scholarly journals Self-Assembling Behavior of pH-Responsive Peptide A6K without End-Capping

Molecules ◽  
2020 ◽  
Vol 25 (9) ◽  
pp. 2017
Author(s):  
Peng Zhang ◽  
Fenghuan Wang ◽  
Yuxuan Wang ◽  
Shuangyang Li ◽  
Sai Wen
Keyword(s):  
Self Assembly ◽  
Md Simulation ◽  
Block Structure ◽  
Distribution Model ◽  
Ph Responsive ◽  
Random Coils ◽  
Self Assembling ◽  
C Terminus ◽  
Transmission Electron ◽  
End Capping

A short self-assembly peptide A6K (H2N−AAAAAAK−OH) with unmodified N− and C−terminus was designed, and the charge distribution model of this short peptide at different pH was established by computer simulation. The pH of the solution was adjusted according to the model and the corresponding self-assembled structure was observed using a transmission electron microscope (TEM). As the pH changes, the peptide will assemble into blocks or nanoribbons, which indicates that the A6K peptide is a pH-responsive peptide. Circular dichroism (CD) and molecular dynamics (MD) simulation showed that the block structure was formed by random coils, while the increase in β-turn content contributes to the formation of intact nanoribbons. A reasonable explanation of the self-assembling structure was made according to the electrostatic distribution model and the effect of electrostatic interaction on self-assembly was investigated. This study laid the foundation for further design of nanomaterials based on pH-responsive peptides.

Self Assembling Nanostructured Delivery Vehicles for Biochemically Reactive Pairs

1994 ◽  
Vol 351 ◽  
Author(s):  
Nir Kossovsky ◽  
A. Gelman ◽  
H.J. Hnatyszyn ◽  
E. Sponsler ◽  
G.-M. Chow
Keyword(s):  
Physical Properties ◽  
Self Assembly ◽  
Materials Science ◽  
Technology Development ◽  
Biological Behavior ◽  
X Ray Diffraction ◽  
Self Assembling ◽  
Transmission Electron ◽  
Carbon Ceramic

ABSTRACTIntrigued by the deceptive simplicity and beauty of macromolecular self-assembly, our laboratory began studying models of self-assembly using solids, glasses, and colloidal substrates. These studies have defined a fundamental new colloidal material for supporting members of a biochemically reactive pair.The technology, a molecular transportation assembly, is based on preformed carbon ceramic nanoparticles and self assembled calcium-phosphate dihydrate particles to which glassy carbohydrates are then applied as a nanometer thick surface coating. This carbohydrate coated core functions as a dehydroprotectant and stabilizes surface immobilized members of a biochemically reactive pair. The final product, therefore, consists of three layers. The core is comprised of the ceramic, the second layer is the dehydroprotectant carbohydrate adhesive, and the surface layer is the biochemically reactive molecule for which delivery is desired.We have characterized many of the physical properties of this system and have evaluated the utility of this delivery technology in vitro and in animal models. Physical characterization has included standard and high resolution transmission electron microscopy, electron and x-ray diffraction and ζ potential analysis. Functional assays of the ability of the system to act as a nanoscale dehydroprotecting delivery vehicle have been performed on viral antigens, hemoglobin, and insulin. By all measures at present, the favorable physical properties and biological behavior of the molecular transportation assembly point to an exciting new interdisciplinary area of technology development in materials science, chemistry and biology.

Copolymer Nanoparticles Prepared by Self-Assembly of Poly(ethylene glycol) and Poly-γ-Glutamic Acid and its Characteristics

2013 ◽  
Vol 662 ◽  
pp. 136-139
Author(s):  
Ge Yang ◽  
Ke Shuai Lu ◽  
Xue Yan Su
Keyword(s):  
Ethylene Glycol ◽  
Glutamic Acid ◽  
Size Distribution ◽  
Self Assembly ◽  
Aqueous Media ◽  
Poly Ethylene Glycol ◽  
Polyelectrolyte Complexes ◽  
Self Assembling ◽  
Transmission Electron ◽  
Poly Ethylene

The paper describes the preparation and characterization of novel biodegradable nanoparticles based on self-assembly of poly-gamma-glutamic acid (γ-PGA) and poly(ethylene glycol) (PEG). The nanosystems were stable in aqueous media at low pH conditions. Solubility of the systems was determined by turbidity measurements. The particle size and the size distribution of the polyelectrolyte complexes were identified by dynamic lightscattering and transmission electron microscopy.It was found that the size and size distribution of the nanosystems depends on the concentrations of γ-PGA and PEG solutions and their ratio as well as on the pH of the mixture and the order of addition. The diameter of individual particles was in the range of 30–270 nm. measured by TEM, and the average hydrodynamic diameters were between 130 and 300 nm. These biodegradable, self-assembling stable nanocomplexes might be useful for several biomedical applications.

scholarly journals Biocatalysis of d,l-Peptide Nanofibrillar Hydrogel

Molecules ◽  
2020 ◽  
Vol 25 (13) ◽  
pp. 2995 ◽  
Author(s):  
Tiziano Carlomagno ◽  
Maria C. Cringoli ◽  
Slavko Kralj ◽  
Marina Kurbasic ◽  
Paolo Fornasiero ◽  
...  
Keyword(s):  
Self Assembly ◽  
Solid Phase ◽  
Building Blocks ◽  
Cd Spectroscopy ◽  
Tem Analysis ◽  
Design Rules ◽  
Self Assembling ◽  
Transmission Electron ◽  
Oscillatory Rheometry ◽  
The Many

Self-assembling peptides are attracting wide interest as biodegradable building blocks to achieve functional nanomaterials that do not persist in the environment. Amongst the many applications, biocatalysis is gaining momentum, although a clear structure-to-activity relationship is still lacking. This work applied emerging design rules to the heterochiral octapeptide sequence His–Leu–DLeu–Ile–His–Leu–DLeu–Ile for self-assembly into nanofibrils that, at higher concentration, give rise to a supramolecular hydrogel for the mimicry of esterase-like activity. The peptide was synthesized by solid-phase and purified by HPLC, while its identity was confirmed by 1H-NMR and electrospray ionization (ESI)-MS. The hydrogel formed by this peptide was studied with oscillatory rheometry, and the supramolecular behavior of the peptide was investigated with transmission electron microscopy (TEM) analysis, circular dichroism (CD) spectroscopy, thioflavin T amyloid fluorescence assay, and attenuated total reflectance (ATR) Fourier-transform infrared (FT-IR) spectroscopy. The biocatalytic activity was studied by monitoring the hydrolysis of p-nitrophenyl acetate (pNPA) at neutral pH, and the reaction kinetics followed an apparent Michaelis–Menten model, for which a Lineweaver–Burk plot was produced to determine its enzymatic parameters for a comparison with the literature. Finally, LC–MS analysis was conducted on a series of experiments to evaluate the extent of, if any, undesired peptide acetylation at the N-terminus. In conclusion, we provide new insights that allow gaining a clearer picture of self-assembling peptide design rules for biocatalysis.

scholarly journals Self-Assembly of Au-Fe3O4 Hybrid Nanoparticles Using a Sol–Gel Pechini Method

Molecules ◽  
2021 ◽  
Vol 26 (22) ◽  
pp. 6943
Author(s):  
Jesus G. Ovejero ◽  
Miguel A. Garcia ◽  
Pilar Herrasti
Keyword(s):  
Self Assembly ◽  
Pechini Method ◽  
Sol Gel ◽  
Reaction Times ◽  
Alkaline Media ◽  
Hybrid Nanoparticles ◽  
Self Assembling ◽  
Transmission Electron ◽  
Ir Transmission ◽  
Size And Morphology

The Pechini method has been used as a synthetic route for obtaining self-assembling magnetic and plasmonic nanoparticles in hybrid silica nanostructures. This manuscript evaluates the influence of shaking conditions, reaction time, and pH on the size and morphology of the nanostructures produced. The characterization of the nanomaterials was carried out by transmission electron microscopy (TEM) to evaluate the coating and size of the nanomaterials, Fourier-transform infrared spectroscopy (FT-IR) transmission spectra to evaluate the presence of the different coatings, and thermogravimetric analysis (TGA) curves to determine the amount of coating. The results obtained show that the best conditions to obtain core–satellite nanostructures with homogeneous silica shells and controlled sizes (<200 nm) include the use of slightly alkaline media, the ultrasound activation of silica condensation, and reaction times of around 2 hours. These findings represent an important framework to establish a new general approach for the click chemistry assembling of inorganic nanostructures.

scholarly journals Manipulating the ABCs of self-assembly via low-χ block polymer design

2017 ◽  
Vol 114 (25) ◽  
pp. 6462-6467 ◽  
Author(s):  
Alice B. Chang ◽  
Christopher M. Bates ◽  
Byeongdu Lee ◽  
Carol M. Garland ◽  
Simon C. Jones ◽  
...  
Keyword(s):  
Self Assembly ◽  
Soft Materials ◽  
Block Polymer ◽  
Mesoscale Structure ◽  
Self Assembling ◽  
X Ray Scattering ◽  
Transmission Electron ◽  
Self Consistent Field ◽  
Self Consistent Field Theory ◽  
Triblock Terpolymers

Block polymer self-assembly typically translates molecular chain connectivity into mesoscale structure by exploiting incompatible blocks with large interaction parameters (χij). In this article, we demonstrate that the converse approach, encoding low-χ interactions in ABC bottlebrush triblock terpolymers (χAC≲ 0), promotes organization into a unique mixed-domain lamellar morphology, which we designate LAMP. Transmission electron microscopy indicates that LAMP exhibits ACBC domain connectivity, in contrast to conventional three-domain lamellae (LAM3) with ABCB periods. Complementary small-angle X-ray scattering experiments reveal a strongly decreasing domain spacing with increasing total molar mass. Self-consistent field theory reinforces these observations and predicts that LAMP is thermodynamically stable below a critical χAC, above which LAM3 emerges. Both experiments and theory expose close analogies to ABA′ triblock copolymer phase behavior, collectively suggesting that low-χ interactions between chemically similar or distinct blocks intimately influence self-assembly. These conclusions provide fresh opportunities for block polymer design with potential consequences spanning all self-assembling soft materials.

A water-soluble metal–organic complex array as a multinuclear heterometallic peptide amphiphile that shows unconventional anion dependency in its self-assembly

2016 ◽  
Vol 52 (8) ◽  
pp. 1579-1581 ◽  
Author(s):  
Pradip K. Sukul ◽  
Purnandhu Bose ◽  
Toshiaki Takei ◽  
Omar M. Yaghi ◽  
Ying He ◽  
...  
Keyword(s):  
Self Assembly ◽  
Aqueous Media ◽  
Water Soluble ◽  
Ph Responsive ◽  
Organic Complex ◽  
Peptide Amphiphile ◽  
Short Peptide ◽  
Self Assembling ◽  
Metal Organic Complex ◽  
Metal Organic

Water-soluble metal–organic complex array 1, bearing Ru(ii), Pt(ii) and Rh(iii) complexes at the side residues of the short peptide, exhibits anion and pH-responsive self-assembling behaviours in aqueous media.

scholarly journals Computationally designed peptides for self-assembly of nanostructured lattices

2016 ◽  
Vol 2 (9) ◽  
pp. e1600307 ◽  
Author(s):  
Huixi Violet Zhang ◽  
Frank Polzer ◽  
Michael J. Haider ◽  
Yu Tian ◽  
Jose A. Villegas ◽  
...  
Keyword(s):  
Self Assembly ◽  
Noncovalent Interactions ◽  
Building Blocks ◽  
Covalent Modification ◽  
Amino Acid Sequences ◽  
Peptide Sequence ◽  
Self Assembling ◽  
Transmission Electron ◽  
Wide Range ◽  
Micrometer Scale

Folded peptides present complex exterior surfaces specified by their amino acid sequences, and the control of these surfaces offers high-precision routes to self-assembling materials. The complexity of peptide structure and the subtlety of noncovalent interactions make the design of predetermined nanostructures difficult. Computational methods can facilitate this design and are used here to determine 29-residue peptides that form tetrahelical bundles that, in turn, serve as building blocks for lattice-forming materials. Four distinct assemblies were engineered. Peptide bundle exterior amino acids were designed in the context of three different interbundle lattices in addition to one design to produce bundles isolated in solution. Solution assembly produced three different types of lattice-forming materials that exhibited varying degrees of agreement with the chosen lattices used in the design of each sequence. Transmission electron microscopy revealed the nanostructure of the sheetlike nanomaterials. In contrast, the peptide sequence designed to form isolated, soluble, tetrameric bundles remained dispersed and did not form any higher-order assembled nanostructure. Small-angle neutron scattering confirmed the formation of soluble bundles with the designed size. In the lattice-forming nanostructures, the solution assembly process is robust with respect to variation of solution conditions (pH and temperature) and covalent modification of the computationally designed peptides. Solution conditions can be used to control micrometer-scale morphology of the assemblies. The findings illustrate that, with careful control of molecular structure and solution conditions, a single peptide motif can be versatile enough to yield a wide range of self-assembled lattice morphologies across many length scales (1 to 1000 nm).

scholarly journals Mimicking pollen and spore walls: self-assembly in action

2019 ◽  
Vol 123 (7) ◽  
pp. 1205-1218 ◽  
Author(s):  
Nina I Gabarayeva ◽  
Valentina V Grigorjeva ◽  
Alexey L Shavarda
Keyword(s):  
Self Assembly ◽  
Original Method ◽  
Pollen Grain ◽  
Periplasmic Space ◽  
Self Assembling ◽  
Transmission Electron ◽  
Physico Chemical ◽  
Spore Walls ◽  
Pattern Determination

Abstract Background and Aims Decades of research have attempted to elucidate the underlying developmental mechanisms that give rise to the enormous diversity of pollen and spore exines. The organization of the exine starts with the establishment of an elaborate glycocalyx within which the subsequent accumulation of sporopollenin occurs. Ontogenetic studies using transmission electron microscopy of over 30 species from many different groups have shown that the sequence of structures observed during development of the exine corresponds to the sequence of self-assembling micellar mesophases (including liquid crystals) observed at increasing concentrations of surfactants. This suggested that self-assembly plays an important part in exine pattern determination. Some patterns resembling separate layers of spore and pollen grain walls have been obtained experimentally, in vitro, by self-assembly. However, to firmly establish this idea, columellate and granulate exines, the most widespread forms, needed to be simulated experimentally. Methods We used our original method, preparing mixtures of substances analogous to those known to occur in the periplasmic space of developing microspores, then leaving the mixtures undisturbed for specific periods of time to allow the process of self-assembly to occur. We developed our method further by using new substances analogous to those present in the periplasmic space and performing the experiments in a thin layer, more closely resembling the dimensions of the periplasmic space. Key Results The artificial microstructures obtained from our in vitro self-assembly experiments closely resembled the main types of exines, including tectate–columellate, granulate, alveolate and structureless, and permitted comparison with both developing and mature microspore walls. Compared with the previous attempts, we managed to simulate columellate and granulate exines, including lamellate endexine. Conclusions Our results show that simple physico-chemical interactions are able to generate patterns resembling those found in exines, supporting the idea that exine development in nature involves an interplay between the genome and self-assembly.

Combinatorial Approach to Materials Fabrication from Higher Hierarchies of Rosette Nanotubes

2007 ◽  
Vol 1057 ◽  
Author(s):  
Grigory Tikhomirov ◽  
Hicham Fenniri
Keyword(s):  
Electron Microscopy ◽  
Self Assembly ◽  
The Self ◽  
Combinatorial Approach ◽  
X Ray ◽  
Force Microscopy ◽  
Rosette Nanotubes ◽  
Self Assembling ◽  
Atomic Force ◽  
Transmission Electron

ABSTRACTThe self-assembly of six self-complimentary Guanine – Cytosine hybrid heterocycles bearing hydrophobic substituents has been studied using combinatorial approach in eight solvents under different conditions. The parameters that were varied include: the structure of the self-assembling module, its concentration, the solvent, temperature, and time of self-assembly. scanning electron microscopy (SEM) was used as a screening tool. A wide variety of interesting morphologies was found. The most interesting structures were studied by atomic force microscopy (AFM), transmission electron microscopy (TEM), dynamic light scattering (DLS), and X-ray powder diffraction (XRD).

scholarly journals Heterotypic Supramolecular Hydrogels Formed by Noncovalent Interactions in Inflammasomes

Molecules ◽  
2020 ◽  
Vol 26 (1) ◽  
pp. 77
Author(s):  
Adrianna N. Shy ◽  
Huaimin Wang ◽  
Zhaoqianqi Feng ◽  
Bing Xu
Keyword(s):  
Self Assembly ◽  
Electrostatic Interactions ◽  
Structural Information ◽  
Noncovalent Interactions ◽  
Protein Structures ◽  
Peptide Sequence ◽  
Binding Motifs ◽  
Self Assembling ◽  
Transmission Electron ◽  
Peptide Materials

The advance of structural biology has revealed numerous noncovalent interactions between peptide sequences in protein structures, but such information is less explored for developing peptide materials. Here we report the formation of heterotypic peptide hydrogels by the two binding motifs revealed by the structures of an inflammasome. Specifically, conjugating a self-assembling motif to the positively or negatively charged peptide sequence from the ASCPYD filaments of inflammasome produces the solutions of the peptides. The addition of the peptides of the oppositely charged and complementary peptides to the corresponding peptide solution produces the heterotypic hydrogels. Rheology measurement shows that ratios of the complementary peptides affect the viscoelasticity of the resulted hydrogel. Circular dichroism indicates that the addition of the complementary peptides results in electrostatic interactions that modulate self-assembly. Transmission electron microscopy reveals that the ratio of the complementary peptides controls the morphology of the heterotypic peptide assemblies. This work illustrates a rational, biomimetic approach that uses the structural information from the protein data base (PDB) for developing heterotypic peptide materials via self-assembly.

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