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Ek Raj Thapaliya, Yang Zhang, Pravat Dhakal, Adrienne S Brown, James N Wilson, Kevin Collins, Françisco M Raymo
Seven macromolecular constructs incorporating multiple borondipyrromethene (BODIPY) fluorophores along a common poly(methacrylate) backbone with decyl and oligo(ethylene glycol) side chains were synthesized. The hydrophilic oligo(ethylene glycol) components impose solubility in aqueous environment on the overall assembly. The hydrophobic decyl chains insulate effectively the fluorophores from each other to prevent detrimental interchromophoric interactions and preserve their photophysical properties. As a result, the brightness of these multicomponent assemblies is approximately three times greater than that of a model BODIPY monomer...
April 21, 2017: Bioconjugate Chemistry
Poushali Das, Madhuparna Bose, Sayan Ganguly, Subhadip Mondal, Amit Kumar Das, Susanta Banerjee, Narayan Chandra Das
Fluorescent carbon dots, zero-dimensional nanomaterials with surface ligands, have been studied extensively over the past few years in biolabelling or fluorescence-based live cell assays. In the past, synthetic organic dyes have been used as cell tracking materials, but they have severe limitations; fluorescent carbon dots may pave the way to biolabelling and cell imaging. In this work, green fluorescent carbon dots have been synthesized from a green source, gram, without any sort of covalent or ionic modifications...
May 12, 2017: Nanotechnology
Mahmoud Roushani, Faezeh Shahdost-Fard
This study describes a high-performance electrochemical aptasensor which is employed to detect Ibuprofen (IBP) as a painkiller drug by using a novel platform as an integrated sensing interface. In order to make the aptasensor, the Den-QD bioconjugate was immobilized on the surface of a GC electrode and followed the Apt was incubated on this surface. The incubation of the IBP on the aptasensor surface and the formation of the Apt/IBP complex, led to a hindered electron transfer reaction on the sensing surface, which decreased the peak current of the redox probe...
June 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
Yang Yang, Zhehan Yang, Jiajia Lv, Ruo Yuan, Yaqin Chai
In this work, a Pt nanoparticles-functionalized Co-based metal organic frameworks (PtNPs@Co(II)MOFs@PtNPs) was synthesized and applied in electrochemical aptasensor for thrombin (TB) detection. First, the Co(II)MOFs@PtNPs were prepared via the mixed solvothermal method, which consists of inner Pt nanoparticles (PtNPs) encapsulated by aminofunctionalized Co(II)MOFs materials. Following that, additional PtNPs were adsorbed on the surface of Co(II)MOFs@PtNPs, resulting in the formation of PtNPs@Co(II)MOFs@PtNPs nanocomposite...
July 1, 2017: Talanta
Matthew Paeth, Jacob Stapleton, Melissa L Dougherty, Henry Fischesser, Jerry Shepherd, Matthew McCauley, Rebecca Falatach, Richard C Page, Jason A Berberich, Dominik Konkolewicz
A series of methods are outlined for attaching functional polymers to proteins. Polymers with good control over structure, functionality, and composition can be created using reversible addition-fragmentation chain transfer (RAFT) polymerization. These polymers can be covalently linked to enzymes and proteins using either the "grafting-to" approach, where a preformed polymer is attached to the protein surface, or the "grafting-from" approach, where the polymer is grown from the protein surface. Methods for grafting-to, or attaching the RAFT chain transfer agent to the protein surface outlined include the commonly used carbodiimide/activated ester (EDC/NHS) coupling...
2017: Methods in Enzymology
Konda R Kunduru, S N Raju Kutcherlapati, Dhamodaran Arunbabu, Tushar Jana
Jack bean urease is an important enzyme not only because of its numerous uses in medical and other fields but also because of its historical significance-the first enzyme to be crystallized and also the first nickel metalloenzyme. This enzyme hydrolyzes urea into ammonia and carbon dioxide; however, the stability of this enzyme at ambient temperature is a bottleneck for its applicability. To improve urease stability, it was immobilized on different substrates, particularly on polymeric hydrogels. In this study, the enzyme was coupled covalently with poly(acrylamide) hydrogel with an yield of 18μmol/cm(3)...
2017: Methods in Enzymology
Yingqian Zhang, Xiaoping Zhou, Yonghui Xie, Marc M Greenberg, Zhen Xi, Chuanzheng Zhou
5-Methylene pyrrolones (5MPs) are highly thiol-specific and tracelessly removable bioconjugation tools. 5MPs are readily prepared from primary amines in one step. 5MPs exhibit significantly improved stability under physiologically relevant conditions and cysteine specificity compared to commonly used analogues, maleimides. Michael addition of thiol to 5MPs occurs rapidly, cleanly, and does not generate a stereocenter. The conjugates efficiently release thiols via retro-Michael reaction in alkaline buffer (pH 9...
April 20, 2017: Journal of the American Chemical Society
Thomas Botzanowski, Stéphane Erb, Oscar Hernandez-Alba, Anthony Ehkirch, Olivier Colas, Elsa Wagner-Rousset, David Rabuka, Alain Beck, Penelope M Drake, Sarah Cianferani
Antibody-drug conjugates (ADCs) have emerged as a family of compounds with promise as efficient immunotherapies. First-generation ADCs were generated mostly via reactions on either lysine side-chain amines or cysteine thiol groups after reduction of the interchain disulfide bonds, resulting in heterogeneous populations with a variable number of drug loads per antibody. In order to control the position and the number of drug loads, new conjugation strategies aiming at the generation of more homogeneous site-specific conjugates have been developed...
April 13, 2017: MAbs
Sobhan Faezi, Ahmad Reza Bahrmand, Mehdi Mahdavi, Seyed Davar Siadat, Soroush Sardari, Iraj Nikokar, Korosh Khanaki, Ebrahim Mirzajani, Gholamreza Goudarzi
Mucoid strains of Pseudomonas aeruginosa are closely associated with chronic pulmonary infections. In this report we describe a straightforward approach to conjugate high molecular weight alginate to type b-flagellin (FLB) and investigation of its bioactivity. The conjugation process was performed by using ADH and EDAC. The endotoxin was eliminated from the candidate vaccine by LPS removal resin followed by LAL test. The bioconjugate molecules were verified by simultaneously determination of polysaccharide/protein content followed by gel filtration chromatography and FTIR spectroscopy...
April 10, 2017: Biologicals: Journal of the International Association of Biological Standardization
Yurong Que, Chun Feng, Guolin Lu, Xiaoyu Huang
Lanthanide-containing nanoparticles (LnNPs), for example, NaYF4, are considered to be one of the most promising platforms for biological and material applications due to their unique and unusual magnetic and upconversion fluorescent properties. However, limited water dispersity, low long-term colloidal stability, and difficulty in further functionalization greatly narrow the scope of their application in the real world. Herein, we report a facile strategy to counter the aforementioned barriers to the expanding use of LnNPs that involves surface-coating the LnNPs with poly(ethylene glycol)-b-poly(pentafluorophenyl methacrylate)/phosphonic acid and subsequently shell cross-linking with NH2-PEG-NH2...
April 21, 2017: ACS Applied Materials & Interfaces
Isabell Hellmuth, Isabel Freund, Janine Schlöder, Salifu Seidu-Larry, Kathrin Thüring, Kaouthar Slama, Jens Langhanki, Stefka Kaloyanova, Tatjana Eigenbrod, Matthias Krumb, Sandra Röhm, Kalina Peneva, Till Opatz, Helmut Jonuleit, Alexander H Dalpke, Mark Helm
A fundamental mechanism of the innate immune system is the recognition, via extra- and intracellular pattern-recognition receptors, of pathogen-associated molecular patterns. A prominent example is represented by foreign nucleic acids, triggering the activation of several signaling pathways. Among these, the endosomal toll-like receptor 7 (TLR7) is known to be activated by single-stranded RNA (ssRNA), which can be specifically influenced through elements of sequence structure and posttranscriptional modifications...
2017: Frontiers in Immunology
Jianfang Jiang, Jiaqi Zhao, Chunyang He, Baodong Cui, Jun Xiong, Hao Jiang, Juan Ao, Guangyan Xiang
The use of cellulase hydrolysis of straw to produce fermentable sugars has many application prospects. However, cellulase is very expensive, which hampers its industrial applications. To improve cellulase's catalytic activity and reduce the enzyme cost, magnetite carboxymethyl chitosan/calcium alginate - cellulase bioconjugate (MCCCB) was synthesized via an improved hydrothermal method, molecular self-assembly technology, physical absorption, embedding and covalent bonding. Its loading capacity was 3.95mg/mL, and the catalytic activity increased to 267...
June 15, 2017: Carbohydrate Polymers
Khairujjaman Laskar, Syed Mohd Faisal, Abdul Rauf, Anees Ahmed, Mohammad Owais
Fatty acid functionalized chitosan conjugates are of great interest in cancer therapeutics because of its internalization through receptor mediated endocytosis into the cancer cells. Keeping the above fact into consideration, herein we synthesized the undec-10-enoic acid functionalized chitosan based undecyl-chitosan (U-CS) nano-bioconjugate with the use of DCC as a coupling agent. The U-CS conjugate synthesized was confirmed and characterized by FTIR, (1)H NMR, TGA, XRD, SEM and TEM analysis. Generally, it is well established that conjugates of oleic acid with human Alpha-lactalbumin (HAMLET) induce cytotoxicity in the altered cells, but not in healthy cells...
June 15, 2017: Carbohydrate Polymers
Arianna Gennari, Chirag Gujral, Erwin Hohn, Enrique Lallana, Francesco Cellesi, Nicola Tirelli
This study presents a quantitative assessment of the complexation between boronic acids and diols as a reversible and double-stimulus (oxidation and acidification)-responsive bioconjugation reaction. First, by using a competition assay, we have evaluated the equilibrium constants (water, pH 7.4) of 34 boronate/diol pairs, using diols of both aliphatic and aromatic (catechols) nature; in general, catechols were characterized by constants 3 orders of magnitude higher than those of aliphatic diols. Second, we have demonstrated that successful complexation with diols generated in situ via enzymatic reactions, and the boronate complexation was also employed to calculate the Michaelis-Menten parameters for two catechol-producing reactions: the demethylation of 3-methoxytyramine and the 2-hydroxylation of estradiol, respectively, mediated by P4502D6 and P4501A2...
April 18, 2017: Bioconjugate Chemistry
Hejia Henry Wang, Burcin Altun, Kido Nwe, Andrew Tsourkas
Protein bioconjugation has been a crucial tool for studying biological processes and developing therapeutics. Sortase A (SrtA), a bacterial transpeptidase, has become widely used for its ability to site-specifically label proteins with diverse functional moieties, but a significant limitation is its poor reaction kinetics. In this work, we address this by developing proximity-based sortase-mediated ligation (PBSL), which improves the ligation efficiency to over 95 % by linking the target protein to SrtA using the SpyTag-SpyCatcher peptide-protein pair...
April 4, 2017: Angewandte Chemie
Saumya Roy, Jun Y Axup, Jane S Forsyth, Rajib K Goswami, Benjamin M Hutchins, Krishna M Bajuri, Stephanie A Kazane, Vaughn V Smider, Brunhilde H Felding, Subhash C Sinha
Cell-targeting conjugates of Saporin 6, a ribosome inactivating protein (RIP), were prepared using the Saporin Ala 157 Cys mutant, a small molecule inhibitor (SMI) of integrins αvβ3/αvβ5, and a potent cytotoxin, auristatin F (AF). The conjugates selectively and potently inhibited proliferation of tumor cells expressing the target integrins. We anticipate that the small molecule-RIP bioconjugate approach can be broadly applied using other small molecule drugs.
April 11, 2017: Chemical Communications: Chem Comm
Jinny L Liu, Scott A Walper, Kendrick B Turner, Audrey Brozozog Lee, Igor L Medintz, Kimihiro Susumu, Eunkeu Oh, Dan Zabetakis, Ellen R Goldman, George P Anderson
Straightforward and effective methods are required for the bioconjugation of proteins to surfaces and particles. Previously we demonstrated that the fusion of a single domain antibody with the biotin binding molecule rhizavidin provided a facile method to coat biotin-modified surfaces with a highly active and oriented antibody. Here, we constructed similar single domain antibody-rhizavidin fusions as well as unfused rhizavidin with a His-tag. The unfused rhizavidin produced efficiently and its utility for assay development was demonstrated in surface plasmon resonance experiments...
June 2016: Biotechnology Reports
Brigitta Bodnár, Erzsébet Mernyák, Johanna Szabó, János Wölfling, Gyula Schneider, István Zupkó, Zoltán Kupihár, Lajos Kovács
The syntheses of monosaccharide-d-secoestrone conjugates are reported. They were prepared from 3-(prop-2-inyloxy)-d-secoestrone alcohol or oxime and monosaccharide azides via Cu(I)-catalyzed azide-alkyne cycloaddition reactions (CuAAC). The antiproliferative activities of the conjugates were investigated in vitro against a panel of human adherent cancer cell lines (HeLa, A2780 and MCF-7) by means of MTT assays. The protected d-glucose-containing d-secoestrone oxime bioconjugate (24b) proved to be the most effective with an IC50 value in the low micromolar range against A2780 cell line...
May 1, 2017: Bioorganic & Medicinal Chemistry Letters
Vanja Polic, Karine Auclair
Human cytochrome P450 3A4 (CYP3A4) is responsible for the metabolism of the majority of drugs. As such, it is implicated in many adverse drug-drug and food-drug interactions, and is of significant interest to the pharmaceutical industry. This enzyme is known to simultaneously bind multiple ligands and display atypical enzyme kinetics, suggestive of allostery and cooperativity. As well, evidence of a postulated peripheral allosteric binding site has provoked debate around its significance and location. We report the use of bioconjugation to study the significance of substrate binding at the proposed allosteric site and its effect on CYP3A4 activity...
March 29, 2017: Bioconjugate Chemistry
Anne-Lena Bachmann, Henning D Mootz
Chemoselective and regioselective chemical protein labeling is of great importance, yet no current technique is sufficiently general and simple to perform. Protein trans-splicing by split inteins can be used to ligate short tags with chemical labels to either the N or the C terminus of a protein. The CysTag approach exploits split intein fragments without a cysteine fused with such a short tag containing a single cysteine that is easily amenable to selective modification using classical cysteine bioconjugation...
March 23, 2017: Journal of Peptide Science: An Official Publication of the European Peptide Society
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