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Cognative maps

Graham S Erwin, Matthew P Grieshop, Devesh Bhimsaria, Truman J Do, José A Rodríguez-Martínez, Charu Mehta, Kanika Khanna, Scott A Swanson, Ron Stewart, James A Thomson, Parameswaran Ramanathan, Aseem Z Ansari
Targeting the genome with sequence-specific DNA-binding molecules is a major goal at the interface of chemistry, biology, and precision medicine. Polyamides, composed of N-methylpyrrole and N-methylimidazole monomers, are a class of synthetic molecules that can be rationally designed to "read" specific DNA sequences. However, the impact of different chromatin states on polyamide binding in live cells remains an unresolved question that impedes their deployment in vivo. Here, we use cross-linking of small molecules to isolate chromatin coupled to sequencing to map the binding of two bioactive and structurally distinct polyamides to genomes directly within live H1 human embryonic stem cells...
November 8, 2016: Proceedings of the National Academy of Sciences of the United States of America
David Alsteens, Richard Newton, Rajib Schubert, David Martinez-Martin, Martin Delguste, Botond Roska, Daniel J Müller
Viral infection is initiated when a virus binds to cell surface receptors. Because the cell membrane is dynamic and heterogeneous, imaging living cells and simultaneously quantifying the first viral binding events is difficult. Here, we show an atomic force and confocal microscopy set-up that allows the surface receptor landscape of cells to be imaged and the virus binding events within the first millisecond of contact with the cell to be mapped at high resolution (<50 nm). We present theoretical approaches to contour the free-energy landscape of early binding events between an engineered virus and cell surface receptors...
October 31, 2016: Nature Nanotechnology
Yu Okubo, Hiroaki Uchida, Aika Wakata, Takuma Suzuki, Tomoko Shibata, Hitomi Ikeda, Miki Yamaguchi, Justus B Cohen, Joseph C Glorioso, Mitsuo Tagaya, Hirofumi Hamada, Hideaki Tahara
: Membrane fusion, which is the key process for both initial cell entry and subsequent lateral spread of herpes simplex virus (HSV), requires the four envelope glycoproteins gB, gD, gH, and gL. Syncytial mutations, predominantly mapped to the gB and gK genes, confer hyperfusogenicity on HSV and cause multinucleated giant cells, termed syncytia. Here, we asked whether interaction of gD with a cognate entry receptor remains indispensable for initiating membrane fusion of syncytial strains...
October 5, 2016: Journal of Virology
Fanny Sunden, Ishraq AlSadhan, Artem Y Lyubimov, Susanne Ressl, Helen Wiersma-Koch, Jamar Borland, Clayton L Brown, Tory A Johnson, Zorawar Singh, Daniel Herschlag
Naively one might have expected an early division between phosphate monoesterases and diesterases of the alkaline phosphatase (AP) superfamily. On the contrary, prior results and our structural and biochemical analyses of phosphate monoesterase PafA, from Chryseobacterium meningosepticum, indicate similarities to a superfamily phosphate diesterase [Xanthomonas citri nucleotide pyrophosphatase/phosphodiesterase (NPP)] and distinct differences from the three metal ion AP superfamily monoesterase, from Escherichia coli AP (EcAP)...
November 2, 2016: Journal of the American Chemical Society
Marco-Antonio Mendoza-Parra, Valeriya Malysheva, Mohamed Ashick Mohamed Saleem, Michele Lieb, Aurelie Godel, Hinrich Gronemeyer
Cell lineages, which shape the body architecture and specify cell functions, derive from the integration of a plethora of cell intrinsic and extrinsic signals. These signals trigger a multiplicity of decisions at several levels to modulate the activity of dynamic gene regulatory networks (GRNs), which ensure both general and cell-specific functions within a given lineage, thereby establishing cell fates. Significant knowledge about these events and the involved key drivers comes from homogeneous cell differentiation models...
November 2016: Genome Research
Lyndsey M Muehling, Duy T Mai, William W Kwok, Peter W Heymann, Anna Pomés, Judith A Woodfolk
Rhinovirus (RV) is a major cause of common cold and an important trigger of acute episodes of chronic lung diseases. Antigenic variation across the numerous RV strains results in frequent infections and a lack of durable cross-protection. Because the nature of human CD4(+) T cells that target RV is largely unknown, T cell epitopes of RV capsid proteins were analyzed, and cognate T cells were characterized in healthy subjects and those infected by intranasal challenge. Peptide epitopes of the RV-A16 capsid proteins VP1 and VP2 were identified by peptide/MHC class II tetramer-guided epitope mapping, validated by direct ex vivo enumeration, and interrogated using a variety of in silico methods...
October 15, 2016: Journal of Immunology: Official Journal of the American Association of Immunologists
Julia Babski, Karina A Haas, Daniela Näther-Schindler, Friedhelm Pfeiffer, Konrad U Förstner, Matthias Hammelmann, Rolf Hilker, Anke Becker, Cynthia M Sharma, Anita Marchfelder, Jörg Soppa
BACKGROUND: Differential RNA-Seq (dRNA-Seq) is a recently developed method of performing primary transcriptome analyses that allows for the genome-wide mapping of transcriptional start sites (TSSs) and the identification of novel transcripts. Although the transcriptomes of diverse bacterial species have been characterized by dRNA-Seq, the transcriptome analysis of archaeal species is still rather limited. Therefore, we used dRNA-Seq to characterize the primary transcriptome of the model archaeon Haloferax volcanii...
2016: BMC Genomics
Marina Casiraghi, Marjorie Damian, Ewen Lescop, Elodie Point, Karine Moncoq, Nelly Morellet, Daniel Levy, Jacky Marie, Eric Guittet, Jean-Louis Banères, Laurent J Catoire
Mapping the conformational landscape of G protein-coupled receptors (GPCRs), and in particular how this landscape is modulated by the membrane environment, is required to gain a clear picture of how signaling proceeds. To this end, we have developed an original strategy based on solution-state nuclear magnetic resonance combined with an efficient isotope labeling scheme. This strategy was applied to a typical GPCR, the leukotriene B4 receptor BLT2, reconstituted in a lipid bilayer. Because of this, we are able to provide direct evidence that BLT2 explores a complex landscape that includes four different conformational states for the unliganded receptor...
September 7, 2016: Journal of the American Chemical Society
Hiroki Kanazawa, Md Mominul Hoque, Masaru Tsunoda, Kaoru Suzuki, Tamotsu Yamamoto, Gota Kawai, Jiro Kondo, Akio Takénaka
D-3-Hydroxybutyrate dehydrogenase catalyzes the reversible conversion of acetoacetate and D-3-hydroxybutyrate. These ketone bodies are both energy-storage forms of acetyl-CoA. In order to clarify the structural mechanisms of the catalytic reaction with the cognate substrate D-3-hydroxybutyrate and of the inhibition of the reaction by inhibitors, the enzyme from Alcaligenes faecalis has been analyzed by X-ray crystallography in liganded states with the substrate and with two types of inhibitor: malonate and methylmalonate...
July 2016: Acta Crystallographica. Section F, Structural Biology Communications
Rebecca C Wilson, Oliver W Butters, Tom Clark, Joel Minion, Andrew Turner, Madeleine J Murtagh
ECOUTER (Employing COnceptUal schema for policy and Translation Engagement in Research) - French for 'to listen' - is a new stakeholder engagement method incorporating existing evidence to help participants draw upon their own knowledge of cognate issues and interact on a topic of shared concern. The results of an ECOUTER can form the basis of recommendations for research, governance, practice and/or policy. This paper describes the development of a digital methodology for the ECOUTER engagement process based on currently available mind mapping freeware software...
2016: F1000Research
Xiao-Ou Zhang, Rui Dong, Yang Zhang, Jia-Lin Zhang, Zheng Luo, Jun Zhang, Ling-Ling Chen, Li Yang
Circular RNAs (circRNAs) derived from back-spliced exons have been widely identified as being co-expressed with their linear counterparts. A single gene locus can produce multiple circRNAs through alternative back-splice site selection and/or alternative splice site selection; however, a detailed map of alternative back-splicing/splicing in circRNAs is lacking. Here, with the upgraded CIRCexplorer2 pipeline, we systematically annotated different types of alternative back-splicing and alternative splicing events in circRNAs from various cell lines...
September 2016: Genome Research
Geneviève Desjardins, Mark Okon, Barbara J Graves, Lawrence P McIntosh
The affinity of the Ets-1 transcription factor for DNA is autoinhibited by an intrinsically disordered serine-rich region (SRR) and a helical inhibitory module (IM) appended to its winged helix-turn-helix ETS domain. Using NMR spectroscopy, we investigated how Ets-1 recognizes specific versus nonspecific DNA, with a focus on the roles of protein dynamics and autoinhibition in these processes. Upon binding either DNA, the two marginally stable N-terminal helices of the IM predominantly unfold, but still sample partially ordered conformations...
July 26, 2016: Biochemistry
Simon Rousseau, Guy Martel
Lymphoid neoplasms form a family of cancers affecting B-cells, T-cells, and NK cells. The Toll-Like Receptor (TLR) signaling adapter molecule MYD88 is the most frequently mutated gene in these neoplasms. This signaling adaptor relays signals from TLRs to downstream effector pathways such as the Nuclear Factor kappa B (NFκB) and Mitogen Activated Protein Kinase (MAPK) pathways to regulate innate immune responses. Gain-of-function mutations such as MYD88[L265P] activate downstream signaling pathways in absence of cognate ligands for TLRs, resulting in increased cellular proliferation and survival...
2016: Frontiers in Cell and Developmental Biology
Mohsin Sarwar, Xiao-Jun Du, Thomas B Dschietzig, Roger J Summers
The insulin-like peptide relaxin, originally identified as a hormone of pregnancy, is now known to exert a range of pleiotropic effects including vasodilatory, anti-fibrotic, angiogenic, anti-apoptotic and anti-inflammatory effects in both males and females. Relaxin produces these effects by binding to a cognate receptor RXFP1 and activating a variety of signalling pathways including cAMP, cGMP and MAPKs as well as by altering gene expression of TGF-β, MMPs, angiogenic growth factors and endothelin receptors...
May 30, 2016: British Journal of Pharmacology
Akio Fukumori, Harald Steiner
Intramembrane proteases execute fundamental biological processes ranging from crucial signaling events to general membrane proteostasis. Despite the availability of structural information on these proteases, it remains unclear how these enzymes bind and recruit substrates, particularly for the Alzheimer's disease-associated γ-secretase. Systematically scanning amyloid precursor protein substrates containing a genetically inserted photocrosslinkable amino acid for binding to γ-secretase allowed us to identify residues contacting the protease...
August 1, 2016: EMBO Journal
Yanjun Kou, Naweed I Naqvi
Pathogenic fungi have evolved highly varied and remarkable strategies to invade and infect their plant hosts. Typically, such fungal pathogens utilize highly specialized infection structures, morphologies or cell types produced from conidia or ascospores on the cognate host surfaces to gain entry therein. Such diverse infection strategies require intricate coordination in cell signaling and differentiation in phytopathogenic fungi. Here, we present an overview of our current understanding of cell signaling and infection-associated development that primes host penetration in the top ten plant pathogenic fungi, which utilize specific receptors to sense and respond to different surface cues, such as topographic features, hydrophobicity, hardness, plant lipids, phytohormones, and/or secreted enzymes...
September 2016: Seminars in Cell & Developmental Biology
Stefan Sulmann, Melanie Wallisch, Alexander Scholten, Jens Christoffers, Karl-Wilhelm Koch
Myristoylation of most neuronal calcium sensor proteins, a group of EF-hand calcium-binding proteins mainly expressed in neuronal tissue, can have a strong impact on protein dynamics and functional properties. Intracellular oscillations of the free Ca(2+) concentration can trigger conformational changes in Ca(2+) sensors. The position and possible movements of the myristoyl group in the photoreceptor cell-specific Ca(2+) sensor GCAP2 are not well-defined but appear to be different from those of the highly homologous cognate GCAP1...
May 10, 2016: Biochemistry
Chris A Brackley, James Johnson, Steven Kelly, Peter R Cook, Davide Marenduzzo
Biophysicists are modeling conformations of interphase chromosomes, often basing the strengths of interactions between segments distant on the genetic map on contact frequencies determined experimentally. Here, instead, we develop a fitting-free, minimal model: bivalent or multivalent red and green 'transcription factors' bind to cognate sites in strings of beads ('chromatin') to form molecular bridges stabilizing loops. In the absence of additional explicit forces, molecular dynamic simulations reveal that bound factors spontaneously cluster-red with red, green with green, but rarely red with green-to give structures reminiscent of transcription factories...
May 5, 2016: Nucleic Acids Research
Sabine Rauth, Dominik Hinz, Michael Börger, Markus Uhrig, Manuel Mayhaus, Matthias Riemenschneider, Arne Skerra
Amyloid beta (Aβ) peptides, in particular Aβ42 and Aβ40, exert neurotoxic effects and their overproduction leads to amyloid deposits in the brain, thus constituting an important biomolecular target for treatments of Alzheimer's disease (AD). We describe the engineering of cognate Anticalins as a novel type of neutralizing protein reagent based on the human lipocalin scaffold. Phage display selection from a genetic random library comprising variants of the human lipocalin 2 (Lcn2) with mutations targeted at 20 exposed amino acid positions in the four loops that form the natural binding site was performed using both recombinant and synthetic target peptides and resulted in three different Anticalins...
June 1, 2016: Biochemical Journal
Patrick Hörnschemeyer, Viktoria Liss, Ralf Heermann, Kirsten Jung, Sabine Hunke
Two-component systems are the major means by which bacteria couple adaptation to environmental changes. All utilize a phosphorylation cascade from a histidine kinase to a response regulator, and some also employ an accessory protein. The system-wide signaling fidelity of two-component systems is based on preferential binding between the signaling proteins. However, information on the interaction kinetics between membrane embedded histidine kinase and its partner proteins is lacking. Here, we report the first analysis of the interactions between the full-length membrane-bound histidine kinase CpxA, which was reconstituted in nanodiscs, and its cognate response regulator CpxR and accessory protein CpxP...
2016: PloS One
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