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https://www.readbyqxmd.com/read/29156637/synthesis-and-improved-cross-linking-properties-of-c5-modified-furan-bearing-pnas
#1
Joke Elskens, Alex Manicardi, Valentina Costi, Annemieke Madder, Roberto Corradini
Over the past decades, peptide nucleic acid/DNA (PNA:DNA) duplex stability has been improved via backbone modification, often achieved via introducing an amino acid side chain at the α- or γ-position in the PNA sequence. It was previously shown that interstrand cross-linking can further enhance the binding event. In this work, we combined both strategies to fine-tune PNA crosslinking towards single stranded DNA sequences using a furan oxidation-based crosslinking method; for this purpose, γ-l-lysine and γ-l-arginine furan-PNA monomers were synthesized and incorporated in PNA sequences via solid phase synthesis...
November 20, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/29134996/photo-cross-linked-perylene-diimide-derivative-materials-as-efficient-electron-transporting-layers-in-inverted-polymer-solar-cells
#2
Yong-Jin Noh, Yu-Jin Choi, Ji-Ho Jeong, Seok-Soon Kim, Kwang-Un Jeong, Seok-In Na
We present an efficient and stable interfacial material based on a water-soluble perylene diimide derivative functionalized with ionic and methacrylate groups (abbreviated as PDIM), which can be stabilized by the photo-polymerization of diacrylate groups at both ends of the side chain in the PDIM. The characteristics of the photo-cross-linked PDIM films were examined using absorption spectra, cyclic voltammetry, work function, and surface morphology. The feasibility of the photo-cross-linked PDIM films as a novel electron transporting layer (ETL) in polymer solar cells (PSCs) was also investigated...
November 14, 2017: Nanoscale
https://www.readbyqxmd.com/read/29105983/radical-copolymerization-of-vinyl-ethers-and-cyclic-ketene-acetals-as-a-versatile-platform-to-design-functional-polyesters
#3
Antoine Tardy, Jean-Claude Honoré, Johanna Tran, Didier Siri, Vianney Delplace, Isabelle Bataille, Didier Letourneur, Josette Perrier, Cendrine Nicoletti, Marc Maresca, Catherine Lefay, Didier Gigmes, Julien Nicolas, Yohann Guillaneuf
For the first time, the free-radical copolymerization of cyclic ketene acetals (CKAs) and vinyl ethers (VEs) was investigated as an efficient, yet simple approach for the preparation of functional aliphatic polyesters. The copolymerization of CKA and VE was first predicted to be quasi-ideal by DFT calculations. The theoretical prediction was experimentally confirmed by the copolymerization of 2-methylene-1,3-dioxepane (MDO) and butyl vinyl ether (BVE), leading to rMDO = 0.73 and rBVE = 1.61. We then illustrated the versatility of this approach by preparing different functional polyesters: (i) copolymers functionalized by fluorescent probes; (ii) amphiphilic copolymers grafted with poly(ethylene glycol) (PEG) side chains able to self-assemble into PEGylated nanoparticles; (iii) antibacterial films active against Gram+ and Gram- bacteria (including a multiresistant strain) and (iv) cross-linked bioelastomers with suitable properties for tissue engineering applications...
November 5, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/29031897/smart-electrical-bi-layers-lipopeptides-novel-peptidic-chains-like-zigzag-map-esterified-with-phospho-glyceride-as-mono-layer-moieties-capable-in-forming-a-meso-sphere-envelop-with-scaffold-ability-to-cellular-impurities
#4
REVIEW
Sami Saadi, Nazamid Saari, Abdulkarim Sabo Mohammed, Hasanah Mohd Ghazali, Farooq Anwar
Cell impurities are an emerging nucleating molecular barriers having the capability in disordering the metabolic chain reactions of proteolysis, glycolysis and lipolysis. Their massive effects induced by copolymer crystal growth in compaction with metal and mineral transients are extended as well as in damaging DNA and mRNA structure motif and other molecular assembly e.g. histones structure unites. Their polycrystalline packing modes, polydispersity and their tendency to surface and interface adhesion prompted us in structuring scaffold biomaterials enriched with biopeptides, layered by phospho-glycerides ester-forms...
October 11, 2017: Journal of Controlled Release: Official Journal of the Controlled Release Society
https://www.readbyqxmd.com/read/28990530/isoform-separation-by-a-mixed-mode-resin-toyopearl-mx-trp-650m
#5
Tsutomu Arakawa
TOYOPEARL particles are cross-linked hydroxylated methacrylic polymers available in different pore and particle sizes. They are conjugated with different ligands to generate ion-exchange, hydrophobic interaction and affinity resins. They have excellent physical and chemical properties. A mixed-mode resin, TOYOPEARL MX-Trp-650M, is made of this particle with tryptophan conjugated via N-terminal amino group and hence has both hydrophobic/aromatic side chain and carboxyl group. In this review, I will summarize the properties of the TOYOPEARL particles and MX-Trp-650M resin and application of this resin for purification of proteins and in some detail the separation of disulfide (SS)-scrambled oligomers of insulin-like growth factor-1 (IGF-1)...
October 9, 2017: Current Protein & Peptide Science
https://www.readbyqxmd.com/read/28962874/formation-and-detection-of-oxidant-generated-tryptophan-dimers-in-peptides-and-proteins
#6
Luke Carroll, David I Pattison, Justin B Davies, Robert F Anderson, Camilo Lopez-Alarcon, Michael J Davies
Free radicals are produced during physiological processes including metabolism and the immune response, as well as on exposure to multiple external stimuli. Many radicals react rapidly with proteins resulting in side-chain modification, backbone fragmentation, aggregation, and changes in structure and function. Due to its low oxidation potential, the indole ring of tryptophan (Trp) is a major target, with this resulting in the formation of indolyl radicals (Trp(•)). These undergo multiple reactions including ring opening and dimerization which can result in protein aggregation...
September 28, 2017: Free Radical Biology & Medicine
https://www.readbyqxmd.com/read/28898504/reversible-dna-protein-cross-linking-at-epigenetic-dna-marks
#7
Shaofei Ji, Hongzhao Shao, Qiyuan Han, Christopher L Seiler, Natalia Y Tretyakova
5-Formylcytosine (5fC) is an endogenous DNA modification frequently found within regulatory elements of mammalian genes. Although 5fC is an oxidation product of 5-methylcytosine (5mC), the two epigenetic marks show distinct genome-wide distributions and protein affinities, suggesting that they perform different functions in epigenetic signaling. A unique feature of 5fC is the presence of a potentially reactive aldehyde group in its structure. Herein, we show that 5fC bases in DNA readily form Schiff-base conjugates with Lys side chains of nuclear proteins in vitro and in vivo...
September 12, 2017: Angewandte Chemie
https://www.readbyqxmd.com/read/28876055/supramolecular-assembly-of-peptide-amphiphiles
#8
Mark P Hendricks, Kohei Sato, Liam C Palmer, Samuel I Stupp
Peptide amphiphiles (PAs) are small molecules that contain hydrophobic components covalently conjugated to peptides. In this Account, we describe recent advances involving PAs that consist of a short peptide sequence linked to an aliphatic tail. The peptide sequence can be designed to form β-sheets among the amino acids near the alkyl tail, while the residues farthest from the tail are charged to promote solubility and in some cases contain a bioactive sequence. In water, β-sheet formation and hydrophobic collapse of the aliphatic tails induce assembly of the molecules into supramolecular one-dimensional nanostructures, commonly high-aspect-ratio cylindrical or ribbonlike nanofibers...
October 17, 2017: Accounts of Chemical Research
https://www.readbyqxmd.com/read/28837839/genetic-and-structural-elucidation-of-capsular-polysaccharides-from-streptococcus-pneumoniae-serotype-23a-and-23b-and-comparison-to-serotype-23f
#9
Neil Ravenscroft, Aneesa Omar, Jason Hlozek, Cesarina Edmonds-Smith, Rainer Follador, Fabio Serventi, Gerd Lipowsky, Michelle M Kuttel, Paola Cescutti, Amirreza Faridmoayer
Streptococcus pneumoniae is a globally important encapsulated human pathogen with approximately 100 different serotypes recognized. Serogroup 23 consists of serotype 23F, present in licensed vaccines, and emerging serotypes 23A and 23B. Here, we report the previously unknown structures of the pneumococcal capsular polysaccharides serotype 23A and 23B determined using genetic analysis, NMR spectroscopy, composition and linkage analysis and Smith degradation (of polysaccharide 23A). The structure of the serotype 23A capsular polysaccharide is: →4)-β-D-Glcp-(1→3)-[[α-L-Rhap-(1→2)]-[Gro-(2→P→3)]-β-D-Galp-(1→4)]-β-L-Rhap-(1→...
August 18, 2017: Carbohydrate Research
https://www.readbyqxmd.com/read/28813684/mimicking-mechanical-response-of-natural-tissues-strain-hardening-induced-by-transient-reticulation-in-lactose-modified-chitosan-chitlac
#10
Michela Cok, Pasquale Sacco, Davide Porrelli, Andrea Travan, Massimiliano Borgogna, Eleonora Marsich, Sergio Paoletti, Ivan Donati
The effect of transient cross-links has been explored on a lactose-modified chitosan, which previously had shown interesting biological features. The presence of galactose side chains and of the polyol spacer resulted particularly appealing for the reticulation by borate ions. The interaction between chitlac and borax was investigated by means of (11)B-NMR while rheology pointed to a marked non-linear behavior depending on the amount of borax added to the system. The presence of limited amount of cross-linking ion led to dilatant behavior when the steady flow curve was measured...
August 13, 2017: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/28772607/preparation-and-characterization-of-polyurethanes-with-cross-linked-siloxane-in-the-side-chain-by-sol-gel-reactions
#11
Hui Zhao, Tong-Hui Hao, Guo-Hua Hu, Dean Shi, Da Huang, Tao Jiang, Qun-Chao Zhang
A series of novel polyurethanes containing cross-linked siloxane in the side chain (SPU) were successfully synthesized through a sol-gel process. The SPU was composed of 0%-20% N-(n-butyl)-3-aminopropyltriethoxysilane (HDI-T) modified hexamethylene diisocynate homopolymer. The effects of HDI-T content on both the structure and properties of SPU were investigated by Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), mechanical properties tests, gel content test, water contact angle measurement and water absorption test...
February 28, 2017: Materials
https://www.readbyqxmd.com/read/28733212/the-peroxyl-radical-induced-oxidation-of-escherichia-coli-ftsz-and-its-single-tryptophan-mutant-y222w-modifies-specific-side-chains-generates-protein-cross-links-and-affects-biological-function
#12
Elizabeth Escobar-Álvarez, Fabian Leinisch, Gissela Araya, Octavio Monasterio, Lasse G Lorentzen, Eduardo Silva, Michael J Davies, Camilo López-Alarcón
FtsZ (filamenting temperature-sensitive mutant Z) is a key protein in bacteria cell division. The wild-type Escherichia coli FtsZ sequence (FtsZwt) contains three tyrosine (Tyr, Y) and sixteen methionine (Met, M) residues. The Tyr at position 222 is a key residue for FtsZ polymerization. Mutation of this residue to tryptophan (Trp, W; mutant Y222W) inhibits GTPase activity resulting in an extended time in the polymerized state compared to FtsZwt. Protein oxidation has been highlighted as a determinant process for bacteria resistance and consequently oxidation of FtsZwt and the Y222W mutant, by peroxyl radicals (ROO•) generated from AAPH (2,2'-azobis(2-methylpropionamidine) dihydrochloride) was studied...
July 18, 2017: Free Radical Biology & Medicine
https://www.readbyqxmd.com/read/28717933/a-novel-ms-cleavable-azo-cross-linker-for-peptide-structure-analysis-by-free-radical-initiated-peptide-sequencing-frips
#13
Claudio Iacobucci, Christoph Hage, Mathias Schäfer, Andrea Sinz
The chemical cross-linking/mass spectrometry (MS) approach is a growing research field in structural proteomics that allows gaining insights into protein conformations. It relies on creating distance constraints between cross-linked amino acid side chains that can further be used to derive protein structures. Currently, the most urgent task for designing novel cross-linking principles is an unambiguous and automated assignment of the created cross-linked products. Here, we introduce the homobifunctional, amine-reactive, and water soluble cross-linker azobisimidoester (ABI) as a prototype of a novel class of cross-linkers...
October 2017: Journal of the American Society for Mass Spectrometry
https://www.readbyqxmd.com/read/28690007/bioreactor-induced-mesenchymal-progenitor-cell-differentiation-and-elastic-fiber-assembly-in-engineered-vascular-tissues
#14
Shigang Lin, Kibret Mequanint
In vitro maturation of engineered vascular tissues (EVT) requires the appropriate incorporation of smooth muscle cells (SMC) and extracellular matrix (ECM) components similar to native arteries. To this end, the aim of the current study was to fabricate 4mm inner diameter vascular tissues using mesenchymal progenitor cells seeded into tubular scaffolds. A dual-pump bioreactor operating either in perfusion or pulsatile perfusion mode was used to generate physiological-like stimuli to promote progenitor cell differentiation, extracellular elastin production, and tissue maturation...
September 1, 2017: Acta Biomaterialia
https://www.readbyqxmd.com/read/28654756/hydrogels-with-a-memory-dual-responsive-organometallic-poly-ionic-liquid-s-with-hysteretic-volume-phase-transition
#15
Kaihuan Zhang, Xueling Feng, Chongnan Ye, Mark A Hempenius, G Julius Vancso
We report on the synthesis and structure-property relations of a novel, dual-responsive organometallic poly(ionic liquid) (PIL), consisting of a poly(ferrocenylsilane) backbone of alternating redox-active, silane-bridged ferrocene units and tetraalkylphosphonium sulfonate moieties in the side groups. This PIL is redox responsive due to the presence of ferrocene in the backbone and also exhibits a lower critical solution temperature (LCST)-type thermal responsive behavior. The LCST phase transition originates from the interaction between water molecules and the ionic substituents and shows a concentration-dependent, tunable transition temperature in aqueous solution...
July 26, 2017: Journal of the American Chemical Society
https://www.readbyqxmd.com/read/28636365/sustainable-elastomers-from-renewable-biomass
#16
Zhongkai Wang, Liang Yuan, Chuanbing Tang
Sustainable elastomers have undergone explosive growth in recent years, partly due to the resurgence of biobased materials prepared from renewable natural resources. However, mounting challenges still prevail: How can the chemical compositions and macromolecular architectures of sustainable polymers be controlled and broadened? How can their processability and recyclability be enabled? How can they compete with petroleum-based counterparts in both cost and performance? Molecular-biomass-derived polymers, such as polymyrcene, polymenthide, and poly(ε-decalactone), have been employed for constructing thermoplastic elastomers (TPEs)...
June 21, 2017: Accounts of Chemical Research
https://www.readbyqxmd.com/read/28570824/protein-epitope-mimetics-from-new-antibiotics-to-supramolecular-synthetic-vaccines
#17
Katja Zerbe, Kerstin Moehle, John A Robinson
Protein epitope mimetics provide powerful tools to study biomolecular recognition in many areas of chemical biology. They may also provide access to new biologically active molecules and potentially to new classes of drug and vaccine candidates. Here we highlight approaches for the design of folded, structurally defined epitope mimetics, by incorporating backbone and side chains of hot residues onto a stable constrained scaffold. Using robust synthetic methods, the structural, biological, and physical properties of epitope mimetics can be optimized, by variation of both side chain and backbone chemistry...
June 1, 2017: Accounts of Chemical Research
https://www.readbyqxmd.com/read/28526748/the-sialate-o-acetylesterase-esta-from-gut-bacteroidetes-species-enables-sialidase-mediated-cross-species-foraging-of-9-o-acetylated-sialoglycans
#18
Lloyd S Robinson, Warren G Lewis, Amanda L Lewis
The gut harbors many symbiotic, commensal, and pathogenic microbes that break down and metabolize host carbohydrates. Sialic acids are prominent outermost carbohydrates on host glycoproteins called mucins and protect underlying glycan chains from enzymatic degradation. Sialidases produced by some members of the colonic microbiota can promote the expansion of several potential pathogens (e.g. Clostridium difficile, Salmonella, and Escherichia coli) that do not produce sialidases. O-Acetyl ester modifications of sialic acids help resist the action of many sialidases and are present at high levels in the mammalian colon...
July 14, 2017: Journal of Biological Chemistry
https://www.readbyqxmd.com/read/28507244/inhibition-of-staphylococcus-aureus-cell-wall-biosynthesis-by-desleucyl-oritavancin-a-quantitative-peptidoglycan-composition-analysis-by-mass-spectrometry
#19
James D Chang, Erin E Foster, Aanchal N Thadani, Alejandro J Ramirez, Sung Joon Kim
Oritavancin is a lipoglycopeptide antibiotic that exhibits potent activities against vancomycin-resistant Gram-positive pathogens. Oritavancin differs from vancomycin by a hydrophobic side chain attached to the drug disaccharide, which forms a secondary binding site to enable oritavancin binding to the cross-linked peptidoglycan in the cell wall. The mode of action of secondary binding site was investigated by measuring the changes in the peptidoglycan composition of Staphylococcus aureus grown in the presence of desleucyl-oritavancin at subinhibitory concentration using liquid chromatography-mass spectrometry (LC-MS)...
August 1, 2017: Journal of Bacteriology
https://www.readbyqxmd.com/read/28506526/molecular-simulation-and-biochemical-studies-support-an-elevator-type-transport-mechanism-in%C3%A2-eiic
#20
LETTER
Jumin Lee, Zhenning Ren, Ming Zhou, Wonpil Im
Enzyme IIC (EIIC) is a membrane-embedded sugar transport protein that is part of the phosphoenolpyruvate-dependent phosphotransferases. Crystal structures of two members of the glucose EIIC superfamily, bcChbC in the inward-facing conformation and bcMalT in the outward-facing conformation, were previously solved. Comparing the two structures led us to the hypothesis that sugar translocation could be achieved by an elevator-type transport mechanism in which a transport domain binds to the substrate and, through rigid body motions, transports it across the membrane...
June 6, 2017: Biophysical Journal
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