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Biopolymers

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https://www.readbyqxmd.com/read/29205278/jack-aviv-and-brains-of-children
#1
REVIEW
Angelo A Lamola
Both lead intoxication in early childhood and deficient bilirubin-binding capacity (BBC) of blood in jaundiced neonates indicate risk for brain damage. Zinc protoporphyrin (ZPP) is a biomarker for lead intoxication (PbI) as well as well as for iron deficiency. Under the leadership of Jack Aviv, Aviv Biomedical, Inc. developed robust hematofluorometers for point-of-care assays of ZPP in blood and for the high-affinity BBC of blood. These assays use just drops of whole blood and are simple, fast and inexpensive...
December 4, 2017: Biopolymers
https://www.readbyqxmd.com/read/29205266/amphiphilic-lysine-conjugated-to-tobramycin-synergizes-legacy-antibiotics-against-wild-type-and-multidrug-resistant-pseudomonas-aeruginosa
#2
Yinfeng Lyu, Ronald Domalaon, Xuan Yang, Frank Schweizer
Peptidomimetic modification is a common route of optimization for biologically active peptides. Previous studies in our group have shown that conjugation of amphiphilic tobramycin to other antibacterials enhance their latent outer membrane permeabilizing and efflux blocking activity toward Gram-negative pathogens including Pseudomonas aeruginosa. Herein, we describe the antimicrobial adjuvant properties of amphiphilic lysine ligated to tobramycin. The most potent amphiphilic lysine-tobramycin conjugate 3 potentiated the antibacterial efficacy of 8 clinically used antibiotics against wild type, multidrug- and extensively drug-resistant P...
December 4, 2017: Biopolymers
https://www.readbyqxmd.com/read/29178472/enzymatic-degradation-of-hyaluronan-hydrogels-with-different-capacity-for-in-situ-bio-mineralization
#3
Liyang Shi, Yu Zhang, Dmitri Ossipov
In situ cross-linked hyaluronan (HA) hydrogels with different capacities for biomineralization were prepared and their enzymatic degradation was monitored. Covalent incorporation of bisphosphonates (BPs) into HA hydrogel results in the increased stiffness of the hydrogel in comparison with the unmodified HA hydrogel of the same cross-linking density. The rate of enzymatic degradation of HABP hydrogel was significantly lower than the rate of degradation of control HA hydrogel in vitro. This effect is observed only in the presence of calcium ions that strongly bind to the matrix-anchored BP groups and promote further mineralization of the matrix...
November 27, 2017: Biopolymers
https://www.readbyqxmd.com/read/29178262/selective-detection-of-%C3%AE-4%C3%AE-1-integrin-vla-4-expressing-cells-using-peptide-functionalized-nanostructured-materials-mimicking-endothelial-surfaces-adjacent-to-inflammatory-sites
#4
Rossella De Marco, Arianna Greco, Natalia Calonghi, Samantha D Dattoli, Monica Baiula, Santi Spampinato, Pierre Picchetti, Luisa De Cola, Michele Anselmi, Francesca Cipriani, Luca Gentilucci
Persistent accumulation of immune cells mediated by α4β1 integrin (VLA-4) is a hallmark of the inflammatory diseases and of chronic inflammation observed in the affected tissues of autoimmune diseases. Aiming at exploring new methods for monitoring the course of the inflammatory processes, we designed the first peptide-functionalized nanostructured devices capable to mimic the high-density multivalency binding between the α4β1 integrin-expressing cells and the ligands overexpressed on the endothelial surfaces, in the proximity of the sites of inflammation...
November 27, 2017: Biopolymers
https://www.readbyqxmd.com/read/29178159/crystallographic-insights-into-the-self-assembly-of-klvff-amyloid-beta-peptides
#5
Andrea Pizzi, Valentina Dichiarante, Giancarlo Terraneo, Pierangelo Metrangolo
Amyloidogenic peptide fragment KLVFF (H2 N-Lys-Leu-Val-Phe-Phe-COOH, Aβ16-20 ), the core-sequence of the polypeptide Aβ40, is a well-studied model for amyloid formation. However, due to its low crystallinity, detailed atomic information of KLVFF structure is lacking. Here we report the high-resolution single-crystal X-ray structure of two monohalogenated KLVFF derivatives, KLVFF(I) and KLVFF(Br). The obtained results highlight how halogenation is a good strategy to promote crystallization and facilitate the phase determination of KLVFF(I) and KLVFF(Br) fragments...
November 27, 2017: Biopolymers
https://www.readbyqxmd.com/read/29178143/peptide-modulators-of-rac1-tiam1-protein-protein-interaction-an-alternative-approach-for-cardiovascular-diseases
#6
Alessandro Contini, Nicola Ferri, Raffaella Bucci, Maria Giovanna Lupo, Emanuela Erba, Maria Luisa Gelmi, Sara Pellegrino
Rac1 GTPase interaction with guanine nucleotide exchange factor Tiam1 is involved in several cancer types and cardiovascular diseases. Although small molecules interfering with their protein-protein interaction (PPI) were identified and studied, the ability of small peptides and peptide mimics acting as Rac1/Tiam1 PPI inhibitors has not been yet explored. Using computational alanine scanning (CAS), the "hot" interfacial residues have been determined allowing the design of a small library of putative PPI inhibitors...
November 27, 2017: Biopolymers
https://www.readbyqxmd.com/read/29168553/probing-the-activity-of-a-recombinant-zn2-transporting-p-type-atpase
#7
H Ravishankar, A Barth, M Andersson
P-type ATPase proteins maintain cellular homeostasis and uphold critical concentration gradients by ATP-driven ion transport across biological membranes. Characterization of single-cycle dynamics by time-resolved X-ray scattering techniques in solution could resolve structural intermediates not amendable to for example crystallization or cryo-electron microscopy sample preparation. To pave way for such time-resolved experiments, we used biochemical activity measurements, Attenuated Total Reflectance (ATR) and time-dependent Fourier-Transform Infra-Red (FTIR) spectroscopy to identify optimal conditions for activating a Zn2+ -transporting Type-I ATPase from Shigella sonnei (ssZntA) at high protein concentration using caged ATP...
November 23, 2017: Biopolymers
https://www.readbyqxmd.com/read/29159831/design-and-development-of-low-cost-polyurethane-biopolymer-based-on-castor-oil-and-glycerol-for-biomedical-applications
#8
A C W Tan, B J Polo-Cambronell, E Provaggi, C Ardila-Suárez, G E Ramirez-Caballero, V G Baldovino-Medrano, D M Kalaskar
In the current study, we present the synthesis of novel low cost bio-polyurethane compositions with variable mechanical properties based on castor oil and glycerol for biomedical applications. A detailed investigation of the physicochemical properties of the polymer was carried out by using mechanical testing, ATR-FTIR, and X-ray photoelectron spectroscopy (XPS). Polymers were also tested in short term in-vitro cell culture with human mesenchymal stem cells to evaluate their biocompatibility for potential applications as biomaterial...
November 21, 2017: Biopolymers
https://www.readbyqxmd.com/read/29154500/structure-activity-studies-of-peptidomimetics-based-on-kinase-inhibitory-region-of-suppressors-of-cytokine-signaling-1
#9
Sara La Manna, Laura Lopez-Sanz, Marilisa Leone, Paola Brandi, Pasqualina Liana Scognamiglio, Giancarlo Morelli, Ettore Novellino, Carmen Gomez-Guerrero, Daniela Marasco
Suppressors of Cytokine Signaling (SOCS) proteins are negative regulators of JAK proteins that are receptor-associated tyrosine kinases, which play key roles in the phosphorylation and subsequent activation of several transcription factors named STATs. Unlike the other SOCS proteins, SOCS1 and 3 show, in the N-terminal portion, a small kinase inhibitory region (KIR) involved in the inhibition of JAK kinases. Drug discovery processes of compounds based on KIR sequence demonstrated promising in functional in vitro and in inflammatory animal models and we recently developed a peptidomimetic called PS5, as lead compound...
November 20, 2017: Biopolymers
https://www.readbyqxmd.com/read/29152711/the-burst-phase-folding-intermediate-of-ribonuclease-h-changes-conformation-over-evolutionary-history
#10
Shion A Lim, Susan Marqusee
The amino acid sequence encodes the energy landscape of a protein. Therefore, we expect evolutionary mutations to change features of the protein energy landscape, including the conformations adopted by a polypeptide as it folds to its native state. Ribonucleases H (RNase H) from Escherichia coli and Thermus thermophilus both fold via a partially folded intermediate in which the core region of the protein (helices A-D and strands 4-5) is structured. Strand 1, however, uniquely contributes to the T. thermophilus RNase H folding intermediate (Icore+1 ), but not the E...
November 20, 2017: Biopolymers
https://www.readbyqxmd.com/read/29139109/%C3%AE-cyclodextrin-encapsulated-polyphenols-as-effective-antioxidants
#11
Pritam Roy, Amit Kumar Dinda, Susmitnarayan Chaudhury, Swagata Dasgupta
Formation of dityrosine (DT) cross-linkages in proteins is one of the most widely used markers of oxidative stress. Ribonuclease A (RNase A) has 6 Tyr residues and shows a characteristic DT fluorescence peak upon oxidation in addition to major changes in its secondary structure. DT formation can be prevented by using polyphenols (GA, ECG, and EGCG) which are known to have strong antioxidant activity. However, it has been observed that ECG and EGCG initiate protein oligomerization due to protein-polyphenol cross-linkages...
November 15, 2017: Biopolymers
https://www.readbyqxmd.com/read/29139103/differentiation-potential-of-human-adipose-stem-cells-bioprinted-with-hyaluronic-acid-gelatin-based-bioink-through-microextrusion-and-visible-light-initiated-crosslinking
#12
Shinji Sakai, Hiromi Ohi, Tomoki Hotta, Hidenori Kamei, Masahito Taya
Bioprinting has a great potential to fabricate three-dimensional (3D) functional tissues and organs. In particular, the technique enables fabrication of 3D constructs containing stem cells while maintaining cell proliferation and differentiation abilities, which is believed to be promising in the fields of tissue engineering and regenerative medicine. We aimed to demonstrate the utility of the bioprinting technique to create hydrogel constructs consisting of hyaluronic acid (HA) and gelatin derivatives through irradiation by visible light to fabricate 3D constructs containing human adipose stem cells (hADSCs)...
November 15, 2017: Biopolymers
https://www.readbyqxmd.com/read/29127716/conformational-properties-membrane-interaction-and-antibacterial-activity-of-the-peptaibiotic-chalciporin-a-multitechnique-spectroscopic-and-biophysical-investigations-on-the-natural-compound-and-labeled-analogs
#13
Barbara Biondi, Cristina Peggion, Marta De Zotti, Chiara Pignaffo, Annalisa Dalzini, Marco Bortolus, Simona Oancea, Geta Hilma, Annalisa Bortolotti, Lorenzo Stella, Jens Z Pedersen, Victoria N Syryamina, Yuri D Tsvetkov, Sergei A Dzuba, Claudio Toniolo, Fernando Formaggio
In this work, an extensive set of spectroscopic and biophysical techniques (including FT-IR absorption, CD, 2D-NMR, fluorescence, and CW/PELDOR EPR) was used to study the conformational preferences, membrane interaction, and bioactivity properties of the naturally occurring synthetic 14-mer peptaibiotic chalciporin A, characterized by a relatively low (≈20%), uncommon proportion of the strongly helicogenic Aib residue. In addition to the unlabeled peptide, we gained in-depth information from the study of two labeled analogs, characterized by one or two residues of the helicogenic, nitroxyl radical-containing TOAC...
November 11, 2017: Biopolymers
https://www.readbyqxmd.com/read/29127706/peptide-strand-length-controls-the-energetics-of-self-assembly-and-morphology-of-%C3%AE-sheet-fibrils
#14
Robert P W Davies, Binbin Liu, Steven Maude, Lisa M Carrick, Irina Nyrkova, Tom C McLeish, Sarah A Harris
Self-assembling peptides can be used as versatile, natural, and multifunctional building blocks to produce a variety of well-defined nanostructures, materials and devices for applications in medicine and nanotechnology. Here, we concentrate on the 1D self-assembly of de novo designed Px-2 peptide β-strands into anti-parallel β-sheet tapes and higher order aggregates. We study six members of the Px-2 family, ranging from 3 amino acids (aa) to 13 aa in length, using a range of complementary experimental techniques, computer simulation and theoretical statistical mechanics...
November 11, 2017: Biopolymers
https://www.readbyqxmd.com/read/29127701/release-kinetics-of-somatostatin-from-self-assembled-nanostructured-hydrogels
#15
Uma Rai, Thilini R Thrimawithana, Durga Dharmadana, Celine Valery, Simon A Young
Somatostatin-14 is a native neuropeptide with widespread functions in the body. Self-assembly of somatostatin-14 into amyloid-like nanofibrils has been previously demonstrated in aqueous media. We here hypothesize that the somatostatin nanofibrils can form a stable depot that release monomers in a controlled manner. This study aims to investigate if somatostatin monomers are released from physical hydrogels formed in water and in the presence of electrolytes. The release kinetics of the somatostatin monomers is investigated for the first time...
November 11, 2017: Biopolymers
https://www.readbyqxmd.com/read/29105737/enhanced-tissue-adhesiveness-of-injectable-gelatin-hydrogels-through-dual-catalytic-activity-of-horseradish-peroxidase
#16
Thai Thanh Hoang Thi, Yunki Lee, Seung Bae Ryu, Dai Hai Nguyen, Ki Dong Park
Development of bioadhesives with tunable mechanical strength, high adhesiveness, biocompatibility, and injectability is greatly desirable in all surgeries to replace or complement the sutures and staples. Herein, the dual catalytic activity of horseradish peroxidase is exploited to in situ form the hydroxyphenyl propionic acid-gelatin/thiolated gelatin (GH/GS) adhesive hydrogels including two alternative crosslinks (phenol-phenol and disulfide bonds) with fast gelation (few seconds - several minutes) and improved physicochemical properties...
November 6, 2017: Biopolymers
https://www.readbyqxmd.com/read/29086910/esculentin-1a-derived-peptides-kill-pseudomonas-aeruginosa-biofilm-on-soft-contact-lenses-and-retain-antibacterial-activity-upon-immobilization-to-the-lens-surface
#17
Bruno Casciaro, Debarun Dutta, Maria Rosa Loffredo, Stefania Marcheggiani, Alison M McDermott, Mark Dp Willcox, Maria Luisa Mangoni
Contact lens (CL) wear is a risk factor for development of microbial keratitis, a vision threatening infection of the eye. Adverse events associated with colonization of lenses, especially by the multi-drug resistant and biofilm forming bacterium Pseudomonas aeruginosa remain a major safety issue. Therefore, novel strategies and compounds to reduce the onset of CL-associated ocular infections are needed. Recently, the activity of the frog skin-derived antimicrobial peptide Esc(1-21) and its diastereomer Esc(1-21)-1c was evaluated against both planktonic and sessile forms of this pathogen...
October 31, 2017: Biopolymers
https://www.readbyqxmd.com/read/29076532/the-polypeptide-biophysics-of-proline-alanine-rich-sequences-pas-recombinant-biopolymers-with-peg-like-properties
#18
Joscha Breibeck, Arne Skerra
PAS polypeptides comprise long repetitive sequences of the small L-amino acids proline, alanine and/or serine that were developed to expand the hydrodynamic volume of conjugated pharmaceuticals and prolong their plasma half-life by retarding kidney filtration. Here, we have characterized the polymer properties both of the free polypeptides and in fusion with the biopharmaceutical IL-1Ra. Data from size exclusion chromatography, dynamic light scattering, circular dichroism spectroscopy and quantification of hydrodynamic and polar properties demonstrate that the biosynthetic PAS polypeptides exhibit random coil behavior in aqueous solution astonishingly similar to the chemical polymer poly-ethylene glycol (PEG)...
October 27, 2017: Biopolymers
https://www.readbyqxmd.com/read/29076526/probing-the-dynamics-of-restriction-endonuclease-ngomiv-dna-interaction-by-single-molecule-fret
#19
Marijonas Tutkus, Giedrius Sasnauskas, Danielis Rutkauskas
Many type II restriction endonucleases require two copies of their recognition sequence for optimal activity. Concomitant binding of two DNA sites by such an enzyme produces a DNA loop. Here we exploit single-molecule Förster resonance energy transfer (smFRET) of surface-immobilized DNA fragments to study the dynamics of DNA looping induced by tetrameric endonuclease NgoMIV. We have employed a DNA fragment with two NgoMIV recognition sites and a FRET dye pair such that upon protein-induced DNA looping the dyes are brought to close proximity resulting in a FRET signal...
October 27, 2017: Biopolymers
https://www.readbyqxmd.com/read/29068057/exploring-the-influence-of-hyperthermophilic-protein-ssh10b-on-the-stability-and-conformation-of-rna-by-molecular-dynamics-simulation
#20
Xue Zhang, Qing-Chuan Zheng
The hyperthermophilic Ssh10b from Sulfolobus shibatae is a member of the Sac10b family, which binds RNA in vivo as a physiological substrate, and it has been postulated to play a key role in chromosomal organization in Archaea. Even though the crystal structure of Ssh10b-RNA was resolved successively by X-ray diffraction (Protein Data Bank [PDB] code: 3WBM), the detailed dynamic characteristics of Ssh10b-RNA are still unclear. In this study, molecular dynamics (MDs) simulations at 6 temperatures (300, 350, 375, 400, 450, and 500 K) and molecular mechanics Generalized-Born surface area (MM-GB/SA) free energy calculations were performed to investigate the mechanism of how Ssh10b protects and stabilizes RNA...
October 25, 2017: Biopolymers
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