keyword
MENU ▼
Read by QxMD icon Read
search

Covalent labeling

keyword
https://www.readbyqxmd.com/read/29148785/rapid-quantitative-measurements-of-paramagnetic-relaxation-enhancements-in-cu-ii-tagged-proteins-by-proton-detected-solid-state-nmr-spectroscopy
#1
Dwaipayan Mukhopadhyay, Philippe S Nadaud, Matthew D Shannon, Christopher P Jaroniec
We demonstrate rapid quantitative measurements of site-resolved paramagnetic relaxation enhancements (PREs), which are a source of valuable structural restraints corresponding to electron-nucleus distances in the ~10-20 Å regime, in solid-state nuclear magnetic resonance (NMR) spectra of proteins containing covalent Cu(2+)-binding tags. Specifically, using protein GB1 K28C-EDTA-Cu(2+) mutant as a model, we show the determination of backbone amide (15)N longitudinal and (1)H transverse PREs within a few hours of experiment time based on proton-detected 2D or 3D correlation spectra recorded with magic-angle spinning frequencies ≥ ~60 kHz for samples containing ~10-50 nanomoles of (2)H,(13)C,(15)N-labeled protein back-exchanged in H2O...
November 17, 2017: Journal of Physical Chemistry Letters
https://www.readbyqxmd.com/read/29148719/effect-of-antigen-retrieval-methods-on-non-specific-binding-of-anti-body-metal-nanoparticle-conjugates-on-ffpe-tissue
#2
Yuying Zhang, Xinping Wang, Sven Perner, Ágnes Bánkfalvi, Sebastian Schlücker
Immunohistochemical analysis of FFPE tissues provides important diagnostic and prognostic information in pathology. Metal nanoparticles (NPs) and in particular surface-enhanced Raman scattering (SERS) nanotags as a new class of labelling reagents are promising to be used for multiplexed protein profiling on tissue sections. However, non-specific binding of NPs onto the tissue specimens greatly hampers their clinical applications. In this study, we found that the antigen retrieval method strongly influences the extent of non-specific binding of the antibody-SERS NP conjugates to the tissue...
November 17, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/29141403/lipogels-for-encapsulation-of-hydrophilic-proteins-and-hydrophobic-small-molecules
#3
Celia C Homyak, Ann Fernandez, Mollie A Touve, Bo Zhao, Francesca Anson, Jeanne A Hardy, Richard W Vachet, Nathan C Gianneschi, Jennifer L Ross, S Thayumanavan
Lipid-polymer hybrid materials have the potential to exhibit enhanced stability and loading capabilities in comparison to parent liposome or polymer materials. However, complexities lie in formulating and characterizing such complex nanomaterials. Here we describe a lipid-coated polymer gel (lipogel) formulated using a one-pot methodology, where self-assembling liposomes template a UV-curable polymer gel core. Using fluorescently-labeled lipids, protein, and hydrophobic molecules, we have characterized their formation, purification, stability, and encapsulation efficiency via common instrumentation methods such as dynamic light scattering (DLS), matrix-assisted laser desorption ionization-mass spectrometry (MALDI-MS), UV-Visible spectroscopy, fluorescence spectroscopy, and single particle total internal reflection fluorescence (TIRF) microscopy...
November 15, 2017: Biomacromolecules
https://www.readbyqxmd.com/read/29137172/fluorescent-magnetopolymersomes-a-theranostic-platform-to-track-intracellular-delivery
#4
Oliver Bixner, Noga Gal, Christoph Zaba, Andrea Scheberl, Erik Reimhult
We present a potential theranostic delivery platform based on the amphiphilic diblock copolymer polybutadiene-block-poly (ethylene oxide) combining covalent fluorescent labeling and membrane incorporation of superparamagnetic iron oxide nanoparticles for multimodal imaging. A simple self-assembly and labeling approach to create the fluorescent and magnetic vesicles is described. Cell uptake of the densely PEGylated polymer vesicles could be altered by surface modifications that vary surface charge and accessibility of the membrane active species...
November 13, 2017: Materials
https://www.readbyqxmd.com/read/29136915/a-quantum-dot-based-lateral-flow-immunoassay-for-the-sensitive-detection-of-human-heart-fatty-acid-binding-protein-hfabp-in-human-serum
#5
Mihaela Savin, Carmen-Marinela Mihailescu, Iulia Matei, Dana Stan, Carmen Aura Moldovan, Marian Ion, Ion Baciu
We describe the preparation and validation of a novel lateral flow immunoassay test for the detection of human heart fatty acid binding protein (hFABP). Water-soluble CdTe quantum dots (QDs) were selected as the fluorescent label and were linked covalently to anti-hFABP antibodies. Upon conjugation, the secondary structure of the anti-hFABP was preserved and the fluorescence quantum yield of the CdTe QDs increased. The labelled antibodies were transferred to the immunoassay test strip and the antigen-antibody reaction was successfully performed...
February 1, 2018: Talanta
https://www.readbyqxmd.com/read/29136199/site-specific-dual-color-labeling-of-long-rnas-for-single-molecule-spectroscopy
#6
Meng Zhao, Fabio D Steffen, Richard Börner, Michelle F Schaffer, Roland K O Sigel, Eva Freisinger
Labeling of long RNA molecules in a site-specific yet generally applicable manner is integral to many spectroscopic applications. Here we present a novel covalent labeling approach that is site-specific and scalable to long intricately folded RNAs. In this approach, a custom-designed DNA strand that hybridizes to the RNA guides a reactive group to target a preselected adenine residue. The functionalized nucleotide along with the concomitantly oxidized 3'-terminus can subsequently be conjugated to two different fluorophores via bio-orthogonal chemistry...
November 9, 2017: Nucleic Acids Research
https://www.readbyqxmd.com/read/29135000/bioconjugated-fluorescent-organic-nanoparticles-targeting-egfr-overexpressing-cancer-cells
#7
Adrien Faucon, Houda Benhelli-Mokrani, Fabrice Fleury, Stéphanie Dutertre, Marc Tramier, Joanna Boucard, Lénaïc Lartigue, Steven Nedellec, Philippe Hulin, Eléna Ishow
The field of optical bioimaging has considerably flourished with the advent of sophisticated microscopy techniques and ultra-bright fluorescent tools. Fluorescent organic nanoparticles (FONs) have thus recently appeared as very attractive labels for their high payload, absence of cytotoxicity and eventual biodegradation. Nevertheless, their bioconjugation to target specific receptors with high imaging contrast is scarcely performed. Moreover, assessing the reality of bioconjugation represents high challenges given the sub-nanomolar concentrations resulting from the commonly adopted nanoprecipitation fabrication process...
November 14, 2017: Nanoscale
https://www.readbyqxmd.com/read/29127943/quantum-dot-cramoll-lectin-as-novel-conjugates-to-glycobiology
#8
Cássia R A Cunha, Camila G Andrade, Maria I A Pereira, Paulo E Cabral Filho, Luiz B Carvalho, Luana C B B Coelho, Beate S Santos, Adriana Fontes, Maria T S Correia
The optical properties of quantum dots (QDs) make them useful tools for biology, especially when combined with biomolecules such as lectins. QDs conjugated to lectins can be used as nanoprobes for carbohydrate expression analysis, which can provide valuable information about glycosylation changes related to cancer and pathogenicity of microorganisms, for example. In this study, we evaluated the best strategy to conjugate Cramoll lectin to QDs and used the fluorescent labeling of Candida albicans cells as a proof-of-concept...
October 25, 2017: Journal of Photochemistry and Photobiology. B, Biology
https://www.readbyqxmd.com/read/29119789/graphene-oxide-thin-film-with-dual-function-integrated-into-a-nano-sandwich-device-for-in-vivo-monitoring-of-interleukin-6
#9
Meng Qi, Jiawei Huang, Hui Wei, Chaomin Cao, Shilun Feng, Qing Guo, Ewa M Goldys, Rui Li, Guozhen Liu
Graphene oxide (GO), with its exceptional physical and chemical properties and biocompatibility, holds a tremendous potential for sensing applications. In this study, GO, acting both as the electron transfer bridge and the signal reporter, was attached on the interface to develop a label-free electrochemical nanosandwich device for detection of interleukin 6 (IL-6). First, a single layer of GO was covalently modified on gold electrodes followed by attachment of anti-IL-6 capture antibody to form the sensing interface...
November 9, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/29109777/improved-tumor-targeting-and-longer-retention-time-of-nir-fluorescent-probes-using-bioorthogonal-chemistry
#10
Xianghan Zhang, Bo Wang, Na Zhao, Zuhong Tian, Yunpeng Dai, Yongzhan Nie, Jie Tian, Zhongliang Wang, Xiaoyuan Chen
The traditional labeling method for targeted NIR fluorescence probes requires directly covalent-bonded conjugation of targeting domains and fluorophores in vitro. Although this strategy works well, it is not sufficient for detecting or treating cancers in vivo, due to steric hindrance effects that relatively large fluorophore molecules exert on the configurations and physiological functions of specific targeting domains. The copper-free, "click-chemistry"-assisted assembly of small molecules in living systems may enhance tumor accumulation of fluorescence probes by improving the binding affinities of the targeting factors...
2017: Theranostics
https://www.readbyqxmd.com/read/29108109/inserting-porphyrin-quantum-dots-in-bottom-up-synthesized-graphene-nanoribbons
#11
Wade Perkins, Felix Raoul Fischer
Diels-Alder copolymerization of tetrapheneylcycopenta-dienone, a precursor for cove graphene nanoribbons (cGNRs), with bifunctional porphyrins yields defined nanostructures comprised of a single cGNR-porphyrin-cGNR heterojunction within each ribbon. 13C-NMR labeling and high-resolution mass spectrometry of solubilized polymer intermediates indicates that every porphyrin is covalently linked to two extended segments of cGNRs. UV-Vis absorption and fluorescence emission spectroscopy reveal a strong electronic correlation between the porphyrin and the adjacent cGNR segments that can be attenuated through reversible metalation of the porphyrin core...
November 6, 2017: Chemistry: a European Journal
https://www.readbyqxmd.com/read/29097031/on-site-reaction-for-ppar%C3%AE-modification-using-a-specific-bifunctional-ligand
#12
Hiroyuki Kojima, Toshimasa Itoh, Keiko Yamamoto
Site-specific labeling is an important methodology to elucidate the biological function of a target protein. Here, we report a strategy for site-specific chemical labeling, termed the "on-site reaction". We designed and readily synthesized a bifunctional ligand possessing two reaction sites, an enone and an azide moiety. This strategy involves an on-site conjugate addition reaction with protein followed by a Hüisgen cycloaddition reaction. We demonstrate this strategy by using fluorescein as a probe and peroxisome proliferator activated receptor γ (PPARγ) as a target protein...
October 23, 2017: Bioorganic & Medicinal Chemistry
https://www.readbyqxmd.com/read/29083874/mapping-the-small-molecule-interactome-by-mass-spectrometry
#13
Hope Airlie Flaxman, Christina M Woo
Mapping small molecule interactions throughout the proteome provides the critical structural basis for functional analysis of their impact on biochemistry. However, translation of mass spectrometry-based proteomics methods to directly profile the interaction between a small molecule and the whole proteome is challenging due to the substoichiometric nature of many interactions, the diversity of covalent and noncovalent interactions involved, and the subsequent computational complexity associated with spectral assignment...
October 30, 2017: Biochemistry
https://www.readbyqxmd.com/read/29081948/fluorescent-turn-on-probes-for-wash-free-mrna-imaging-via-covalent-site-specific-enzymatic-labeling
#14
Cun Yu Zhou, Seth C Alexander, Neal K Devaraj
Investigating the many roles RNA plays in cellular regulation and function has increased demand for tools to explore RNA tracking and localization within cells. Our recently reported RNA-TAG (transglycosylation at guanine) approach uses an RNA-modifying enzyme, tRNA-guanine transglycosylase (TGT), to accomplish covalent labeling of an RNA of interest with fluorescent tracking agents in a highly selective and efficient manner. Unfortunately, labeling by this method currently suffers from a high nonspecific fluorescent background and is currently unsuitable for imaging RNA within complex cellular environments...
October 1, 2017: Chemical Science
https://www.readbyqxmd.com/read/29068008/the-influence-of-covalent-immobilization-conditions-on-antibody-accessibility-on-nanoparticles
#15
Bedabrata Saha, Pål Songe, Toon H Evers, Menno W J Prins
The accessibility of particle-coupled antibodies is important for many analytical applications, but comprehensive data on parameters controlling the accessibility are scarce. Here we report on the site-specific accessibility of monoclonal antibodies, immobilized on magnetic nanoparticles (500 nm) by the widely used covalent EDC coupling method, with the variation of four key coupling parameters (surface activation and immobilization pH, crosslinker and antibody concentration ratios). By developing quantitative radio-labelled assays, the number of immobilized antibodies, the Fab domain accessibility (in a sandwich immunoassay), and the Fc domain accessibility (in a Protein G assay) were determined...
October 25, 2017: Analyst
https://www.readbyqxmd.com/read/29045385/usp7-small-molecule-inhibitors-interfere-with-ubiquitin-binding
#16
Lorna Kategaya, Paola Di Lello, Lionel Rougé, Richard Pastor, Kevin R Clark, Jason Drummond, Tracy Kleinheinz, Eva Lin, John-Paul Upton, Sumit Prakash, Johanna Heideker, Mark McCleland, Maria Stella Ritorto, Dario R Alessi, Matthias Trost, Travis W Bainbridge, Michael C M Kwok, Taylur P Ma, Zachary Stiffler, Bradley Brasher, Yinyan Tang, Priyadarshini Jaishankar, Brian R Hearn, Adam R Renslo, Michelle R Arkin, Frederick Cohen, Kebing Yu, Frank Peale, Florian Gnad, Matthew T Chang, Christiaan Klijn, Elizabeth Blackwood, Scott E Martin, William F Forrest, James A Ernst, Chudi Ndubaku, Xiaojing Wang, Maureen H Beresini, Vickie Tsui, Carsten Schwerdtfeger, Robert A Blake, Jeremy Murray, Till Maurer, Ingrid E Wertz
The ubiquitin system regulates essential cellular processes in eukaryotes. Ubiquitin is ligated to substrate proteins as monomers or chains and the topology of ubiquitin modifications regulates substrate interactions with specific proteins. Thus ubiquitination directs a variety of substrate fates including proteasomal degradation. Deubiquitinase enzymes cleave ubiquitin from substrates and are implicated in disease; for example, ubiquitin-specific protease-7 (USP7) regulates stability of the p53 tumour suppressor and other proteins critical for tumour cell survival...
October 26, 2017: Nature
https://www.readbyqxmd.com/read/29043360/synthesis-photophysical-and-biological-properties-of-a-new-oxazolone-fluorescent-probe-for-bioimaging-an-experimental-and-theoretical-study
#17
Przemysław Krawczyk, Beata Jędrzejewska, Piotr Cysewski, Tomasz Janek
In this study, a new oxazolone derivative 4-{N,N-bis[2-phenyl-4-benzylidene-1,3-oxazol-5(4H)-one]amino}benzaldehyde (PB3) was synthesized and investigated as a fluorescent dye. The spectroscopic properties in different solvents were thoroughly studied. The experimental data were supported by quantum-chemical calculations using density functional theory. Measurements and theoretical calculations showed that the PB3 dye is characterized by non-monotonic solvatochromism, a strongly polar charge transfer excited state, a large Stokes' shift, a high fluorescence quantum yield and a high fluorescence lifetime...
October 31, 2017: Organic & Biomolecular Chemistry
https://www.readbyqxmd.com/read/29038592/in-vivo-imaging-of-lung-inflammation-with-neutrophil-specific-68-ga-nano-radiotracer
#18
Juan Pellico, Ana V Lechuga-Vieco, Elena Almarza, Andrés Hidalgo, Cristina Mesa-Nuñez, Irene Fernández-Barahona, Juan A Quintana, Juan Bueren, Jose A Enríquez, Jesús Ruiz-Cabello, Fernando Herranz
In vivo detection and quantification of inflammation is a major goal in molecular imaging. Furthermore, cell-specific detection of inflammation would be a tremendous advantage in the characterization of many diseases. Here, we show how this goal can be achieved through the synergistic combination of nanotechnology and nuclear imaging. One of the most remarkable features of this hybrid approach is the possibility to tailor the pharmacokinetics of the nanomaterial-incorporated biomolecule and radionuclide. A good example of this approach is the covalent binding of a large amount of a neutrophil-specific, hydrophobic peptide on the surface of (68)Ga core-doped nanoparticles...
October 16, 2017: Scientific Reports
https://www.readbyqxmd.com/read/29036365/the-developmental-origin-and-compartmentalization-of-glutathione-s-transferase-omega-2-isoforms-in-the-perinuclear-theca-of-eutherian-spermatozoa
#19
Lauren E Hamilton, Genevieve Acteau, Wei Xu, Peter Sutovsky, Richard Oko
The perinuclear theca (PT) is a condensed, nonionic detergent resistant cytosolic protein layer encapsulating the sperm head nucleus. It can be divided into two regions: the subacrosomal layer, whose proteins are involved in acrosomal assembly during spermiogenesis, and the postacrosomal sheath (PAS), whose proteins are implicated in sperm-oocyte interactions during fertilization. In continuation of our proteomic analysis of the PT, we have isolated two prominent PT-derived proteins of 28 and 31 kDa from demembranated bovine sperm head fractions...
October 1, 2017: Biology of Reproduction
https://www.readbyqxmd.com/read/29036327/measurement-of-incorporation-kinetics-of-non-fluorescent-native-nucleotides-by-dna-polymerases-using-fluorescence-microscopy
#20
Matthew T Walsh, Xiaohua Huang
We describe a method for measuring the single-turnover incorporation kinetics of non-fluorescent native nucleotides by DNA polymerases. Time-lapse total internal reflection fluorescence (TIRF) microscopy is used to directly measure the kinetics of single-base nucleotide incorporation into primed DNA templates covalently attached to the surface of a glass coverslip using a fixed ratio of a native nucleotide and a corresponding fluorescently labeled nucleotide over a series of total nucleotide concentrations...
September 19, 2017: Nucleic Acids Research
keyword
keyword
56238
1
2
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read
×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"