共查询到20条相似文献，搜索用时 0 毫秒
1.
Vengama N. Modepalli Alexandra L. Rodriguez Rui Li Sivapriya Pavuluri Kevin R. Nicholas Colin J. Barrow David R. Nisbet Richard J. Williams 《Peptide Science》2014,102(2):197-205
Nanomaterials are rich in potential, particularly for the formation of scaffolds that mimic the landscape of the host environment of the cell. This niche arises from the spatial organization of a series of biochemical and biomechanical signals. Self‐assembling peptides have emerged as an important tool in the development of functional (bio‐)nanomaterials; these simple, easily synthesized subunits form structures which present the properties of these larger, more complex systems. Scaffolds based upon these nanofibrous matrices are promising materials for regenerative medicine as part of a new methodology in scaffold design where a “bottom‐up” approach is used in order to simulate the native cellular milieu. Importantly, SAPs hold the potential to be bioactive through the presentation of biochemical and biomechanical signals in a context similar to the natural extracellular matrix, making them ideal targets for providing structural and chemical support in a cellular context. Here, we discuss a new methodology for the presentation of biologically relevant epitopes through their effective presentation on the surface of the nanofibers. Here, we demonstrate that these signals have a direct effect on the viability of cells within a three‐dimensional matrix as compared with an unfunctionalized, yet mechanically and morphologically similar system. © 2014 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 102: 197–205, 2014. 相似文献
2.
Chilukuri Subbalakshmi Sunkara V. Manorama Ramakrishnan Nagaraj 《Journal of peptide science》2012,18(5):283-292
The morphology of structures formed by the self‐assembly of short N‐terminal t‐butyloxycarbonyl (Boc) and C‐terminal methyl ester (OMe) protected and Boc‐deprotected hydrophobic peptide esters was investigated. We have observed that Boc‐protected peptide esters composed of either only aliphatic hydrophobic amino acids or aliphatic hydrophobic amino acids in combination with aromatic amino acids, formed highly organized structures, when dried from methanol solutions. Transmission and scanning electron microscopic images of the peptides Boc‐Ile‐Ile‐OMe, Boc‐Phe‐Phe‐Phe‐Ile‐Ile‐OMe and Boc‐Trp‐Ile‐Ile‐OMe showed nanotubular structures. Removal of the Boc group resulted in disruption of the ability to form tubular structures though spherical aggregates were formed. Both Boc‐Leu‐Ile‐Ile‐OMe and H‐Leu‐Ile‐Ile‐OMe formed only spherical nanostructures. Dynamic light scattering studies showed that aggregates of varying dimensions were present in solution suggesting that self‐assembly into ordered structures is facilitated by aggregation in solution. Fourier transform infrared spectroscopy and circular dichroism spectroscopy data show that although all four of the protected peptides adopt well‐defined tertiary structures, upon removal of the Boc group, only H‐Phe‐Phe‐Phe‐Ile‐Ile‐OMe had the ability to adopt β‐structure. Our results indicate that hydrophobic interaction is a very important determinant for self‐assembly and presence of charged and aromatic amino acids in a peptide is not necessary for self‐assembly. Copyright © 2012 European Peptide Society and John Wiley & Sons, Ltd. 相似文献
3.
In keeping with recent efforts to generate compounds for antibiotic and microbicide development, we focused on the creation of non‐natural organo‐peptide hybrids of antimicrobial peptide amides (KLK(L)nKLK‐NH2) derived from sapecin B and a self‐assembling oligoglycine organo‐peptide bolaphile containing an ω‐amino fatty acid residue. The hybrid organo‐peptide bolaphiles with two cationic KLK tripeptide motifs linked with an ω‐amino acid residue (penta‐, octa‐ or undecamethylene chain) maintained the self‐assembling properties of the root oligoglycine bolaphile. Electron microscopy clearly revealed complex supramolecular architectures for both sapecin B‐derived peptides and the hybrid analogues. FT‐IR spectroscopy indicated that the supramolecular structures were composed primarily of β‐sheets. CD revealed that the hybrid bolaphiles did not share the same secondary structures as the sapecin B peptides in solution. However, although secondary structures of antimicrobial peptides are central in the activity, the organo‐peptide bolaphiles also retained the potent antimicrobial activity of the leader sapecin B‐derived peptide against both Gram‐positive and Gram‐negative bacteria. In general, the hybrids were more selective than the sapecin B peptides, as they displayed little or no appreciable haemolytic activity. The results obtained herald a new approach for the design of purpose‐built hybrid organo‐peptide bolaphiles. Copyright © 2013 European Peptide Society and John Wiley & Sons, Ltd. 相似文献
4.
《Peptide Science》2017,108(6)
Short peptides composed of phenylalanine and sequences derived from amyloidogenic peptides have the ability to self‐assemble to form nanostructures including hydrogels. The self‐assembly of peptides composed of only hydrophobic amino acids and aliphatic protecting groups have not been investigated in detail. We have examined various aspects of nanostructures formed by N‐terminal t‐butyloxycarbonyl‐protected aliphatic dipeptide methyl esters dissolved in various solvents. Scanning electron microscopic images indicate that depending on the sequence, position of the amino acid and solvent of dissolution, the peptides self‐assemble into superstructures such as nanotubes and needles particularly from aqueous mixtures of organic solvents. Crystallization was not required for self‐assembly into nanostructures. Circular dichroism and attenuated total internal reflection fourier transform infrared spectroscopy studies indicate that the peptides adopt β‐conformation in the superstructures both in solution and solid state. The nanostructures composed of entirely aliphatic moieties have the ability to bind to aromatic dyes such as Rhodamine 6G, Nile red and Congo red. They also bind to Thioflavin T although the structures do not resemble amyloid fibrils. The powder X‐ray diffraction patterns suggest distinctive packing of the monomers. These structures are stabilized by intermolecular hydrogen bonds and hydrophobic interactions resulting in superstructures containing long distance order and were devoid of hemolytic activity. 相似文献
5.
Evan M. Smoak Melanie P. Dabakis Marsiyana M. Henricus Robert Tamayev Ipsita A. Banerjee 《Journal of peptide science》2011,17(1):14-23
In this work we have probed the interactions of the amyloid Aβ(1–42) peptide with self‐assembled nanospheres. The nanospheres were formed by self‐assembly of a newly developed bolaamphiphile bis(N‐alpha‐amido‐methionine)‐1,8 octane dicarboxylate under aqueous conditions. It was found that the interactions of the Aβ(1–42) peptide with the nanospheres were concentration as well as pH dependent and the peptide largely adopts a random coil structure upon interacting with the nanospheres. Further, upon incorporation with the nanospheres, we observed a relative diminution in the aggregation of Aβ(1–42) at low concentrations of Aβ(1–42). The interactions between the nanospheres and the Aβ(1–42) peptide were investigated by atomic force microscopy, transmission electron microscopy, circular dichroism, FTIR and fluorescence spectroscopy, and the degree of fibrillation in the presence and absence of nanospheres was monitored by the Thioflavine T assay. We believe that the outcome from this work will help further elucidate the binding properties of Aβ peptide as well as designing nanostructures as templates for further investigating the nucleation and fibrillation process of Aβ‐like peptides. Copyright © 2010 European Peptide Society and John Wiley & Sons, Ltd. 相似文献
6.
Matthew D. Shawkey Liliana D'Alba Ming Xiao Matthew Schutte Richard Buchholz 《Journal of morphology》2015,276(4):378-384
Iridescent colors in feathers are some of the brightest in nature, and are produced by coherent light scattering from periodic arrangements of melanosomes (melanin‐containing organelles). Hollow melanosomes, an evolutionary innovation largely restricted to birds, contain an optically powerful combination of high and low refractive indices (from the melanin and air, respectively) that enables production of brighter and more saturated colors than solid melanosomes. However, despite their significance to avian color and potential utility as optical biomaterials, little is known about the ontogeny of either the melanosomes themselves or the nanostructures they comprise. We used light and electron microscopy to characterize nanostructural development in regenerating feathers of wild turkeys, a species with iridescent color produced by a hexagonally close‐packed array of hollow melanosomes. We found that melanosomes form as solid bodies in melanocytes. Later in development, largely after placement in developing barbules, their interiors dissolve and leave hollow cores. These now hollow melanosomes are initially disorganized in the barbule, but become close‐packed as they are pulled to the edge of the barbule, likely through a combination of forces including depletion–attraction. These data suggest that these structurally colored tissues are self‐assembled and represent novel pathways of development. J. Morphol. 276:378–384, 2015. © 2014 Wiley Periodicals, Inc. 相似文献
7.
《Advanced Biosystems》2018,2(3)
Coassembled peptide amphiphile nanofibers designed to target atherosclerotic plaque and enhance cholesterol efflux are shown to encapsulate and deliver a liver X receptor agonist to increase efflux from murine macrophages in vitro. Fluorescence microscopy reveals that the nanofibers, which display an apolipoprotein‐mimetic peptide, localize at plaque sites in low density lipoprotein receptor knockout (LDLR KO) mice with or without the encapsulated molecule, while nanofibers displaying a scrambled, nontargeting peptide sequence do not demonstrate comparable binding. These results show that nanofibers functionalized with apolipoprotein‐mimetic peptides may be effective vehicles for intravascular targeted drug delivery to treat atherosclerosis. 相似文献
8.
The relationship between primary sequence and collagen triple-helix formation is relatively well characterized, while higher levels of structural assembly from these sequences is poorly understood. To address this gap, a new collagen-like triblock peptide design was used to study the relationship between amino acid sequence and supramolecular assembly. Four collagen-like peptides with the sequence (Glu)(5)(Gly-Xaa-Hyp-Gly-Pro-Hyp)(6)(Glu)(5) and corresponding to Xaa = alanine, proline, serine, or valine, and an analogous peptide without the glutamic acid end blocks, were solubilized in water at high concentrations (20-150 mg/mL) and analyzed in optical polarizing microscopy and transmission electron microscopy. Some of the peptides self-assembled into supramolecular structures, the nature of which was determined by the core collagen-like sequence. The globular end blocks appeared necessary for these short triple-helix-forming peptides to spontaneously organize into supramolecular structures in solution and also provided enhanced thermal stability based on CD analysis. The results indicate a strong dependence of the peptide triblock assembly behavior on the identity of the guest residue Xaa; nematic order when Xaa was valine, no organization when Xaa was serine, and banded spherulites displaying a cholesteric-like twist when Xaa was proline or alanine. According to these results, the identity of the amino acid in position Xaa of the triplet Gly-Xaa-Yaa dramatically determined the type of supramolecular assembly formed by short triple helices based on collagen-triblock like sequences. Moreover, the structural organization observed for these collagen-triblock peptides was analogous to some assemblies observed for native collagen in vivo and in vitro. The amino acid sequence in the native collagen proteins may therefore be a direct determinant of the different supramolecular architectures found in connective tissues. 相似文献
9.
Soultan Al‐Halifa Margaryta Babych Ximena Zottig Denis Archambault Steve Bourgault 《Peptide Science》2019,111(1)
Living organisms are an inestimable source of inspiration for the design of biomaterials and nanostructures for medical and technological applications. Amyloids, which were historically associated with diseases, have recently been recognized as a biological structure that performs vital physiological functions in host organisms, highlighting their potential as life‐inspired assemblies. Amyloids are highly organized proteinaceous assemblies characterized by a cross‐β‐sheet quaternary conformation. The mechanical, physical, and biological properties of amyloids suggest that these nanostructures hold great potential as soft materials, nanoparticles, and biomatrices. This potential is associated with many characteristics, including the spontaneous self‐assembly of many polypeptide sequences, high mechanical resistance, biocompatibility, biodegradability as well as thermal, chemical, and enzymatic stability. Moreover, peptide‐based amyloid assemblies can efficiently be obtained by standard solid phase peptide synthesis and orthogonally functionalized with a wide range of biomolecules, such as large proteins and DNA. In this review, after briefly introducing the amyloid structure and the mechanisms of self‐assembly, we describe approaches to identify and design short self‐assembling amyloidogenic peptides. Afterward, we introduce strategies used to functionalize amyloid materials and we highlight some relevant examples in the development of nanovaccines and biosensors. 相似文献
10.
Magnetic resonance imaging (MRI) is one of the most important clinic diagnostic tool used to obtain high‐quality body images. The administration of low‐molecular‐weight Gd complex–based MRI contrast agents (CAs) permits to increase the 1H relaxation rate of nearby water molecules, thus modulating signal intensity and contrast enhancement. Even if highly accurate, MRI modality suffers from its low sensitivity. Moreover, low‐molecular‐weight CAs rapidly equilibrate between the intravascular and extravascular spaces after their administration. In order to improve their sensitivity and limit the extravasation phenomenon, several macromolecular and supramolecular multimeric gadolinium complexes (dendrimers, polymers, carbon nanostructures, micelles, and liposomes) have been designed until now. Because of their biocompatibility, low immunogenicity, low cost, and easy synthetic modification, peptides are attractive building blocks for the fabbrication of novel materials for biomedical applications. We report on the state of the art of supramolecular CAs obtained by self‐assembly of three different classes of building blocks containing a peptide sequence, a gadolinium complex, and, if necessary, a third functional portion achieving the organization process. 相似文献
11.
Emmanouil Kasotakis Estelle Mossou Lihi Adler‐Abramovich Edward P. Mitchell V. Trevor Forsyth Ehud Gazit Anna Mitraki 《Peptide Science》2009,92(3):164-172
The ability to develop a rational basis for the binding of inorganic materials to specific binding sites within self‐assembling biological scaffolds has important applications in nanobiotechnology. Amyloid‐forming peptides are a class of such scaffolds and show enormous potential as templates for the fabrication of low resistance, conducting nanowires. Here we report the use of a self‐assembling peptide building block as scaffold for the systematic introduction of metal‐binding residues at specific locations within the structure. The octapeptide NSGAITIG (Asparagine‐Serine‐Glycine‐Alanine‐Isoleucine‐Threonine‐Isoleucine‐Glycine) from the fiber protein of adenovirus has been identified in previous structural studies as an elementary fibril‐forming building block. Using this building block as a scaffold, we have designed three new cysteine‐containing octa‐peptides to study their eventual fibril‐forming ability and potential templating of metal nanoparticles. We find that the cysteine substitutions do not alter the fibril‐forming potential of the peptides, and that the fibrils formed bind efficiently to silver, gold, and platinum nanoparticles; furthermore, we report unexpected behavior of serine in nucleating gold and platinum nanoparticles. We find that combination of cysteine and serine residues projecting from adjacent sites on a peptide scaffold represents a potentially useful strategy in nucleating inorganic materials. The ability to reliably produce metal‐coated fibrils is a vital first step towards the exploitation of these fibrils as conducting nanowires with applications in nano‐circuitry. Short, biologically inspired self‐assembling peptide scaffolds derived from natural fibrous proteins with known three‐dimensional structure may provide a viable approach towards the rational design of inorganic nanowires. © 2009 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 92: 164–172, 2009. This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com 相似文献
12.
Self‐assembling biological materials increasingly serve as templates for the binding of inorganic materials and fabrication of composite nanowires, tubes, etc. with important applications in nanobiotechnology. We have previously reported the use of a self‐assembling octapeptide building block as scaffold for the systematic introduction of metal‐binding residues, namely cysteines, at the first two amino acids within the sequence (Kasotakis et al., Biopolymers 2009, 92, 164‐172). We have also reported unexpected behavior of serine within the octapeptide NH2 NSGAITIG CONH2 (Asparagine‐Serine‐Glycine‐Alanine‐Isoleucine‐Threonine‐Isoleucine‐Glycine) in nucleating gold and platinum nanoparticles. Herein, we report that this serine residue is instrumental in nucleating silica nanoparticles on the surface of the self‐assembled fibrils from TEOS (tetraethyl orthosilicate) precursors. We carried out a systematic investigation of the adjacent functionalities and we propose that this serine residue is rendered abnormally nucleophilic through proton abstraction by the N‐terminal amino group of the peptide. Peptides with a threonine or a cysteine residue at position 2 are also able to nucleate silica nanoparticles. We propose that rationally designed self‐assembling peptides bearing hydroxyl groups adjacent to free amine functionalities could be used for targeted templating of biogenic and even nonbiogenic oxides. © 2012 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 98: 501–509, 2012. 相似文献
13.
Amyloid‐like aggregation of natural proteins or polypeptides is an important process involved in many human diseases as well as some normal biological functions. Plenty of works have been done on this ubiquitous phenomenon, but the molecular mechanism of amyloid‐like aggregation has not been fully understood yet. In this study, we showed that a series of designer bolaamphiphilic peptides could undergo amyloid‐like aggregation even though they didn't possess typical β‐sheet secondary structure. Through systematic amino acid substitution, we found that for the self‐assembling ability, the number and species of amino acid in hydrophobic section could be variable as long as enough hydrophobic interaction is provided, while different polar amino acids as the hydrophilic heads could change the self‐assembling nanostructures with their aggregating behaviors affected by pH value change. Based on these results, novel self‐assembling models and aggregating mechanisms were proposed, which might provide new insight into the molecular basis of amyloid‐like aggregation. 相似文献
14.
Turgay Kacar Melvin T. Zin Christopher So Brandon Wilson Hong Ma Nevin Gul‐Karaguler Alex K.‐Y. Jen Mehmet Sarikaya Candan Tamerler 《Biotechnology and bioengineering》2009,103(4):696-705
Current biotechnological applications such as biosensors, protein arrays, and microchips require oriented immobilization of enzymes. The characteristics of recognition, self‐assembly and ease of genetic manipulation make inorganic binding peptides an ideal molecular tool for site‐specific enzyme immobilization. Herein, we demonstrate the utilization of gold binding peptide (GBP1) as a molecular linker genetically fused to alkaline phosphatase (AP) and immobilized on gold substrate. Multiple tandem repeats (n = 5, 6, 7, 9) of gold binding peptide were fused to N‐terminus of AP (nGBP1‐AP) and the enzymes were expressed in E. coli cells. The binding and enzymatic activities of the bi‐functional fusion constructs were analyzed using quartz crystal microbalance spectroscopy and biochemical assays. Among the multiple‐repeat constructs, 5GBP1‐AP displayed the best bi‐functional activity and, therefore, was chosen for self‐immobilization studies. Adsorption and assembly properties of the fusion enzyme, 5GBP1‐AP, were studied via surface plasmon resonance spectroscopy and atomic force microscopy. We demonstrated self‐immobilization of the bi‐functional enzyme on micro‐patterned substrates where genetically linked 5GBP1‐AP displayed higher enzymatic activity per area compared to that of AP. Our results demonstrate the promising use of inorganic binding peptides as site‐specific molecular linkers for oriented enzyme immobilization with retained activity. Directed assembly of proteins on solids using genetically fused specific inorganic‐binding peptides has a potential utility in a wide range of biosensing and bioconversion processes. Biotechnol. Bioeng. 2009;103: 696–705. © 2009 Wiley Periodicals, Inc. 相似文献
15.
Self‐assembly of PAs composed of palmitic acid and several repeated heptad peptide sequences, C15H31CO‐(IEEYTKK)n‐NH2 (n = 1–4, represented by PA1–PA4), was investigated systematically. The secondary structures of the PAs were characterized by CD. PA3 and PA4 (n = 3 and 4, respectively) showed an α‐helical structure, whereas PA1 and PA2 (n = 1 and 2, respectively) did not display an α‐helical conformations under the tested conditions. The morphology of the self‐assembled peptides in aqueous medium was studied by transmission electron microscopy. As the number of heptad repeats in the PAs increased, the nanostructure of the self‐assembled peptides changed from nanofibers to nanovesicles. Changes of the secondary structures and the self‐assembly morphologies of PA3 and PA4 in aqueous medium with various cations were also studied. The critical micelle concentrations were determined using a pyrene fluorescence probe. In conclusion, this method may be used to design new peptide nanomaterials. Copyright © 2014 European Peptide Society and John Wiley & Sons, Ltd. 相似文献
16.
17.
Ming Ni Shuangmu Zhuo Ciprian Iliescu Peter T. C. So Jodhbir S. Mehta Hanry Yu Charlotte A. E. Hauser 《Journal of biophotonics》2019,12(12)
Amyloid‐like peptides are an ideal model for the mechanistic study of amyloidosis, which may lead to many human diseases, such as Alzheimer disease. This study reports a strong second harmonic generation (SHG) effect of amyloid‐like peptides, having a signal equivalent to or even higher than those of endogenous collagen fibers. Several amyloid‐like peptides (both synthetic and natural) were examined under SHG microscopy and shown they are SHG‐active. These peptides can also be observed inside cells (in vitro). This interesting property can make these amyloid‐like peptides second harmonic probes for bioimaging applications. Furthermore, SHG microscopy can provide a simple and label‐free approach to detect amyloidosis. Lattice corneal dystrophy was chosen as a model disease of amyloidosis. Morphological difference between normal and diseased human corneal biopsy samples can be easily recognized, proving that SHG can be a useful tool for disease diagnosis. 相似文献
18.
Andrey V Kajava Sergey A Potekhin Giampietro Corradin Richard D Leapman 《Journal of peptide science》2004,10(5):291-297
Self-assembling peptides present attractive platforms for engineering materials with controlled nanostructures. Recently, an alpha-helical fibril forming peptide (alphaFFP) was designed that self-assembles into nanofibrils at acid pH. Circular dichroism spectroscopy, electron-microscopy and x-ray fibre diffraction data showed that the most likely structure of alphaFFP fibrils is a five-stranded coiled coil rope. In the present study, scanning transmission electron microscopy (STEM) was used to improve our understanding of the alphaFFP fibril structure. The measurements of fibril mass per length suggest that there are ten alpha-helices in transverse sections of the fibrils. Based on the known data, it is proposed that a predominant fibrillar structure of alphaFFP is a dimer of alpha-helical five stranded protofilaments wrapped around a common axis. It is shown that these structures have an axial dimension of 58 +/- 16 nm and a width of 4 +/- 1 nm. A small number of thin fibrils is also observed in the negative stained preparation and STEM images. The thin fibrils may correspond to the single protofilament. 相似文献
19.
- Breeding systems of plants determine their reliance on pollinators and ability to produce seeds following self‐pollination. Self‐sterility, where ovules that are penetrated by self‐pollen tubes that do not develop into seeds, is usually considered to represent either a system of late‐acting self‐incompatibility or strong early inbreeding depression. Importantly, it can lead to impaired female function through ovule or seed discounting when stigmas receive mixtures of self and cross pollen, unless cross pollen is able to reach the ovary ahead of self pollen (‘prepotency’). Self‐sterility associated with ovule penetration by self‐pollen tubes appears to be widespread among the Amaryllidaceae.
- We tested for self‐sterility in three Cyrtanthus species – C. contractus, C. ventricosus and C. mackenii – by means of controlled hand‐pollination experiments. To determine the growth rates and frequency of ovule penetration by self‐ versus cross‐pollen tubes, we used fluorescence microscopy to examine flowers of C. contractus harvested 24, 48 and 72 h after pollination, in conjunction with a novel method of processing these images digitally. To test the potential for ovule discounting (loss of cross‐fertilisation opportunities when ovules are disabled by self‐pollination), we pollinated flowers of C. contractus and C. mackenii with mixtures of self‐ and cross pollen.
- We recorded full self‐sterility for C. contractus and C. ventricosus, and partial self‐sterility for C. mackenii. In C. contractus, we found no differences in the growth rates of self‐ and cross‐pollen tubes, nor in the proportions of ovules penetrated by self‐ and cross‐pollen tubes. In this species, seed set was depressed (relative to cross‐pollinated controls) when flowers received a mixture of self and cross pollen, but this was not the case for C. mackenii.
- These results reveal variation in breeding systems among Cyrtanthus species and highlight the potential for gender conflict in self‐sterile species in which ovules are penetrated and disabled by pollen tubes from self pollen.
20.
Abstract: The breeding system of Luehea grandiflora (Tiliaceae‐Malvaceae s.l.) was investigated using hand pollinations and fluorescence microscopy studies of pollen tube growth. Although selfed flowers persisted for some 10 days, our study indicates that L. grandiflora is self‐incompatible, with self pollen tube inhibition in the upper style, as occurs in many taxa with homomorphic, gametophytic self‐incompatibility (GSI). L. grandiflora is only the second species reported within the Malvales with homomorphic stylar inhibition. This result is discussed within the context of a report for self‐compatibility in this species, and we also consider the phylogenetic implications for the occurrence of GSI in the family Malvaceae s.l. 相似文献