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Tethering complex

Andreas Gravvanis, Despoina Kakagia, Nick Katsikeris, Dimosthenis Tsoutsos
BACKGROUND: This report aims to first present Integra as an adjunct to complex mandibular reconstruction for intraoral lining resurfacing, and to review the literature on the use of dermal matrices for mucosal resurfacing of the floor of the mouth. CLINICAL REPORT: A 62-year-old female patient with previous ablation surgery for squamous cell carcinoma of the floor of the mouth, presented with extrusion of the mandibular plate through the chin skin and serious tongue tethering...
October 2016: Journal of Craniofacial Surgery
Peng Wei Zhu, Luguang Chen
A persistence length is a key parameter for the quantitative interpretation of the flexibility of polymers. We have studied the complexes composed of spherical poly(N-isopropylacrylamide) (PNIPAM) brush and sodium dodecyl sulfate (SDS) micelle in efforts to characterize the flexibility of tethered PNIPAM below the lower critical solution temperature TLCST. An analytical mean-field model is utilized to describe the persistence length Lp in a broad range of ψ, the number of bound micelles per chain. The persistence length of the micelle-constrained PNIPAM is quantitatively correlated with the thermal energy kBT, electrostatic repulsion fC, and effective excluded volume parameter νeff...
October 17, 2016: Journal of Physical Chemistry. B
Guy Herv Eacute, Hedeel Guy Evans, Roshini Fernado, Chandni Patel, Fatme Hachem, David R Evans
Elevated hydrostatic pressure was used to probe conformational changes of Aquifex aeolicus dihydroorotase (DHO) which catalyzes the third step in de novo pyrimidine biosynthesisis. The isolated protein, a 45 kDa monomer, lacks catalytic activity but becomes active upon formation of a dodecameric complex with aspartate transcarbamoylase (ATC). X-ray crystallographic studies of the isolated DHO and of the complex showed that association induces several major conformational changes in the DHO structure. In the isolated DHO, a flexible loop occludes the active site blocking the access of substrates...
October 16, 2016: Journal of Biological Chemistry
Jie Zhang, Alan R Light, Charles L Hoppel, Caitlin Campbell, Carol J Chandler, Dustin J Burnett, Elaine C Souza, Gretchen A Casazza, Ronald W Hughen, Nancy L Keim, John W Newman, Gary R Hunter, Jose R Fernandez, W Timothy Garvey, Mary-Ellen Harper, Oliver Fiehn, Sean H Adams
With insulin-resistance or type 2 diabetes mellitus, mismatches between mitochondrial fatty acid fuel delivery and oxidative phosphorylation/tricarboxylic acid cycle activity may contribute to inordinate accumulation of short- or medium-chain acylcarnitine fatty acid derivatives (markers of incomplete long-chain fatty acid oxidation [FAO]). We reasoned that incomplete FAO in muscle would be ameliorated concurrent with improved insulin sensitivity and fitness following a ∼14 wk training and weight loss intervention in obese, sedentary, insulin-resistant women...
October 12, 2016: Experimental Physiology
Juan Liu, Viktoriia Y Postupalenko, Samuel Loercher, Dalin Wu, Mohamed Chami, Wolfgang Meier, Cornelia G Palivan
Self-organization of nano-components was mainly focused on solid nanoparticles, quantum dots or liposomes to generate complex architectures with specific properties, but intrinsically limited or not developed enough, to mimic sophisticated structures with biological functions in cells. Here, we present a biomimetic strategy to self-organize synthetic nano-compartments (polymersomes) into clusters with controlled properties and topology by exploiting DNA hybridization to interconnect polymersomes. Molecular- and external factors affecting the self-organization served to design clusters mimicking the connection of natural organelles: fine tune of the distance between tethered polymersomes, different topologies, no fusion of clustered polymersomes and no aggregation...
October 11, 2016: Nano Letters
Jiří Hostaš, David Sigwalt, Marina Šekutor, Haresh Ajani, Matúš Dubecký, Jan Řezáč, Peter Y Zavalij, Liping Cao, Christian Wohlschlager, Kata Mlinarić-Majerski, Lyle Isaacs, Robert Glaser, Pavel Hobza
A training set of eleven X-ray structures determined for biomimetic complexes between cucurbit[n]uril (CB[7 or 8]) hosts and adamantane-/diamantane ammonium/aminium guests were studied with DFT-D3 quantum mechanical computational methods to afford ΔGcalcd binding energies. A novel feature of this work is that the fidelity of the BLYP-D3/def2-TZVPP choice of DFT functional was proven by comparison with more accurate methods. For the first time, the CB[n]⋅guest complex binding energy subcomponents [for example, ΔEdispersion , ΔEelectrostatic , ΔGsolvation , binding entropy (-TΔS), and induced fit Edeformation(host) , Edeformation(guest) ] were calculated...
October 10, 2016: Chemistry: a European Journal
Yangyan Li, Wenbo Li, Junliang Zhang
In the past decade, there have been many extraordinary advances in the development of gold-catalyzed enantioselective annulations, such as cycloadditions, cyclizations, cycloisomerizations, and tandem annulations, which are of particular interest owing to their potential for rapid construction of optically active hetero- and carbocyclic molecules. This Review summarizes the methods to construct chiral cyclic compounds by gold-catalyzed enantioselective annulations reported since 2005. The Review is organized according to the general annulation types catalyzed by chiral gold complexes or chiral gold salts, which have four main types (cycloadditions, cyclizations of C-C multiple bonds with tethered nucleophiles, cycloisomerization or cyclization of enynes, and tandem annulations), as well as some other strategies...
October 10, 2016: Chemistry: a European Journal
Sibaprasad Maity, Ekaterina Viazovkina, Alexander Gall, Yuri Lyubchenko
Probing of biomolecular complexes by single-molecule force spectroscopy (SMFS) methods including AFM requires proper and suitable coupling methods for immobilization of biomolecules onto the AFM tip and the surface. The use of flexible tethers for the coupling process has dual advantages. First, they allow the specific immobilization of interacting molecules, and second, their flexibility facilitates the proper orientation of the interacting partners. Recently, we developed an approach termed Flexible Nano Array (FNA) in which interacting partners are located on the same polymeric FNA molecule separated by a flexible segment with a defined length...
2016: Journal of Nature and Science
Bartosz Różycki, Marek Cieplak
Cellulosomes are complex multi-enzyme machineries which efficiently degrade plant cell-wall polysaccharides. The multiple domains of the cellulosome proteins are often tethered together by intrinsically disordered regions. The properties and functions of these disordered linkers are not well understood. In this work, we study endoglucanase Cel8A, which is a relevant enzymatic component of the cellulosomes of Clostridium thermocellum. We use both all-atom and coarse-grained simulations to investigate how the conformations of the catalytic domain of Cel8A are affected by the disordered linker at its C terminus...
September 29, 2016: Molecular BioSystems
Rukmini Mukherjee, Oishee Chakrabarti
Health and homoeostasis are maintained by a dynamic balance between mitochondrial fission and fusion. Mitochondrial fusion machinery is largely unknown in mammals. Only a few reports have illustrated the role of Fzo1 in mitochondrial fusion known in Saccharomyces cerevisiae. We demonstrate that the ubiquitin ligase Mahogunin Ring Finger-1 (MGRN1) interacts with and constitutively ubiquitinates the mammalian homolog, Mitofusin1 (Mfn1) via K63 linkages. In mice models, loss of Mgrn1 function leads to severe developmental defects and adult-onset spongiform neurodegeneration, similar to prion diseases...
October 4, 2016: Biochimica et Biophysica Acta
Gang-Wei Wang, Niall G McCreanor, Megan H Shaw, William G Whittingham, John F Bower
Under carbonylative conditions, neutral Rh(I)-systems modified with weak donor ligands (AsPh3 or 1,4-oxathiane) undergo N-Cbz, N-benzoyl, or N-Ts directed insertion into the proximal C-C bond of aminomethylcyclopropanes to generate rhodacyclopentanone intermediates. These are trapped by N-tethered alkenes to provide complex perhydroisoindoles.
October 6, 2016: Journal of the American Chemical Society
Jonathon D Brzezinski, Roland Felkner, Apexa Modi, Mengdan Liu, Monica J Roth
: The p12 protein of murine leukemia virus (MLV) Gag is associated with the preintegration complex (PIC), and mutants of p12 (PM14) exhibit defects in nuclear entry/retention. Mutants of the phosphorylated serine-61 also have reported defects in the early life cycle. Here we show that a phosphorylated peptide motif derived from human papillomavirus 8 (HPV 8), the E2 hinge region240-255, can functionally replace the main phosphorylated motif of MLV p12 and can rescue the viral titer of a lethal p12-PM14 mutant...
October 5, 2016: Journal of Virology
Jonathon D Brzezinski, Apexa Modi, Mengdan Liu, Monica J Roth
: Murine Leukemia Virus (MLV) p12, encoded within Gag, binds the viral preintegration complex (PIC) to the mitotic chromatin. This acts to anchor the viral PIC in the nucleus as the nuclear envelope reforms post-mitosis. Mutations within the p12 C-terminus (p12 PM13-15) block early stages in viral replication. Within the p12 PM13 region (p12 60PSPMA65), our studies indicated that chromatin tethering is not detected when the wild type p12 protein (M63) was expressed as a GFP fusion, however, constructs bearing p12-I63 were tethered...
October 5, 2016: Journal of Virology
Martha J Snyder, Alyssa C Lau, Elizabeth A Brouhard, Michael B Davis, Jianhao Jiang, Margarita H Sifuentes, Györgyi Csankovszki
Higher order chromosome structure and nuclear architecture can have profound effects on gene regulation. We analyzed how compartmentalizing the genome by tethering heterochromatic regions to the nuclear lamina affects dosage compensation in the nematode C. elegans. In this organism, the dosage compensation complex (DCC) binds both X chromosomes of hermaphrodites to repress transcription two-fold, thus balancing gene expression between XX hermaphrodites and XO males. X chromosome structure is disrupted by mutations in DCC subunits...
September 2016: PLoS Genetics
Doudou Wang, Ryo Nitta, Manatsu Morikawa, Hiroaki Yajima, Shigeyuki Inoue, Hideki Shigematsu, Masahide Kikkawa, Nobutaka Hirokawa
The kinesin-8 motor, KIF19A, accumulates at cilia tips and controls cilium length. Defective KIF19A leads to hydrocephalus and female infertility because of abnormally elongated cilia. Uniquely among kinesins, KIF19A possesses the dual functions of motility along ciliary microtubules and depolymerization of microtubules. To elucidate the molecular mechanisms of these functions we solved the crystal structure of its motor domain and determined its cryo-electron microscopy structure complexed with a microtubule...
September 30, 2016: ELife
Jouliana Sadek, G Sullivan Read
: During lytic herpes simplex virus (HSV) infections, the virion host shutoff (Vhs) (UL41) endoribonuclease degrades many cellular and viral mRNAs. In uninfected cells, spliced mRNAs emerge into the cytoplasm bound by exon junction complexes (EJCs), and are translated several times more efficiently than unspliced mRNAs that have the same sequence, but lack EJCs. Notably, most cellular mRNAs are spliced, whereas most HSV mRNAs are not. To examine the effect of splicing on gene expression during an HSV infection, cells were transfected with plasmids encoding an unspliced renilla luciferase (RLuc) reporter mRNA, or RLuc constructs with introns near the 5' or 3' ends of the gene...
September 28, 2016: Journal of Virology
Muthukumar Kannan, Chinnarasu Sivaprakasam, William A Prinz, Vasanthi Nachiappan
Phosphatidylcholine (PC) and phosphatidylethanolamine (PE) are two of the most abundant phospholipids in cells. Although both lipids can be synthesized in the endoplasmic reticulum (ER), in S. cerevisiae PE can also be produced in mitochondria and endosomes; this PE can be transported back to the ER where it is converted to PC. In this study we found that dithiothreitol (DTT), which induces ER stress, decreases PE export from mitochondria to the ER. This results in decreased levels of total cellular PC and mitochondrial PC...
September 24, 2016: Biochimica et Biophysica Acta
Sanjay B Hari, Robert T Sauer
In eubacteria, the tmRNA system frees ribosomes that stall during protein synthesis and adds an ssrA tag to the incompletely translated polypeptide to target it for degradation. The AAA+ ClpXP protease degrades most ssrA-tagged proteins in the Escherichia coli cytoplasm and was recently shown to degrade an ssrA-tagged protein in the inner membrane. However, we find that tmRNA-mediated tagging of E. coli ProW1-182, a different inner-membrane protein, results in degradation by the membrane-tethered AAA+ FtsH protease...
October 11, 2016: Biochemistry
Raghavendran Ramaswamy, Sarah Goomeshi Nobary, Brett A Eyford, Terry W Pearson, Martin J Boulanger
African trypanosomiasis, caused by parasites of the genus Trypanosoma, is a complex of devastating vector-borne diseases of humans and livestock in sub-Saharan Africa. Central to the pathogenesis of African trypanosomes is their transmission by the arthropod vector, Glossina spp. (tsetse fly). Intriguingly, the efficiency of parasite transmission through the vector is reduced following depletion of Trypanosoma brucei Procyclic-Specific Surface Antigen-2 (TbPSSA-2). To investigate the underlying molecular mechanism of TbPSSA-2, we determined the crystal structures of its ectodomain and that of its homolog T...
September 27, 2016: Protein Science: a Publication of the Protein Society
Fu-Lien Hsieh, Louise Turner, Jani Reddy Bolla, Carol V Robinson, Thomas Lavstsen, Matthew K Higgins
CD36 is a scavenger receptor involved in fatty acid metabolism, innate immunity and angiogenesis. It interacts with lipoprotein particles and facilitates uptake of long chain fatty acids. It is also the most common target of the PfEMP1 proteins of the malaria parasite, Plasmodium falciparum, tethering parasite-infected erythrocytes to endothelial receptors. This prevents their destruction by splenic clearance and allows increased parasitaemia. Here we describe the structure of CD36 in complex with long chain fatty acids and a CD36-binding PfEMP1 protein domain...
2016: Nature Communications
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