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Tethering complex

Paresh A Parmar, Jean-Philippe St-Pierre, Lesley W Chow, Christopher D Spicer, Violet Stoichevska, Yong Y Peng, Jerome A Werkmeister, John A M Ramshaw, Molly M Stevens
: Recapitulation of the articular cartilage microenvironment for regenerative medicine applications faces significant challenges due to the complex and dynamic biochemical and biomechanical nature of native tissue. Towards the goal of biomaterial designs that enable the temporal presentation of bioactive sequences, recombinant bacterial collagens such as Streptococcal collagen-like 2 (Scl2) proteins can be employed to incorporate multiple specific bioactive and biodegradable peptide motifs into a single construct...
January 10, 2017: Acta Biomaterialia
Batoul Farran
The traditional view on GPCRs held that they function as single monomeric units composed of identical subunits. This notion was overturned by the discovery that GPCRs can form homo- and hetero-oligomers, some of which are obligatory, and can further assemble into receptor mosaics consisting of three or more protomers. Oligomerisation exerts significant impacts on receptor function and physiology, offering a platform for the diversification of receptor signalling, pharmacology, regulation, crosstalk, internalization and trafficking...
January 10, 2017: Pharmacological Research: the Official Journal of the Italian Pharmacological Society
Hiwa Saeed, Ibrahim Saeed, Niklaas Buurma, Jim Antony Thomas
With the long-term aim of enhancing the binding properties of dinuclear RuII-based DNA light-switch complexes, a series of eight structurally related mono- and dinuclear systems are reported in which the linker of the bridging ligand has been modulated. These tethered systems have been designed to explore issues of steric demand at the binding site and the thermodynamic cost of entropy loss upon binding. An analysis of detailed spectroscopic and isothermal titration calorimetry (ITC) studies on the new complexes reveal that one of the linkers produces a dinuclear systems that binds to duplex DNA with an affinity (Kb > 107 M-1) that is higher than its corresponding monometallic complex and is the highest affinity for a non-threading bis-intercalating metal complex...
January 10, 2017: Chemistry: a European Journal
Thuy Pham, Fanwei Kong, Caitlin Martin, Qian Wang, Charles Primiano, Raymond McKay, John Elefteriades, Wei Sun
Functional mitral regurgitation (FMR) is a significant complication of left ventricular dysfunction and strongly associated with a poor prognosis. In this study, we developed a patient-specific finite element (FE) model of the mitral apparatus in a FMR patient which included: both leaflets with thickness, annulus, chordae tendineae, and chordae insertions on the leaflets and origins on the papillary muscles. The FE model incorporated human age- and gender-matched anisotropic hyperelastic material properties, and MV closure at systole was simulated...
January 9, 2017: Cardiovascular Engineering and Technology
Akihito Shimazu, Masashi Kawagoshi, Shoichi Takeda, Haruaki Kurasaki, Asako Kato, Nahoko Morii, Norio Sakai, Takeo Konakahara
The binding modes and binding constants for the complexes of forty types of pyridocarbazole derivatives 1-40 with double stranded DNAs (dsDNAs) were reported. The binding modes were determined by a combination of a deflection spectroscopy and orientation of the corresponding molecule in the DNA-based film with chain alignment. All of the compounds exhibited the intercalation-binding mode. Its binding constants Ka for the complexes, determined by quartz crystal microbalance (QCM), varied from 1.7×10(5) to 4...
December 27, 2016: Bioorganic & Medicinal Chemistry
Naonobu Fujita, Wilson Huang, Tzu-Han Lin, Jean-Francois Groulx, Steve Jean, Yoshihiko Kuchitsu, Ikuko Koyama-Honda, Noboru Mizushima, Mitsunori Fukuda, Amy A Kiger
Transverse (T)-tubules make-up a specialized network of tubulated muscle cell membranes involved in excitation-contraction coupling for power of contraction. Little is known about how T-tubules maintain highly organized structures and contacts throughout the contractile system despite the ongoing muscle remodeling that occurs with muscle atrophy, damage and aging. We uncovered an essential role for autophagy in T-tubule remodeling with genetic screens of a developmentally regulated remodeling program in Drosophila abdominal muscles...
January 7, 2017: ELife
S Ucuncuoglu, D A Schneider, E R Weeks, D Dunlap, L Finzi
DNA is the carrier of genetic information and, as such, is at the center of most essential cellular processes. To regulate its physiological function, specific proteins and motor enzymes constantly change conformational states with well-controlled dynamics. Twenty-five years ago, Schafer, Gelles, Sheetz, and Landick employed the tethered particle motion (TPM) technique for the first time to study transcription by RNA polymerase at the single-molecule level. TPM has since then remained one of the simplest, most affordable, and yet incisive single-molecule techniques available...
2017: Methods in Enzymology
Jasvinder S Ahuja, Rima Sandhu, Rana Mainpal, Crystal Lawson, Hanna Henley, Patricia A Hunt, Judith L Yanowitz, G Valentin Börner
During meiosis, paired homologous chromosomes (homologs) become linked via the synaptonemal complex (SC) and crossovers. Crossovers mediate homolog segregation and arise from self-inflicted double-strand breaks (DSBs). Here, we identified a role for the proteasome, the multi-subunit protease that degrades proteins in the nucleus and cytoplasm, in homolog juxtaposition and crossing over. Without proteasome function, homologs failed to pair and instead remained associated with non-homologous chromosomes. While dispensable for non-crossover formation, a functional proteasome was required for a coordinated transition that entails SC assembly between longitudinally organized chromosome axes and stable strand exchange of crossover-designated DSBs...
January 5, 2017: Science
Mélodie Duval, Alessandra Marenna, Clément Chevalier, Stefano Marzi
RNA-protein interactions are at the bases of many biological processes, forming either tight and stable functional ribonucleoprotein (RNP) complexes (i.e. the ribosome) or transitory ones, such as the complexes involving RNA chaperone proteins. To localize the sites where a protein interacts on an RNA molecule, a common simple and inexpensive biochemical method is the footprinting technique. The protein leaves its footprint on the RNA acting as a shield to protect the regions of interaction from chemical modification or cleavages obtained with chemical or enzymatic nucleases...
December 24, 2016: Methods: a Companion to Methods in Enzymology
Inbal Samuk, Marc Levitt, Elena Dlugy, Dragan Kravarusic, David Ben-Meir, Gustavo Rajz, Osnat Konen, Enrique Freud
Caudal duplication syndrome is a rare entity that describes the association between congenital anomalies involving caudal structures and may have a wide spectrum of clinical manifestations. A full-term male presented with combination of anomalies including anorectal malformation, duplication of the colon and lower urinary tract, split of the lower spine, and lipomyelomeningocele with tethering of the cord. We report this exceptional case of caudal duplication syndrome with special emphasis on surgical strategy and approach combining all disciplines involved...
December 2016: European Journal of Pediatric Surgery Reports
Alejandro Méndez-Ardoy, Tom Steentjes, Bernard A Boukamp, Pascal Jonkheijm, Tibor Kudernac, Jurriaan Huskens
The effect of the distance between a β-cyclodextrin (βCD) host core and a conductive substrate on the electron transfer rate of complexed guests as well as of free-diffusing electrochemically active probes has been studied. First we have evaluated a set of short tethered βCD adsorbates bearing different anchoring groups in order to get a reliable platform for the study of short-distance electron transfer. An electrochemically active trivalent guest was immobilized on these host monolayers in a selective and reversible manner, providing information about the packing density...
December 25, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
Li-Ka Liu, Vineet Choudhary, Alexandre Toulmay, William A Prinz
Ceramides are key intermediates in sphingolipid biosynthesis and potent signaling molecules. However, excess ceramide is toxic, causing growth arrest and apoptosis. In this study, we identify a novel mechanism by which cells prevent the toxic accumulation of ceramides; they facilitate nonvesicular ceramide transfer from the endoplasmic reticulum (ER) to the Golgi complex, where ceramides are converted to complex sphingolipids. We find that the yeast protein Nvj2p promotes the nonvesicular transfer of ceramides from the ER to the Golgi complex...
January 2, 2017: Journal of Cell Biology
Chunman Li, Xiaomin Luo, Shan Zhao, Gavin Ky Siu, Yongheng Liang, Hsiao Chang Chan, Ayano Satoh, Sidney Sb Yu
The transport protein particle (TRAPP) was initially identified as a vesicle tethering factor in yeast and as a guanine nucleotide exchange factor (GEF) for Ypt1/Rab1. In mammals, structures and functions of various TRAPP complexes are beginning to be understood. We found that mammalian TRAPPII was a GEF for both Rab18 and Rab1. Inactivation of TRAPPII-specific subunits by various methods including siRNA depletion and CRISPR-Cas9-mediated deletion reduced lipolysis and resulted in aberrantly large lipid droplets...
December 21, 2016: EMBO Journal
Anup K Pramanik, Siddikuzzaman, Duraippandi Palanimuthu, Kumaravel Somasundaram, Ashoka G Samuelson
The synthesis and anticancer activity of a copper(II) diacetyl-bis(N4-methylthiosemicarbazone) complex and its nanoconjugates are reported. The copper(II) complex is connected to a carboxylic acid group through a cleavable disulfide link to enable smart delivery. The copper complex is tethered to highly water-soluble 20 nm gold nanoparticles (AuNPs), stabilized by amine terminated lipoic acid-polyethylene glycol (PEG). The gold nanoparticle carrier was further decorated with biotin to achieve targeted action...
December 21, 2016: Bioconjugate Chemistry
Shunsuke Matsumoto, Yuya Taguchi, Atsushi Shimada, Mayumi Igura, Daisuke Kohda
Oligosaccharyltransferase (OST) transfers an oligosaccharide chain to the Asn residue in the Asn-X-Ser/Thr sequon in proteins, where X is not proline. A sequon was tethered to an archaeal OST enzyme via a disulfide bond. The positions of the cysteine residues in the OST protein and the sequon-containing acceptor peptide were selected by reference to the eubacterial OST structure in a non-covalent complex with an acceptor peptide. We determined the crystal structure of the cross-linked OST-sequon complex. The Ser/Thr-binding pocket recognizes the Thr residue in the sequon, and the catalytic structure referred to as 'carboxylate dyad' interacted with the Asn residue...
December 20, 2016: Biochemistry
Chenglin Yi, Shaoyi Zhang, Kyle Thomas Webb, Zhihong Nie
Current interest in functional assemblies of inorganic nanoparticles (NPs) stems from their collective properties and diverse applications ranging from nanomedicines to optically active metamaterials. Coating the surface of NPs with polymers allows for tailoring of the interactions between NPs to assemble them into hybrid nanocomposites with targeted architectures. This class of building blocks is termed "hairy" inorganic NPs (HINPs). Regiospecific attachment of polymers has been used to achieve directional interactions for HINP assembly...
December 20, 2016: Accounts of Chemical Research
Michael M H Graf, Sandra Weber, Daniel Kracher, Roman Kittl, Christoph Sygmund, Roland Ludwig, Clemens Peterbauer, Dietmar Haltrich
Multigenicity is commonly found in fungal enzyme systems, with the purpose of functional compensation upon deficiency of one of its members or leading to enzyme isoforms with new functionalities through gene diversification. Three genes of the flavin-dependent glucose-methanol-choline (GMC) oxidoreductase pyranose dehydrogenase (AmPDH) were previously identified in the litter-degrading fungus Agaricus (Leucoagaricus) meleagris, of which only AmPDH1 was successfully expressed and characterized. The aim of this work was to study the biophysical and biochemical properties of AmPDH2 and AmPDH3 and compare them with those of AmPDH1...
December 19, 2016: Applied Microbiology and Biotechnology
Zaizai Tong, Runke Zhang, Pianpian Ma, Haian Xu, Hua Chen, Yanming Li, Weijiang Yu, Wangqian Zhuo, Guohua Jiang
A series of crystalline/ionic complexed block copolymers (BCPs) with various compositions have been prepared by sequential reactions. The BCPs with different hydrophilic fractions can self-assemble into various morphologies, such as spindlelike, rodlike, and spherical micelles with different crystallinity of the core. Bis(2-ethylhexyl) sulfosuccinate sodium salt (AOT) is added as a surfactant to induce the morphological transition of BCPs in aqueous media. The introduced AOT can be tightly bound to the cationic units, and a water-insoluble unit in the corona forms, leading to a reduced tethering density...
December 19, 2016: Langmuir: the ACS Journal of Surfaces and Colloids
Hsiu-Fang Fan, Tao-Shih Hsieh, Chien-Hui Ma, Makkuni Jayaram
Serine and tyrosine site-specific recombinases (SRs and YRs, respectively) provide templates for understanding the chemical mechanisms and conformational dynamics of strand cleavage/exchange between DNA partners. Current evidence suggests a rather intriguing mechanism for serine recombination, in which one half of the cleaved synaptic complex undergoes a 180° rotation relative to the other. The 'small' and 'large' SRs contain a compact amino-terminal catalytic domain, but differ conspicuously in their carboxyl-terminal domains...
December 15, 2016: Nucleic Acids Research
Humphrey L C Feltham, Christophe Dumas, Matteo Mannini, Edwige Otero, Philippe Sainctavit, Roberta Sessoli, Carla J Meledandri, Sally Brooker
In a proof-of-principle study, a soluble macrocyclic single-molecule magnet (SMM) containing a Cu(II)3 Tb(III) magnetic core was covalently grafted onto small gold nanoparticles pre-functionalised with carboxylate-terminated tethers. A modified microemulsion method allowed production of the small and monodisperse nanoparticles (approximately 3.5 nm in diameter) for the chemisorption of a large amount of intact macrocyclic complexes in the hybrid system.
November 6, 2016: Chemistry: a European Journal
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