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https://www.readbyqxmd.com/read/28231531/concentrations-of-antibodies-against-%C3%AE-amyloid-40-42-monomer-and-oligomers-in-chinese-intravenous-immunoglobulins
#1
Shengliang Ye, Renyong Zeng, Peng Jiang, Mingxia Hou, Fengjuan Liu, Zongkui Wang, Xi Du, Jing Yuan, Yunhua Chen, Haijun Cao, Li Ma, Changqing Li
Intravenous immunoglobulin (IVIg) preparations are being investigated as a potential agent for treatment or prevention of Alzheimer's disease (AD). Antibodies towards soluble β-amyloid (Aβ) contained in IVIg were considered to be the major component contributing to the beneficial effect of the preparations in pilot studies. This study compared the antibody concentrations against Aβ in Octagam(®) IVIg (Octapharma) and 9 IVIg preparations from different Chinese manufacturers by ELISA, using Aβ40 monomer, Aβ40 soluble oligomers, Aβ42 monomer and Aβ42 soluble oligomers as the antigens...
February 17, 2017: Journal of Pharmaceutical and Biomedical Analysis
https://www.readbyqxmd.com/read/28230873/long-stokes-shifts-and-vibronic-couplings-in-perfluorinated-polyanilines
#2
Panagiotis Dallas, Ilija Rašović, Tim Puchtler, Robert A Taylor, Kyriakos Porfyrakis
We report the effect of surfactant addition on the optical properties of perfluorinated polyanilines synthesized through liquid-liquid interfaces. We obtained very long Stokes shifts, 205 nm, for oligomers derived from a hydrofluoroether-water system in the presence of Triton X-100 as a surfactant, and vibronic fine features from a toluene-water system.
February 23, 2017: Chemical Communications: Chem Comm
https://www.readbyqxmd.com/read/28229331/involvement-of-cellular-prion-protein-in-%C3%AE-synuclein-transport-in-neurons
#3
Laura Urrea, Miriam Segura-Feliu, Masami Masuda-Suzukake, Arnau Hervera, Lucas Pedraz, José Manuel García Aznar, Miquel Vila, Josep Samitier, Eduard Torrents, Isidro Ferrer, Rosalina Gavín, Masato Hagesawa, José Antonio Del Río
The cellular prion protein, encoded by the gene Prnp, has been reported to be a receptor of β-amyloid. Their interaction is mandatory for neurotoxic effects of β-amyloid oligomers. In this study, we aimed to explore whether the cellular prion protein participates in the spreading of α-synuclein. Results demonstrate that Prnp expression is not mandatory for α-synuclein spreading. However, although the pathological spreading of α-synuclein can take place in the absence of Prnp, α-synuclein expanded faster in PrP(C)-overexpressing mice...
February 22, 2017: Molecular Neurobiology
https://www.readbyqxmd.com/read/28228551/cysteine-residues-in-a-yeast-viral-a-b-toxin-crucially-control-host-cell-killing-via-ph-triggered-disulfide-rearrangements
#4
Yutaka Suzuki, Sara L Schwartz, Nina C Mueller, Manfred J Schmitt
K28 is a viral A/B protein toxin that intoxicates yeast and fungal cells by endocytosis and retrograde transport to the endoplasmic reticulum (ER). While toxin translocation into the cytosol occurs on the oxidized α/β heterodimer, the precise mechanism of how the toxin crosses the ER membrane is unknown. Here we identified pH-triggered toxin-intrinsic thiol rearrangements that crucially control toxin conformation and host cell killing. In the natural habitat and low pH environment of toxin-secreting killer yeasts, K28 is structurally stable and biologically active as disulfide-bonded heterodimer while it forms inactive disulfide-bonded oligomers at neutral pH that are caused by activation and thiol deprotonation of β-subunit cysteines...
February 22, 2017: Molecular Biology of the Cell
https://www.readbyqxmd.com/read/28228524/structural-insights-into-the-activation-mechanism-of-dynamin-like-ehd-atpases
#5
Arthur Alves Melo, Balachandra G Hegde, Claudio Shah, Elin Larsson, J Mario Isas, Séverine Kunz, Richard Lundmark, Ralf Langen, Oliver Daumke
Eps15 (epidermal growth factor receptor pathway substrate 15)-homology domain containing proteins (EHDs) comprise a family of dynamin-related mechano-chemical ATPases involved in cellular membrane trafficking. Previous studies have revealed the structure of the EHD2 dimer, but the molecular mechanisms of membrane recruitment and assembly have remained obscure. Here, we determined the crystal structure of an amino-terminally truncated EHD4 dimer. Compared with the EHD2 structure, the helical domains are 50° rotated relative to the GTPase domain...
February 22, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28228481/a-helical-bundle-in-the-n-terminal-domain-of-the-blm-helicase-mediates-dimer-and-potentially-hexamer-formation
#6
Jing Shi, Wei-Fei Chen, Bo Zhang, San-Hong Fan, Xia Ai, Na-Nv Liu, Stephane Rety, Xu-Guang Xi
Helicases play a critical role in processes such as replication or recombination by unwinding double-stranded DNA; mutations of these genes can therefore have devastating biological consequences. In human, mutations in genes of three members of the RecQ family helicases (blm, wrn and recq4) give rise to three strikingly distinctive clinical phenotypes: Bloom syndrome, Werner syndrome and Rothmund-Thomson syndrome, respectively. However, the molecular basis for these varying phenotypic outcomes is unclear, in part because a full mechanistic description of helicase activity is lacking...
February 22, 2017: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/28228233/analyzing-complex-mixtures-of-drug-like-molecules-ion-mobility-as-an-adjunct-to-existing-liquid-chromatography-tandem-mass-spectrometry-methods
#7
Jasper Boschmans, Filip Lemière, Frank Sobott
The use of traveling wave ion mobility mass spectrometry (TWIMS) is evaluated in conjunction with, and as a possible alternative to, conventional LC-MS(/MS) methods for the separation and characterization of drug-like compounds and metabolites. As a model system we use an in vitro incubation mixture of the chemotherapeutic agent melphalan, which results in more than ten closely related hydrolysis products and chain-like oligomers. Ion mobility as a filtering tool results in the separation of ions of interest from interfering ions, based on charge state and shape/size...
February 14, 2017: Journal of Chromatography. A
https://www.readbyqxmd.com/read/28225627/1-2-3-triazolium-based-peptoid-oligomers
#8
Hafida Aliouat, Cécile Caumes, Olivier Roy, Mohamed Zouikri, Claude Taillefumier, Sophie Faure
The cis-directing effect of the 1,2,3-triazolium-type side chain was studied on dimeric peptoid models with various patterns: αα, αβ, βα and ββ. Low influences of the sequence and of the solvent were observed, the cis conformation of the amide carrying the triazolium ranging from 83 to 94% in proportion. The synthesis of peptoid homooligomers with four or eight pendant 1,2,3-triazolium side chains is described. α-, β- and α,β-peptoids carrying propargyl groups were subjected to CuAAC reaction using alkyl azides, and the resulting triazoles were quaternized providing well-defined multitriazolium platforms...
February 22, 2017: Journal of Organic Chemistry
https://www.readbyqxmd.com/read/28225612/exciton-absorption-spectra-by-linear-response-methods-application-to-conjugated-polymers
#9
Martin A Mosquera, Nicholas E Jackson, Thomas J Fauvell, Matthew S J Kelley, Lin X Chen, George C Schatz, Mark A Ratner
The theoretical description of the time-evolution of excitons requires, as an initial step, the calculation of their spectra, which has been inaccessible to most users due to the high computational scaling of conventional algorithms, and accuracy issues caused by common density functionals. Previously (J. Chem. Phys., 2016, 144, 204105) we developed a simple method that resolves these issues. Our scheme is based on a two-step calculation in which a linear-response TDDFT calculation is used to generate orbitals perturbed by the excitonic state, and then a second linear-response TDDFT calculation is used to determine the spectrum of excitations relative to the excitonic state...
February 22, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28225193/human-neural-progenitor-transplantation-rescues-behavior-and-reduces-%C3%AE-synuclein-in-a-transgenic-model-of-dementia-with-lewy-bodies
#10
Natalie R S Goldberg, Samuel E Marsh, Joseph Ochaba, Brandon C Shelley, Hayk Davtyan, Leslie M Thompson, Joan S Steffan, Clive N Svendsen, Mathew Blurton-Jones
Synucleinopathies are a group of neurodegenerative disorders sharing the common feature of misfolding and accumulation of the presynaptic protein α-synuclein (α-syn) into insoluble aggregates. Within this diverse group, Dementia with Lewy Bodies (DLB) is characterized by the aberrant accumulation of α-syn in cortical, hippocampal, and brainstem neurons, resulting in multiple cellular stressors that particularly impair dopamine and glutamate neurotransmission and related motor and cognitive function. Recent studies show that murine neural stem cell (NSC) transplantation can improve cognitive or motor function in transgenic models of Alzheimer's and Huntington's disease, and DLB...
February 22, 2017: Stem Cells Translational Medicine
https://www.readbyqxmd.com/read/28223511/a-signal-sequence-suppressor-mutant-that-stabilizes-an-assembled-state-of-the-twin-arginine-translocase
#11
Qi Huang, Felicity Alcock, Holger Kneuper, Justin C Deme, Sarah E Rollauer, Susan M Lea, Ben C Berks, Tracy Palmer
The twin-arginine protein translocation (Tat) system mediates transport of folded proteins across the cytoplasmic membrane of bacteria and the thylakoid membrane of chloroplasts. The Tat system of Escherichia coli is made up of TatA, TatB, and TatC components. TatBC comprise the substrate receptor complex, and active Tat translocases are formed by the substrate-induced association of TatA oligomers with this receptor. Proteins are targeted to TatBC by signal peptides containing an essential pair of arginine residues...
February 21, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28223490/sequential-activation-of-the-three-protomers-in-the-moloney-murine-leukemia-virus-env
#12
Mathilda Sjöberg, Robin Löving, Birgitta Lindqvist, Henrik Garoff
Viral membrane fusion proteins of class I are trimers in which the protomeric unit is a complex of a surface subunit (SU) and a fusion active transmembrane subunit (TM). Here we have studied how the protomeric units of Moloney murine leukemia virus envelope protein (Env) are activated in relation to each other, sequentially or simultaneously. We followed the isomerization of the SU-TM disulfide and subsequent SU release from Env with biochemical methods and found that this early activation step occurred sequentially in the three protomers, generating two asymmetric oligomer intermediates according to the scheme (SU-TM)3 → (SU-TM)2TM → (SU-TM)TM2 → TM3 This was the case both when activation was triggered in vitro by depleting stabilizing Ca(2+) from solubilized Env and when viral Env was receptor triggered on rat XC cells...
February 21, 2017: Proceedings of the National Academy of Sciences of the United States of America
https://www.readbyqxmd.com/read/28223356/molecular-insights-into-hydrogen-peroxide-sensing-mechanism-of-the-metalloregulator-mntr-in-controlling-bacterial-resistance-to-oxidative-stresses
#13
Zhaoyuan Chen, Xinhui Wang, Fan Yang, Qingqing Hu, Huichun Tong, Xiuzhu Dong
Manganese contributes to anti-oxidative stress particularly in catalase-devoid bacteria, and DtxR family metalloregulators, through sensing cellular Mn(2+) content, regulate its homeostasis. Here, we show that metalloregulator MntR (So-MntR) functions dually as Mn(2+) and H2O2 sensors in mediating H2O2 resistance by an oral streptococcus. H2O2 disrupted So-MntR's binding to Mn(2+) transporter mntABC promoter, and induced disulfide-linked dimerization of the protein. Mass spectrometry identified Cys11-Cys156 and Cys11-Cys11 disulfide-linked peptides in H2O2 treated So-MntR...
February 21, 2017: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/28221361/dynamic-control-of-chirality-and-self-assembly-of-double-stranded-helicates-with-light
#14
Depeng Zhao, Thomas van Leeuwen, Jinling Cheng, Ben L Feringa
Helicity switching in biological and artificial systems is a fundamental process that allows for the dynamic control of structures and their functions. In contrast to chemical approaches to responsive behaviour in helicates, the use of light as an external stimulus offers unique opportunities to invert the chirality of helical structures in a non-invasive manner with high spatiotemporal precision. Here, we report that unidirectional rotary motors with connecting oligobipyridyl ligands, which can dynamically change their chirality upon irradiation, assemble into metal helicates that are responsive to light...
March 2017: Nature Chemistry
https://www.readbyqxmd.com/read/28221031/%C3%AF-conjugated-discrete-oligomers-containing-planar-and-nonplanar-aromatic-motifs
#15
Ji Li, Anamaria Terec, Yue Wang, Hrishikesh Joshi, Yunpeng Lu, Handong Sun, Mihaiela C Stuparu
A new family of π-conjugated oligomers featuring a nonplanar polycyclic aromatic hydrocarbon, corannulene, and a planar aromatic unit, thiophene, is synthesized through an iterative metal-catalyzed coupling protocol. The two structural motifs are connected through an acetylene linkage. In the shorter oligomers, a thiophene unit is attached to one or two corannulenes. In the higher analogues, two, three, and four thiophene units are placed in an alternating fashion with three, four, and five corannulene units, respectively...
February 21, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28220001/refractive-index-sensing-with-fano-resonances-in-silicon-oligomers
#16
Katie E Chong, Henry W Orton, Isabelle Staude, Manuel Decker, Andrey E Miroshnichenko, Igal Brener, Yuri S Kivshar, Dragomir N Neshev
We demonstrate experimentally refractive index sensing with localized Fano resonances in silicon oligomers, consisting of six disks surrounding a central one of slightly different diameter. Owing to the low absorption and narrow Fano-resonant spectral features appearing as a result of the interference of the modes of the outer and the central disks, we demonstrate refractive index sensitivity of more than 150 nm RIU(-1) with a figure of merit of 3.8.This article is part of the themed issue 'New horizons for nanophotonics'...
March 28, 2017: Philosophical Transactions. Series A, Mathematical, Physical, and Engineering Sciences
https://www.readbyqxmd.com/read/28219316/from-disorder-to-mis-order-structural-aspects-of-pathogenic-oligomerization-in-conformational-diseases
#17
Chin Pang Benny Yiu, Yu Wai Chen
Proteins implicated in neurological conformational diseases contain substantial amounts of "intrinsic disorder". These native monomeric functional states may transit into some oligomeric states that have high β-sheet contents and seed the formation of insoluble amyloid fibrils. The prevailing view is that these "toxic" oligomers should be targeted for drug development. Here, an overview of the diseases was presented, within the general framework of the oligomerization of intrinsically disordered proteins. These systems pose some specific challenges to structural studies: the toxic oligomers are transient, low in concentration, and often need to be studied in a heterogeneous environment...
February 20, 2017: Protein and Peptide Letters
https://www.readbyqxmd.com/read/28219245/real-time-analysis-of-binding-events-between-different-a%C3%AE-1-42-species-and-human-lilrb2-by-dual-polarization-interferometry
#18
Tao Hu, Shuang Wang, Chuanxia Chen, Jian Sun, Xiurong Yang
Abnormal accumulation of 42-residue amyloid-β (Aβ1-42) within the brain triggers the pathogenesis of Alzheimer's disease (AD). In this paper, we use a dual polarization interferometry (DPI) tool to evaluate the binding events of various Aβ1-42 species such as monomeric Aβ1-42, low molecular weight Aβ1-42 oligomer (LMW Aβ1-42), and high molecular weight Aβ1-42 oligomer (HMW Aβ1-42) with extracellular D1D2 domain of lilrb2 (ED1D2L) receptor that has been proved to be associated with AD. Based on the real-time binding information provided by DPI, the association rate (ka) of ED1D2L receptor with monomeric Aβ1-42, LMW Aβ1-42, and HMW Aβ1-42 is individually determined to be 2...
February 21, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28219012/the-tyrosinase-catalyzed-oxidation-of-the-leukoderma-inducing-agent-raspberry-ketone-produces-e-4-3-oxo-1-butenyl-1-2-benzoquinone-implications-for-melanocyte-toxicity
#19
Shosuke Ito, Maki Hinoshita, Erina Suzuki, Makoto Ojika, Kazumasa Wakamatsu
The exposure of human skin to 4-(4-hydroxyphenyl)-2-butanone (raspberry ketone, RK) is known to cause chemical/occupational leukoderma. RK has a structure closely related to 4-(4-hydroxyphenyl)-2-butanol (rhododendrol), a skin whitening agent that was found to cause leukoderma in the skin of consumers in 2013. Rhododendrol is a good substrate for tyrosinase and causes a tyrosinase-dependent cytotoxicity to melanocytes, cells that are responsible for skin pigmentation. Therefore, it is expected that RK exerts its cytotoxicity to melanocytes through the tyrosinase-catalyzed oxidation to cytotoxic o-quinones...
February 20, 2017: Chemical Research in Toxicology
https://www.readbyqxmd.com/read/28218833/atomic-force-microscopy-thermally-assisted-microsampling-with-atmospheric-pressure-temperature-ramped-thermal-desorption-ionization-mass-spectrometry-analysis
#20
William D Hoffmann, Vilmos Kertesz, Bernadeta R Srijanto, Gary J Van Berkel
The use of atomic force microscopy controlled nanothermal analysis probes for reproducible spatially resolved thermally assisted sampling of micrometer-sized areas (ca. 11 × 17 μm wide × 2.4 μm deep) from relatively low number-average molecular weight (Mn < 3000) polydisperse thin films of poly(2-vinylpyridine) (P2VP) is presented. Following sampling, the nanothermal analysis probes were moved up from the surface and the probe temperature ramped to liberate the sampled materials into the gas phase for atmospheric pressure chemical ionization and mass spectrometric analysis...
February 20, 2017: Analytical Chemistry
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