Read by QxMD icon Read


Ivan Andreevich Yaremenko, Gabriel Dos Passos Gomes, Peter Sergeevich Radulov, Yulia Yur'evna Belyakova, Anatoliy Evgen'evich Vilikotskiy, Vera Andreevna Vil', Alexander A Korlyukov, Gennady Ivanovich Nikishin, Igor V Alabugin, Alexander Olegovich Terent'ev
Reactions of 1,5-diketones with H2O2 open an ozone-free approach to ozonides. Bridged ozonides are formed readily at the room temperature in the presence of strong Brønsted or Lewis acids such as H2SO4, p-TsOH, HBF4, or BF3•Et2O. The expected bridged tetraoxanes, the products of double H2O2 addition, were not detected. This procedure is readily scalable to produce gram quantities of the ozonides. Bridged ozonides are stable and can be useful as building block for bioconjugation and further synthetic transformations...
March 13, 2018: Journal of Organic Chemistry
Nicola Salvarese, Barbara Spolaore, Selena Marangoni, Anna Pasin, Alessandro Galenda, Sergio Tamburini, Gianfranco Cicoria, Fiorenzo Refosco, Cristina Bolzati
An assessment study involving the use of the transglutaminase (TGase) conjugation method and the nitride-technetium-99m labelling on a bis(thiosemicarbazone) (BTS) bifunctional chelating agent is presented. The previously described chelator diacetyl-2-(N4 -methyl-3-thiosemicarbazone)-3-(N4 -amino-3-thiosemicarbazone), H2 ATSM/A, has been functionalized with 6-aminohexanoic acid (ε-Ahx) to generate the bifunctional chelating agent diacetyl-2-(N4 -methyl-3-thiosemicarbazone)-3-[N4 -(amino)-(6-aminohexanoic acid)-3-thiosemicarbazone], H2 ATSM/A-ε-Ahx (1), suitable for conjugation to glutamine (Gln) residues of bioactive molecules via TGase...
March 2, 2018: Journal of Inorganic Biochemistry
Huilei Dong, Hongfei Chen, Juqian Jiang, Hui Zhang, Chenxin Cai, Qingming Shen
Sensitive and specific detection of tumor exosomes is of great significance for early cancer diagnosis. In this paper, we report an aptamer strategy for exosome detection based on aptamer recognition-induced multi-DNA release and cyclic enzymatic amplification. First, we use aptamer-magnetic bead bioconjugates to capture tumor exosomes derived from LNCaP cells, leading to the release of three kinds of messenger DNAs (mDNAs). After magnetic separation, the released mDNAs hybridized with the probe DNAs immobilized on a gold electrode...
March 7, 2018: Analytical Chemistry
Pierre Adumeau, Maria Davydova, Brian M Zeglis
Maleimide-bearing bifunctional chelators have been used extensively for the site-selective bioconjugation and radiolabeling of peptides and proteins. However, bioconjugates obtained using these constructs inevitably suffer from limited stability in vivo, a trait which translates into suboptimal activity concentrations in target tissue and higher uptake levels in healthy, non-target tissues. To circumvent this issue, phenyloxadiazolyl methylsulfones have previously been reported as alternatives to maleimides for thiol-based ligations, but these constructs have scarcely been used in the field of radiochemistry...
March 6, 2018: Bioconjugate Chemistry
Ya Wen, Haiqing Dong, Kun Wang, Yan Li, Yongyong Li
Despite of inherent advantages over synthetic polymer based counterparts, protein nanoparticles remain unsatisfactory in fabrication owing to low size control, usage of toxic cross-linker or organic solvents. This partially contributes the marginal benefits of Abraxane® in clinic. Herein, a green synthetic, size controlled approach was developed to generate stable albumin nanoparticles. Physically packed ovalbumin (OVA) nanoclusters were temporally formed in heat, which was then used as the template to form protein nanoparticle chemically stabilized by intermolecular disulfide network...
March 6, 2018: ACS Applied Materials & Interfaces
Hang Zhang, Jinlong Chen, Chunsheng Xiao, Youhua Tao, Xianhong Wang
The growing application of quantum dots (QDs) in biomedical research necessitates, in turn, continuous development of surface functionalizing ligands to optimize their performance for ever more challenging and diverse biological applications. Here, we demonstrate the novel multifunctional polypeptide ligands for compact and biocompatible QDs. The target ligand preparation exploits the efficient, activating agent-free Ugi reaction of four functional components to incorporate lipoic acid, pyridine, zwitterion motifs, and reactive functionalities in a one-pot procedure under mild conditions...
March 5, 2018: Bioconjugate Chemistry
Jian Lv, Qi Zhang, Mao Cai, Yanfang Han, Sanzhong Luo
Aromatic aminocatalysis refers to transformations that employ aromatic amines, such as anilines or aminopyridines, as catalysts. Owing to the conjugation of the amine moiety with the aromatic ring, aromatic amines demonstrate distinctive features in aminocatalysis compared with their aliphatic counterparts. For example, aromatic aminocatalysis typically proceeds with slower turnover, but is more active and conformationally rigid as a result of the stabilized aromatic imine or iminium species. In fact, the advent of aromatic aminocatalysis can be traced back to before the renaissance of organocatalysis in the early 2000s...
March 1, 2018: Chemistry, An Asian Journal
Akhilesh Kumar Shakya, Kutty Selva Nandakumar
Recently, smart biocatalysts, where enzymes are conjugated to stimuli-responsive (smart) polymers, have gained significant attention. Based on the presence or absence of external stimuli, the polymer attached to the enzyme changes its conformation to protect the enzyme from the external environment and regulate the enzyme activity, thus acting as a molecular switch. Owing to this behaviour, smart biocatalysts can be separated easily from a reaction mixture and re-used several times. Several such smart polymer-based biocatalysts have been developed for industrial and biomedical applications...
February 2018: Journal of the Royal Society, Interface
Bernadette Lee, Shuang Sun, Ester Jiménez-Moreno, André A Neves, Gonçalo J L Bernardes
Site-selective protein modification strategies can be used to insert non-natural functional groups into protein structures. Herein, we report on the use of the bis-electrophile 3-bromo-2-bromomethyl-1-propene as a reagent to introduce an electrophilic handle at cysteine residues under mild conditions. This method is demonstrated on a variety of proteins containing a solvent-exposed cysteine residue, including an anti-HER2 nanobody. Chemically distinct protein conjugates are then efficiently formed through further reaction of the electrophilic site with various nucleophiles, including thiols and amines...
February 17, 2018: Bioorganic & Medicinal Chemistry
Maria Matos, Bruno Oliveira, Nuria Martínez-Sáez, Ana Guerreiro, Pedro M S D Cal, Jean Bertoldo, Maria Maneiro, Elizabeth Perkins, Julie Howard, Michael Deery, Justin M Chalker, Francisco Corzana, Gonzalo Jiménez-Osés, Gonçalo J L Bernardes
Site-selective chemical conjugation of synthetic molecules to proteins expands their functional and therapeutic capacity. Current protein modification methods, based on both synthetic and biochemical technologies, can achieve site-selectivity, but these techniques often require extensive sequence engineering or are restricted to the N- or C-terminus. Here we show the computer-assisted design of sulfonyl acrylate reagents for the modification of a single lysine residue on native protein sequences. This feature of the designed sulfonyl acrylates, together with the innate and subtle reactivity differences conferred by the unique local microenvironment surrounding each lysine, contribute to the observed regioselectivity of the reaction...
February 23, 2018: Journal of the American Chemical Society
Francesca Bryden, Camille Martin, Stéphanie Letast, Eva Lles, Inmaculada Viéitez-Villemin, Anaïs Rousseau, Cyril Colas, Marie Brachet-Botineau, Emilie Allard-Vannier, Christel Larbouret, Marie-Claude Viaud-Massuard, Nicolas Joubert
Herein we describe the synthesis and evaluation of four novel HER2-targeting, cathepsin B-sensitive antibody-drug conjugates bearing a monomethylauristatin E (MMAE) cytotoxic payload, constructed via the conjugation of cleavable linkers to trastuzumab using a site-specific bioconjugation methodology. These linkers vary by both cleavable trigger motif and hydrophilicity, containing one of two cathepsin B sensitive dipeptides (Val-Cit and Val-Ala), and engendered with either hydrophilic or hydrophobic character via application of a PEG12 spacer...
February 23, 2018: Organic & Biomolecular Chemistry
Martina Tripepi, Federico Capuana, Eliana Gianolio, Flavio Kock, Amerigo Pagoto, Rachele Stefania, Giuseppe Digilio, Silvio Aime
Molecular imaging requires the specific accumulation of contrast agents at the target. To exploit the superb resolution of MRI for applications in molecular imaging, gadolinium chelates, as the MRI contrast agents (CA), have to be conjugated to a specific vector able to recognize the epitope of interest. Several Gd(III)-chelates can be chemically linked to the same binding vector in order to deliver multiple copies of the CA (multimers) in a single targeting event thus increasing the sensitivity of the molecular probe...
February 22, 2018: Bioconjugate Chemistry
Santosh K Misra, Taylor L Kampert, Dipanjan Pan
Pathogenesis of many cancer is driven by the Myc oncoprotein, its dimerization with Max, and the binding of this heterodimer to E-Boxes of target genes. The systemic effectiveness of potent small molecule inhibitors of Myc-Max dimerization has been lim-ited by poor bioavailability, rapid metabolism, and inadequate target site penetration. The potential of gene therapy for target-ing Myc can be fully realized by successful synthesis of a smart cargo. We developed a 'nuclein' type nanoparticle "siNozyme" (45±5 nm) from nano-assembly of pamitoyl-bio-conjugated acetyl co-enzyme-A for stable incorporation of chemotherapeutics and biologics to achieve remarkable growth inhibition of human melanoma...
February 21, 2018: Bioconjugate Chemistry
Aladin Hamoud, Philippe Barthélémy, Valérie Desvergnes
An N-Heterocyclic Carbene (NHC) catalyzed biomimetic Stetter reaction was applied for the first time as a bioconjugation reaction to sensitive nucleoside-type biomolecules to provide original pyrrole linked nucleolipids. A versatile approach allowed the functionalization of thymidine at the three reactive positions (O-5', O-3' and N-3) providing a structural diversity oriented synthesis. This strategy was applied to the synthesis of an original glyconucleolipid amphiphile in the hope that the pyrrole aromatic moiety would induce additional self-assembling properties...
February 21, 2018: Organic & Biomolecular Chemistry
Katja Hartstock, Benedikt Nilges, Anna Ovcharenko, Nicolas Cornelissen, Nikolai Puellen, Sebastian Leidel, Andrea Rentmeister
m6A is the most abundant internal modification in eukaryotic mRNA. It is introduced by METTL3-METTL14 and tunes mRNA metabolism, impacting cell differentiation and development. Precise transcriptome-wide assignment of m6A sites is of utmost importance. However, m6A does not interfere with Watson-Crick base pairing making polymerase-based detection challenging. We developed a chemical-biology approach for the precise mapping of methyltransferase (MTase) target sites based on the introduction of a bioorthogonal propargyl group in vitro and in cells...
February 20, 2018: Angewandte Chemie
Kenji Watanabe, Takashi Ohshima
A benzylic substitution of 3-indolyl(hydroxyl)acetate derivatives with thiols proceeded specifically in the presence of amino, carboxy, and phosphate groups in weakly acidic aqueous solutions under nearly physiological condition, while no reaction occurred at pH over 7. Kinetic studies revealed that the reaction followed second-order kinetics (first-order in the reactant and first-order in thiol) in contrast with the SN 1 mechanism of common benzylic substitution of alcohols. The utility of the present method for functionalization of biomacromolecules was demonstrated using several model proteins, such as lysozyme, insulin, trypsin, and serum albumin...
February 19, 2018: Chemistry: a European Journal
Anasua Mukhopadhayay, Tarasankar Das, Anindya Datta, Kamendra P Sharma
Solvents particularly those having low-volatility are of great interest for the biocatalytic synthesis of utility chemicals and fuels. Here we show novel and universal solvent-like properties of a neat and water-less polymer surfactant-BSA conjugated material (WL-PSpBSA). This highly viscous, non-volatile material, behaves as a liquid above its solid-liquid transition temperature (≈ 25-27 °C), and can be used as a solvent for variety of completely dry solutes of different sizes, and surface chemistries. We show using a combination of optical microscopy, steady state and time-resolved fluoresence spectroscopy, that dry and powdered dyes (hydrophobic Coumarin 153; C153), enzymes (α-chymotrypsin; α-Chy), or even 2 μm microparticles (diffusion coefficient ca...
February 16, 2018: Biomacromolecules
Shoujun Zhu, Sonia Herraiz, Jingying Yue, Mingxi Zhang, Hao Wan, Qinglai Yang, Zhuoran Ma, Yan Wang, Jiahuan He, Alexander L Antaris, Yeteng Zhong, Shuo Diao, Yi Feng, Ying Zhou, Kuai Yu, Guosong Hong, Yongye Liang, Aaron J Hsueh, Hongjie Dai
Greatly reduced scattering in the second near-infrared (NIR-II) region (1000-1700 nm) opens up many new exciting avenues of bioimaging research, yet NIR-II fluorescence imaging is mostly implemented by using nontargeted fluorophores or wide-field imaging setups, limiting the signal-to-background ratio and imaging penetration depth due to poor specific binding and out-of-focus signals. A newly developed high-performance NIR-II bioconjugate enables targeted imaging of a specific organ in the living body with high quality...
February 15, 2018: Advanced Materials
Laura J Smith, S Maryamdokht Taimoory, Roger Y Tam, Alexander E G Baker, Niema Binth Mohammad, John F Trant, Molly S Shoichet
Engineered hydrogels have been extensively used to direct cell function in 3D cell culture models, which are more representative of the native cellular microenvironment than conventional 2D cell culture. Previously, hyaluronan-furan and bis-maleimide polyethylene glycol hydrogels were synthesized via Diels-Alder chemistry at acidic pH, which did not allow encapsulation of viable cells. In order to enable gelation at physiological pH, the reaction kinetics were accelerated by replacing the hyaluronan-furan with the more electron-rich hyaluronan-methylfuran...
February 14, 2018: Biomacromolecules
Hao He, Christopher B Howard, Yinghui Chen, Shihui Wen, Gungun Lin, Jiajia Zhou, Kristofer J Thurecht, Dayong Jin
Upconversion nanoparticles (UCNPs) are new optical probes for biological applications. For specific biomolecular recognition to be realized for diagnosis and imaging, the key lies in developing a stable and easy-to-use bioconjugation method for antibody modification. Current methods are not yet satisfactory regarding conjugation time, stability, and binding efficiency. Here, we report a facile and high-yield approach based on a bispecific antibody (BsAb) free of chemical reaction steps. One end of the BsAb is designed to recognize methoxy polyethylene glycol-coated UCNPs, and the other end of the BsAb is designed to recognize the cancer antigen biomarker...
February 22, 2018: Analytical 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"