Read by QxMD icon Read


Santosh R Alluri, Patrick J Riss
A variety of substituted non-racemic aziridine-2-carboxylates equivalent to amino acids were prepared and subjected to ring opening reaction by [18F/19F]fluoride. The regio and stereospecific ring opening depends on the substituents on the nitrogen as well as both the carbons of aziridines. The applicability of the methods to afford access to 3-[18F/19F]fluoro amino acids are illustrated.
March 16, 2018: Organic & Biomolecular Chemistry
Tom H Wright, Benjamin G Davis
Methods for installing natural and unnatural amino acids and their modifications into proteins in a benign and precise manner are highly sought-after in protein science. Here we describe a protocol for 'post-translational mutagenesis' that enables the programmed installation of protein side chains through the use of rapid, mild and operationally simple free-radical chemistry performed on recombinantly expressed and purified proteins. By introduction of protein dehydroalanine (Dha) residues (in this instance, from a unique cysteine residue introduced by site-directed mutagenesis) as free-radical trapping 'tags' for downstream modification, exquisite control over the site of subsequent modification is achieved...
October 2017: Nature Protocols
Sonya K Adas, Vinay Bharadwaj, Yang Zhou, Jiuhong Zhang, Alexander J Seed, Nicola Elizabeth Brasch, Paul Sampson
Trifluoromethanesulphonylhydroxamic acid, CF3SO2NHOH, is shown to release HNO under physiological pH conditions. A two-step synthesis is presented with the first complete characterization of CF3SO2NHOH. This molecule rapidly decomposes in neutral aqueous solution to cleanly release HNO and CF3SO2-, demonstrated using the HNO traps TXPTS and HOCbl, and by 19F NMR spectroscopy.
March 11, 2018: Chemistry: a European Journal
Faidad Khan, Mohsin Ahmad Khan, Nadeem Ahmed, Muhammad Islam Khan, Hamid Bashir, Saad Tahir, Ahmad Usman Zafar
INTRODUCTION: Pakistan has one of the highest burdens of pneumococcal diseases in the world, but unfortunately studies in this demanding research area are limited in the region. Pneumococcal surface protein A (PspA) is the next generation pneumococcal vaccine candidate as the protein locates on the Streptococcus pneumoniae surface. Its gene, pspA, might be encoded by all pneumococci, and the protein has proven immunogenicity. The molecular characterization of PspA, pneumococcal serotype distribution and antibiotic susceptibility are important for regional diversity studies...
March 9, 2018: Infectious Diseases and Therapy
Idan Ashur, Hyla Allouche-Arnon, Amnon Bar-Shir
Inorganic nanocrystals (NCs) have been extensively developed for a variety of uses. The ability to obtain high-resolution NMR signals from the core nuclei of NCs in solution could offer new opportunities in materials sciences and MR imaging. Here, we demonstrate that small, water-soluble 19F-ionic NCs can average out homonuclear dipolar interactions, enabling one to obtain high-resolution 19F-NMR signals in solution that reflect the MR properties of F- in the crystal core. Decorating 19F-NC surfaces with a biocompatible polyethylene-glycol coating maintains colloidal stability in water while preserving the NC high-resolution 19F-NMR properties, even after further functionalization...
March 8, 2018: Angewandte Chemie
Miriding Mutailipu, Min Zhang, Bingbing Zhang, Liying Wang, Zhihua Yang, Xin Zhou, Shilie Pan
Fluorooxoborates, benefiting from the large optical band gap, high anisotropy, and ever-greater possibility to form noncentrosymmetric structures activated by the large polarization of the [BOxF4-x](x+1)- building blocks, have been considered as the new fertile fields for searching the ultraviolet (UV) and deep-UV nonlinear optical (NLO) materials. Here, we report the first asymmetric alkaline-earth metal fluorooxoborate SrB5O7F3, which is rationally designed by taking the classic Sr2Be2B2O7 (SBBO) as a maternal structure...
March 2, 2018: Angewandte Chemie
Yasuo Ohkoshi, Toyotaka Sato, Takayuki Wada, Yukari Fukushima, Hiromi Murabayashi, Yasunari Takakuwa, Kaoru Nishiyama, Hiroyuki Honda, Tsukasa Shiraishi, Koji Kuronuma, Hiroki Takahashi, Chie Nakajima, Yasuhiko Suzuki, Shin-Ichi Yokota
Multidrug-resistant Streptococcus pneumoniae strains were isolated from blood and sputum of a patient with disseminated intravascular coagulation in Sapporo city, Japan. These antibiograms were only susceptible to vancomycin, linezolid, daptomycin, some carbapenems, and some fluoroquinolones. Identical antibiograms, serotypes (19F), and sequence types (ST10017) suggested a shared origin of these isolates. Only one ST10017 strain has been isolated in the same city in Japan previously (2014), and the 2014 isolate is still susceptible to macrolides...
February 26, 2018: Journal of Infection and Chemotherapy: Official Journal of the Japan Society of Chemotherapy
Lakshmipriya Anamalagundam, Madhusudan Chaudhary, Santosh Mogurampelly, Michael L Klein, Nagarajarao Suryaprakash
The conformational stability of synthesized diphenyloxalohydrazide and dibenzoyloxalohydrazide fluoro derivatives have been investigated by extensive NMR studies that are ascertained by various levels of theoretical calculations. Two-dimensional 1H-19F HOESY NMR experiments revealed the close spatial proximity between two NMR active nuclei confirming the hydrogen bond mediated interaction between them, further aiding in establishing the probable stable conformations of these molecules. The relaxed potential energy scan disclosed the energy minimized most stable structure among the possible several multiple conformations, which is in concurrence with NMR interpretations...
February 28, 2018: Journal of Physical Chemistry. A
Matthias Roos, Tuo Wang, Alexander A Shcherbakov, Mei Hong
Internuclear distances measured using NMR provide crucial constraints of three-dimensional structures, but are often restricted to about 5 Å due to the weakness of nuclear-spin dipolar couplings. For studying macromolecular assemblies in biology and materials science, distance constraints beyond 1 nm will be extremely valuable. Here we present an extensive and quantitative analysis of the feasibility of 19F spin exchange NMR for precise and robust measurements of inter-atomic distances to 1.6 nm at a magnetic field of 14...
February 27, 2018: Journal of Physical Chemistry. B
Corinna Kohlmeyer, Maike Klüppel, Gerhard Hilt
The electrophilic ipso-substitution of trimethylsilyl-substituted benzene derivatives into nitrosobenzene derivatives is reported. The optimization of the reaction conditions was performed for moderately electron-deficient, electron-rich and sterically hindered starting materials by varying reaction time, temperature and equivalents of NOBF4. Also, a stable intermediate of the nitrosation reaction could be characterized by 19F NMR which can be assigned to a NO+ adduct with the nitrosobenzene derivative. This complex decomposes upon aqueous workup and liberates the desired nitrosobenzene derivative...
February 27, 2018: Journal of Organic Chemistry
Alex J Guseman, Shannon Leigh Speer, Gerardo M Perez Goncalves, Gary J Pielak
Protein-protein interactions are fundamental to biology, yet are rarely studied under physiologically-relevant conditions where the concentration of macromolecules can exceed 300 g/L. These high concentrations cause cosolute-complex contacts that are absent in dilute buffer. Understand-ing such interactions is important because they organize the cellular interior. We used 19F NMR, the dimer-forming A34F variant of the model protein GB1 and the cosolutes bovine serum albumin (BSA) and lysozyme to assess the effects of repulsive and attractive charge-charge dimer-cosolute interac-tions on dimer stability...
February 23, 2018: Biochemistry
Carla Saunders, Mohammed B Khaled, Jimmie D Weaver, Dean J Tantillo
Scaling factors are reported for use in predicting 19F NMR chemical shifts for fluorinated (hetero)aromatic compounds with relatively low levels of theory. Our recommended scaling factors were developed using a curated data set of 52 compounds, with 100 individual 19F shifts spanning a range of 153 ppm. With a maximum deviation of 6.5 ppm between experimental and computed shifts, or 4% of the range tested, these scaling factors allow for the assignment of chemical shifts to specific fluorines in multifluorinated aromatics...
February 22, 2018: Journal of Organic Chemistry
M Nour, A Alaidarous
Bacterial meningitis poses enormous healthcare challenges due to a high mortality, morbidity and sequelae. Neisseria (N.) meningitidis, Haemophilus (H.) influenzae, Streptococcus (S.) pneumoniae and S. agalactiae remain among the most prevalent infectious agents that cause bacterial meningitis in children. The objective of this study was the simultaneous detection of these pathogens in suspected cerebrospinal fluid (CSF) by using multiplex polymerase chain reaction (mPCR) and compare PCR results with standard diagnostics currently used in clinical practice...
February 15, 2018: Current Research in Translational Medicine
Kaile Chen, Xiyan Zhang, Wei Shan, Genming Zhao, Tao Zhang
OBJECTIVE: Thirteen-valent pneumococcal conjugate vaccines (PCV13) was licensed for optional use in mainland China since 2017, but the uptake is low. To update the research evidence for the pneumococcal serotype distribution of pre-PCV era and to estimate the potential impact of PCVs, we performed a meta-analysis on the relevant publications concerning the Chinese population. METHODS: This systematic review and meta-analysis were conducted on the pneumococcal serotype distribution publications in mainland China from 2000 to 2016...
February 16, 2018: Human Vaccines & Immunotherapeutics
Alan C Gibbs, Ruth Steele, Gaohua Liu, Brett A Tounge, Gaetano T Montelione
Dengue virus poses a significant global health threat as the source of increasingly deleterious dengue fever, dengue hemorrhagic fever, and dengue shock syndrome. As no specific antiviral treatment exists for dengue infection, considerable effort is being applied to discover therapies and drugs for maintenance and prevention of these afflictions. The virus is primarily transmitted by mosquitoes, and infection occurs following viral endocytosis by host cells. Upon entering the cell, viral RNA is translated into a large multisubunit polyprotein which is post-translationally cleaved into mature, structural and nonstructural (NS) proteins...
February 21, 2018: Biochemistry
Jennifer R Verani, Sérgio Massora, Sozinho Acácio, Rita Teresa Dos Santos, Delfino Vubil, Fabiana Pimenta, Iaci Moura, Cynthia G Whitney, Maria Helena Costa, Eusébio Macete, Maria Benigna Matsinhe, Maria da Gloria Carvalho, Betuel Sigaúque
Nasopharyngeal carriage is a precursor for pneumococcal disease and can be useful for evaluating pneumococcal conjugate vaccine (PCV) impact. We studied pre-PCV pneumococcal carriage among HIV-infected and -uninfected children in Mozambique. Between October 2012 and March 2013, we enrolled HIV-infected children age <5 years presenting for routine care at seven HIV clinics in 3 sites, including Maputo (urban-south), Nampula (urban-north), and Manhiça (rural-south). We also enrolled a random sample of HIV-uninfected children <5 years old from a demographic surveillance site in Manhiça...
2018: PloS One
Clifford Thomas Gee, Keith E Arntson, Edward J Koleski, Rachel Lynn Staebell, William Charles Krause Pomerantz
Protein-Observed Fluorine NMR Spectroscopy (PrOF NMR) is an emerging technique for screening and characterizing small molecule-protein interactions. The choice of which amino acid to label for PrOF NMR can be critical for analysis. Here we report the first use of a protein containing two different fluoroaromatic amino acids for NMR studies. Using the KIX domain of the CBP/p300 as a model system, we examine ligand binding of several small molecules elaborated from our previous fragment screen and identify a new ligand binding site distinct from those used by native transcription factors...
February 11, 2018: Chembiochem: a European Journal of Chemical Biology
Anna Looser, Christoph Barmet, Thomas Fox, Olivier Blacque, Simon Gross, Jennifer Nussbaum, Klaas P Pruessmann, Roger Alberto
Concurrent magnetic field monitoring in MRI with an array of NMR field probes allows for reducing image imperfections. High 19F concentrations together with short relaxation times are basic probe properties. We present the NMR properties of [Gd(NTf2)4]- dissolved in an ionic liquid consisting of an imidazolium cation and the [NTf2]- anion. These solutions achieve fluorine concentrations as high as 26 M and rapid relaxation times in the sub-ms time range. The second order self-exchange rate of coordinated [NTf2]- with [NTf2]- as determined with [Y(NTf2)4]- is 4...
February 8, 2018: Inorganic Chemistry
Masahiro Chiba, Kazuo Oshimi, Toshihiro Matsukawa, Kouhei Okada, Takuto Miyagishima
A 68-year-old female with smoldering multiple myeloma (IgG-κ type) was admitted to the hospital owing to general fatigue, fever, and pain in the right leg. On the day following admission, she developed shock, and a blood culture revealed Streptococcus pneumoniae. She was diagnosed with septic shock and invasive pneumococcal disease (IPD). She received antibiotics and intravenous immunoglobulin and improved after several days. She had a history of recurrent IPD and had received the pneumococcal polysaccharide vaccine 23 (PPSV23) 2 years earlier...
2018: [Rinshō Ketsueki] the Japanese Journal of Clinical Hematology
Angelique Gajahi-Soudahomme, Aurelie Catan, Pierre Giraud, Sandrine Assouan Kouao, Alexis Guerin-Dubourg, Xavier Debussche, Nathalie Le Moullec, Emmanuel Bourdon, Susana B Bravo, Beatriz Paradela-Dobarro, Ezequiel Alvarez, Olivier Meilhac, Philippe Rondeau, Joel Couprie
The long-acting glucagon-like peptide-1 analogue liraglutide has proven efficiency in the management of type 2 diabetes and also has beneficial effects on cardiovascular diseases. Liraglutide s protracted action highly depends on its capacity to bind to albumin via its palmitic acid part. However, in diabetes, albumin can undergo glycation, resulting in impaired drug binding. Our objective in this study was to assess the impact of human serum albumin (HSA) glycation on liraglutide affinity. Using fluorine labeling of the drug and 19F NMR, we determined HSA affinity for liraglutide in two glycated albumin models...
February 2, 2018: Journal of Biological Chemistry
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"