quine Starch; At3g30720), an orphan gene unique to Arabidopsis thaliana, regulates metabolic processes affecting carbon and nitrogen partitioning among proteins and carbohydrates, modulating leaf and seed composition in Arabidopsis and soybean. Here the universality of QQS function in modulating carbon and nitrogen allocation is exemplified by a series of transgenic experiments. We show that ectopic expression of QQS increases soybean protein independent of the genetic background ...


Arca Controls Metabolism, Chemotaxis, And Motility Contributing To The Pathogenicity Of Avian Pathogenic Escherichia Coli, Fengwei Jiang, Chunxia An, Yinli Bao, Xuefeng Zhao, Robert L. Jernigan, Andrew Lithio, Dan Nettleton, Ling Li, Eve S. Wurtele, Lisa K. Nolan, Chengping Lu, Ganwu Li Aug 2017

Arca Controls Metabolism, Chemotaxis, And Motility Contributing To The Pathogenicity Of Avian Pathogenic Escherichia Coli, Fengwei Jiang, Chunxia An, Yinli Bao, Xuefeng Zhao, Robert L. Jernigan, Andrew Lithio, Dan Nettleton, Ling Li, Eve S. Wurtele, Lisa K. Nolan, Chengping Lu, Ganwu Li

Ling Li

Avian pathogenic Escherichia coli (APEC) strains cause one of the three most significant infectious diseases in the poultry industry and are also potential food-borne pathogens threating human health. In this study, we showed that ArcA (aerobic respiratory control), a global regulator important for E. coli's adaptation from anaerobic to aerobic conditions and control of that bacterium's enzymatic defenses against reactive oxygen species (ROS), is involved in the virulence of APEC. Deletion of arcA significantly attenuates the virulence of APEC in the duck model. Transcriptome sequencing (RNA-Seq) analyses comparing the APEC wild type and the arcA mutant indicate that ...


A Systems Biology Approach Toward Understanding Seed Composition In Soybean, Ling Li, Manhoi Hur, Joon-Yong Lee, Wenxu Zhou, Zhihong Song, Nick Ransom, Cumhur Yusuf Demirkale, Daniel S. Nettleton, Mark E. Westgate, Zebulun Wayne Arendsee, Vidya Vaancheeswaran Iyer, Jacqueline V. Shanks, Basil Nikolau, Eve Wurtele Aug 2017

A Systems Biology Approach Toward Understanding Seed Composition In Soybean, Ling Li, Manhoi Hur, Joon-Yong Lee, Wenxu Zhou, Zhihong Song, Nick Ransom, Cumhur Yusuf Demirkale, Daniel S. Nettleton, Mark E. Westgate, Zebulun Wayne Arendsee, Vidya Vaancheeswaran Iyer, Jacqueline V. Shanks, Basil Nikolau, Eve Wurtele

Ling Li

Background

The molecular, biochemical, and genetic mechanisms that regulate the complex metabolic network of soybean seed development determine the ultimate balance of protein, lipid, and carbohydrate stored in the mature seed. Many of the genes and metabolites that participate in seed metabolism are unknown or poorly defined; even more remains to be understood about the regulation of their metabolic networks. A global omics analysis can provide insights into the regulation of seed metabolism, even without a priori assumptions about the structure of these networks.

Results

With the future goal of predictive biology in mind, we have combined metabolomics, transcriptomics, and ...


Dengue Virus Ns2b/Ns3 Protease Inhibitors Exploiting The Prime Side, Kuan-Hung Lin, Akbar Ali, Linah Rusere, Djade I. Soumana, Nese Kurt Yilmaz, Celia A. Schiffer Jul 2017

Dengue Virus Ns2b/Ns3 Protease Inhibitors Exploiting The Prime Side, Kuan-Hung Lin, Akbar Ali, Linah Rusere, Djade I. Soumana, Nese Kurt Yilmaz, Celia A. Schiffer

Celia A. Schiffer

The mosquito-transmitted dengue virus (DENV) infects millions of people in tropical and subtropical regions. Maturation of DENV particles requires proper cleavage of the viral polyprotein, including processing of 8 of the 13 substrate cleavage sites by dengue virus NS2B/NS3 protease. With no available direct-acting antiviral targeting DENV, NS2/NS3 protease is a promising target for inhibitor design. Current design efforts focus on the nonprime side of the DENV protease active site, resulting in highly hydrophilic and nonspecific scaffolds. However, the prime side also significantly modulates DENV protease binding affinity, as revealed by engineering the binding loop of aprotinin, a ...