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Bioconjugate Chemistry | Page 2

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https://read.qxmd.com/read/31319026/site-specific-incorporation-of-a-dithiolane-containing-amino-acid-into-proteins
#21
Minseob Koh, Hyeon-Yeol Cho, Chenguang Yu, Seihyun Choi, Ki-Bum Lee, Peter G Schultz
We have genetically encoded a dithiolane containing amino acid (dtF) in Escherichia coli (E. coli) using a polyspecific aminoacyl-tRNA synthetase (aaRS)/amber suppressor tRNA pair. To demonstrate the utility of dtF for bioapplications, we synthesized gold nanoparticle (AuNP) constructs with a mutant superfolder green fluorescent protein (sfGFP) [sfGFP-AuNP] as a model for the protein-metal conjugation. The resulting sfGFP-AuNP constructs show directional homogeneity and enhanced chemical durability compared to their cysteine analogs towards excess environmental 1,4-dithiothreitol (DTT)...
July 18, 2019: Bioconjugate Chemistry
https://read.qxmd.com/read/31314501/chemically-engineered-synthetic-lipid-vesicles-for-sensing-and-visualization-of-protein-bilayer-interactions
#22
Navneet Dogra, Rajesh Prabhu Balaraman, Punit Kohli
From pathogen intrusion to immune response, cell membrane plays an important role in signal transduction. Such signals are important for cellular proliferation and survival. However, measurement of these subtle signals through the lipid membrane scaffold is challenging. We present a chromatic model membrane vesicle system engineered to covalently bind with lysine residues of protein molecules for investigation of cellular interactions and signaling. We discovered that different protein molecules induced differential spectroscopic signals, which is based on the chemical and physical properties of protein interacting at the vesicle surface...
July 17, 2019: Bioconjugate Chemistry
https://read.qxmd.com/read/31310713/influence-of-lipase-immobilization-mode-on-ethyl-acetate-hydrolysis-in-a-continuous-solid-gas-biocatalytic-membrane-reactor
#23
Giuseppe Vitola, Rosalinda Mazzei, Teresa Poerio, Giuseppe Barbieri, Enrica Fontananova, Dominic Büning, Mathias Ulbricht, Lidietta Giorno
Solid-gas biocatalysis was performed in a specially designed continuous biocatalytic membrane reactor (BMR). In this work, lipase from Candida rugosa (LCR) and ethyl acetate in vapour phase were selected as model enzyme and substrate, respectively, to produce acetic acid and ethanol. LCR was immobilized on functionalized PVDF membranes by using two different kinds of chemical bond: electrostatic and covalent. Electrostatic immobilization of LCR was carried out using a membrane functionalized with amino groups, while covalent immobilization was carried out using membrane, with or without surface-immobilized polyacrylamide (PAAm) microgels, functionalized with aldehyde groups...
July 16, 2019: Bioconjugate Chemistry
https://read.qxmd.com/read/31283212/nanoparticle-size-influences-localized-enzymatic-enhancement-a-case-study-with-phosphotriesterase
#24
Joyce C Breger, Eunkeu Oh, Kimihiro Susumu, William P Klein, Scott A Walper, Mario G Ancona, Igor L Medintz
Enhancements in enzymatic catalytic activity are frequently observed when an enzyme is displayed on a nanoparticle (NP) surface. The exact mechanisms of how this unique interfacial environment gives rise to this phenomenon are still not understood, although evidence suggests that it can help alleviate some of the enzyme's rate-limiting mechanistic steps. The physicochemical limitations that govern when this process arises are also not known including, in particular, the range of NP size and curvature that are associated with it...
July 8, 2019: Bioconjugate Chemistry
https://read.qxmd.com/read/31274300/development-of-a-bioconjugate-platform-for-modifying-the-immune-response-of-autoreactive-cytotoxic-t-lymphocytes-involved-in-type-1-diabetes
#25
Neha Nandedkar-Kulkarni, Abhishek R Vartak, Steven J Sucheck, Katherine A Wall, Anthony Quinn, Michael P Morran, Marcia F McInerney
Type 1 diabetes (T1D) is an autoimmune disorder characterized by autoimmune cell mediated destruction of pancreatic beta cells. Pancreatic beta cells are the only source of insulin in the body. T1D patients then have to depend on insulin injections for their lifetime. Insulin injection can modulate the blood sugar levels, but insulin has little effect on the autoimmune process. Altered peptide ligands (APL) derived from known autoantigens in T1D are able to induce tolerance in autoreactive cells in T1D animal models, but are currently unable to elicit this protection in humans...
July 5, 2019: Bioconjugate Chemistry
https://read.qxmd.com/read/31269795/recent-advances-of-molecular-optical-probes-for-imaging-of-%C3%AE-galactosidase
#26
Jianjian Zhang, Penghui Cheng, Kanyi Pu
β-galactosidase (β-Gal), as a lysosomal hydrolytic enzyme, plays an important physiological role in catalyzing the hydrolysis of glycosidic bonds which convert lactose into galactose. Moreover, upregulation of β-Gal is often correlated with occurrence of primary ovarian cancers and cell senescence. Thereby, detection of β-Gal activity is relevant to cancer diagnosis. Optical imaging possesses high spatial and temporal resolution, high sensitivity, and real-time imaging capability. These properties are beneficial for the detection of β-Gal in living systems...
July 3, 2019: Bioconjugate Chemistry
https://read.qxmd.com/read/31268690/intracellular-delivery-of-luciferase-with-fluorescent-nanodiamonds-for-dual-modality-imaging-of-human-stem-cells
#27
Long-Jyun Su, Hsin-Hung Lin, Meng-Shiue Wu, Lei Pan, Kanchan Yadav, Hsao-Hsun Hsu, Thai-Yen Ling, Yit-Tsong Chen, Huan-Cheng Chang
Delivering functional proteins (such as enzymes) into cells is important in various biological studies and is often accomplished indirectly by transfection with DNA or mRNA encoding recombinant proteins. However, the transfection efficiency of conventional plasmid methods is low for primary cells, which are crucial sources of cell therapy. Here, we present a new platform based on the use of fluorescent nanodiamond (FND) as a biocompatible nanocarrier to enable rapid, effective, and homogeneous labeling of human mesenchymal stem cells (MSCs) with luciferase for multiplex assays and ultrasensitive detection...
July 3, 2019: Bioconjugate Chemistry
https://read.qxmd.com/read/31268689/aggregation-behavior-of-nanoparticle-peptide-systems-affects-autophagy
#28
Santiago Martinez Legaspi, Laura Segatori
The aggregation of nanoparticle colloidal dispersions in complex biological environments changes the nanoparticle properties, such as size and surface area, thus affecting the interaction of nanoparticles at the interface with cellular components and systems. We investigated the effect of nanoparticle aggregation on autophagy, the main catabolic pathway that mediates degradation of nanosized materials and that is activated in response to internalization of foreign nanosized materials. We used carboxylated polystyrene nanoparticles (100 nm) and altered the nanoparticle aggregation behavior through addition of a multidomain peptide, thus generating a set of nanoparticle-peptide mixtures with variable aggregation properties...
July 3, 2019: Bioconjugate Chemistry
https://read.qxmd.com/read/31265254/human-vault-nanoparticle-targeted-delivery-of-antiretroviral-drugs-to-inhibit-human-immunodeficiency-virus-type-1-infection
#29
Jennifer Fulcher, Kyle Tamshen, Alexander L Wollenberg, Valerie Kickhoeffer, Jan Mrazek, Julie Elliott, F Javier Ibarrondo, Peter A Anton, Leonard H Rome, Heather D Maynard, Timothy J Deming, Otto Yang
"Vaults" are ubiquitously expressed endogenous ribonucleoprotein nanoparticles with potential utility for targeted drug delivery. Here we show that recombinant human vault nanoparticles are readily engulfed by certain key human peripheral blood mononuclear cells (PBMC), predominately dendritic cells, monocytes/macrophages, and activated T cells. As these cell types are the primary targets for human immunodeficiency virus type 1 (HIV-1) infection, we examined the utility of recombinant human vaults for targeted delivery of antiretroviral drugs...
July 2, 2019: Bioconjugate Chemistry
https://read.qxmd.com/read/31260272/dual-responsive-micelles-with-aggregation-induced-emission-feature-and-two-photon-aborsption-for-accurate-drug-delivery-and-bioimaging
#30
Tao Yu, Weihua Zhuang, Xin Su, Boxuan Ma, Jun Hu, Haiyang He, Gaocan Li, Yunbing Wang
Intelligent polymeric micelles provide great potential for accurate cancer theranostics. Herein, gemcitabine (GEM)-conjugated redox-responsive prodrug micelles based on a pH-responsive charge-conventional PMPC- b-P (DEMA- co-SS-GEM- co-TPMA) copolymer and a two-photon absorbing aggregation-induced emission (AIE) fluorescence probe have been developed for lysosome-targeted drug release and bioimaging. The multifunctional copolymer has been synthesized via RAFT polymerization, and GEM is conjugated to the copolymer via GSH-cleavable disulfide bonds...
July 1, 2019: Bioconjugate Chemistry
https://read.qxmd.com/read/31259537/understanding-the-chemical-nature-of-nanoparticle-protein-interactions
#31
Didar Baimanov, Rong Cai, Chunying Chen
The formation of a protein corona has been considered a pitfall in the clinical translation of nanomedicines. Hence, interdisciplinary studies on corona characterization are critically essential. A deep understanding of the formation of hard and soft protein coronas upon in vivo administration of nanoparticles is vital. The protein corona gives the nanoplatform a new biological identity. Furthermore, the control of and mechanistic understanding of corona formation as it is regulated by the physicochemical properties of nanoparticles is crucial for developing safe nanomedicines...
July 1, 2019: Bioconjugate Chemistry
https://read.qxmd.com/read/31251583/aryl-sulfate-is-a-useful-motif-for-conjugating-and-releasing-phenolic-molecules-sulfur-fluorine-exchange-click-chemistry-enables-discovery-of-ortho-hydroxy-protected-aryl-sulfate-linker
#32
Suho Park, Sun Young Kim, Jongun Cho, Doohwan Jung, Donghoon Seo, Jaeho Lee, Sangkwang Lee, Sanghyeon Yun, Hyangsook Lee, Okku Park, Beomseok Seo, Sung Ho Woo, Tae Kyo Park
A new self-immolative linker motif, Ortho Hydroxy-Protected Aryl Sulfate (OHPAS), was devised, and OHPAS-containing antibody drug conjugates (ADC) were tested in vitro and in vivo. Conveniently synthesized using Sulfur Fluorine Exchange (SuFEx) chemistry, it is based structurally on diaryl sulfate, with one aryl acting as a payload and the other as a self-immolative sulfate unit having a latent phenol function at the ortho position. The chemically stable OHPAS linker was stable in plasma samples from 5 different species, yet it can release the payload molecule smoothly upon chemical or biological triggering...
June 28, 2019: Bioconjugate Chemistry
https://read.qxmd.com/read/31251559/introduction-of-para-hydroxy-benzyl-spacer-greatly-expands-the-utility-of-ortho-hydroxy-protected-aryl-sulfate-system-application-to-nonphenolic-payloads
#33
Suho Park, Sun Young Kim, Jongun Cho, Doohwan Jung, Donghoon Seo, Jaeho Lee, Sangkwang Lee, Sanghyeon Yun, Hyangsook Lee, Okku Park, Beomseok Seo, Sena Kim, Minah Seol, Sung Ho Woo, Tae Kyo Park
The ortho-hydroxy-protected aryl sulfate (OHPAS) linker is composed of a diaryl sulfate backbone equipped with a latent phenol moiety at the ortho position of one of the aryl units. The Ar-OH released when the ortho phenol undergoes intramolecular cyclization and displaces the second aryl unit can be viewed as a payload. We have shown in the preceding paper that the OHPAS linkers are highly stable chemically and in various plasmas, yet release payloads when exposed to suitable triggering conditions. As an extension of the OHPAS system, we employed a para-hydroxy benzyl (PHB) spacer for coupling to nonphenolic payloads; this tactic again provided a highly stable system capable of smooth release of appended payloads...
June 28, 2019: Bioconjugate Chemistry
https://read.qxmd.com/read/31247138/aptamer-directed-conjugation-of-dna-to-therapeutic-antibodies
#34
Mikkel Bach Skovsgaard, Michael Rosholm Mortensen, Johan Palmfeldt, Kurt Vesterager Gothelf
A method for aptamer directed conjugation of DNA to therapeutic antibodies has been developed. In the method an antibody selective aptamer binds to a specific site in the constant domain of human IgG1 antibodies and is used for both templated and direct conjugation to the antibodies. Through optimization of the design and reaction conditions, the antibody-DNA conjugates could be produced efficiently using equal stoichiometry of protein and DNA. Three dif-ferent antibodies were evaluated, and the conjugates were characterized by anion exchange chromatography and SDS-PAGE...
June 27, 2019: Bioconjugate Chemistry
https://read.qxmd.com/read/31246432/3-fluoro-2-mercuri-6-methylaniline-nucleotide-as-a-high-affinity-nucleobase-specific-hybridization-probe
#35
Asmo Aro-Heinil Auml, Tuomas Lönnberg, Pasi Virta
A 3-fluoro-6-methylaniline nucleoside was synthesized, incorporated into an oligonucleotide and its ability to form mercury-mediated base pairs was studied. UV melting experiments revealed markedly increased duplex stability with thymine, gua-nine and cytosine opposite to the probe and a clear nucleobase-specific binding preference (T > G > C > >A). Moreover, the 3-fluoro group was utilized as a spin label that showed distinct 19F NMR resonance shifts depending on the complementary nucleobase, providing more detailed information on Hg(II)-mediated base pairing...
June 27, 2019: Bioconjugate Chemistry
https://read.qxmd.com/read/31246431/dendrimer-enabled-therapeutic-antisense-delivery-systems-as-innovation-in-medicine
#36
Serge Mignani, Xiangyang Shi, Maria Zablocka, Jean-Pierre Majoral
Antisense oligonucleotide (AON)-based therapies concern the treatment for genetic disorders or infections such as a range of neurodegenerative and neuromuscular diseases and have shown benefits in animal models and patients. Nevertheless, successes in the clinic are still strongly limited by unfavorable biodistribution and poor cellular uptake of AONs. Dendrimer macromolecules are synthetically accessible and consist of a core with repeated iterations (named branches) surrounding this core, and on the periphery functional groups which can be modified for ligand attachment...
June 27, 2019: Bioconjugate Chemistry
https://read.qxmd.com/read/31243978/manipulating-immune-activation-of-macrophages-by-tuning-the-oligonucleotide-composition-of-gold-nanoparticles
#37
Roger M Pallares, Priscilla Choo, Lisa E Cole, Chad A Mirkin, Andrew Lee, Teri W Odom
This paper describes how the ligand shell containing immunostimulatory oligonucleotides surrounding gold nanoparticles affects the in vitro activation of macrophages. Nanoconstructs with similar ligand densities but different oligonucleotide compositions (from 0% to 100% immune-active cytosine-phosphate-guanine, CpG) were compared. Maximum immunostimulation was achieved with CpG content as low as 5% (with total oligonucleotide surface coverage remaining constant), correlating to high levels of antitumor cytokine release and low levels of cancer-promoting ones...
June 19, 2019: Bioconjugate Chemistry
https://read.qxmd.com/read/31243977/kiss-and-run-promoting-effective-and-targeted-cellular-uptake-of-a-drug-delivery-vehicle-composed-of-an-integrin-targeting-diketopiperazine-peptidomimetic-and-a-cell-penetrating-peptide
#38
Lucia Feni, Sara Parente, Clémence Robert, Silvia Gazzola, Daniela Arosio, Umberto Piarulli, Ines Neundorf
Cell-penetrating peptides (CPPs) have emerged as powerful tools in terms of drug delivery. Those short, often cationic peptides are characterized by their usually low toxicity and their ability to transport diverse cargos inside almost any kinds of cells. Still, one major drawback is their nonselective uptake making their application in targeted cancer therapies questionable. In this work, we aimed to combine the power of a CPP (sC18) with an integrin-targeting unit ( c[DKP- f3-RGD]). The latter is composed of the Arg-Gly-Asp peptide sequence cyclized via a diketopiperazine scaffold and is characterized by its high selectivity toward integrin αv β3 ...
June 19, 2019: Bioconjugate Chemistry
https://read.qxmd.com/read/31195795/red-light-triggered-fluorogenic-reaction-with-picomolar-sensitivity-towards-nucleic-acids
#39
Oleksii Zozulia, Tobias Bachmann, Andriy Mokhir
We have previously reported on a red light-triggered, singlet oxygen-mediated fluorogenic reaction that is templated in a highly sequence specific fashion by nucleic acids (S. Dutta, A. Fulop, A. Mokhir, Bioconj. Chem. 2013, 24(9), 1533-1542). Up to date it has remained a single templated reaction responsive to non-toxic >650 nm light. However, it is operative only in the presence of relatively high (> 2 nM) concentrations of templates that dramatically limits its applicability in nucleic acid detection...
June 13, 2019: Bioconjugate Chemistry
https://read.qxmd.com/read/31180651/development-of-theragnostic-tool-using-nir-fluorescence-probe-targeting-mitochondria-in-glioma-cells
#40
Yeonjeong Chu, Min Chul Shin, June Sung, Jongmin Park, Eunha Kim, Sanghee Lee
Because mitochondria are essential organelles for regulating energy homeostasis and intrinsic apoptosis, the perturbation of mitochondrial functions has been considered as an anticancer treatment. In this study, a new near-infrared (NIR) fluorescent probe, SiR-Mito11 was developed as a theragnostic agent for brain tumor by targeting mitochondria. SiR-Mito11 exhibited potential anticancer activity against glioma cells but tolerance in normal neuronal cells. We further confirmed that the selective accumulation of SiR-Mito11 in glioma cells disrupted mitochondria membrane potential, followed by apoptotic cell death...
June 10, 2019: Bioconjugate Chemistry
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