排序方式: 共有92条查询结果,搜索用时 15 毫秒
31.
Bracalello A Santopietro V Vassalli M Marletta G Del Gaudio R Bochicchio B Pepe A 《Biomacromolecules》2011,12(8):2957-2965
Protein-inspired biomaterials have gained great interest as an alternative to synthetic polymers, in particular, for their potential use as biomedical devices. The potential inspiring models are mainly proteins able to confer mechanical properties to tissues and organs, such as elasticity (elastin, resilin, spider silk) and strength (collagen, silk). The proper combination of repetitive sequences, each of them derived from different proteins, represents a useful tool for obtaining biomaterials with tailored mechanical properties and biological functions. In this report we describe the design, the production, and the preliminary characterization of a chimeric polypeptide, based on sequences derived from the highly resilient proteins resilin and elastin and from collagen-like sequences. The results show that the obtained chimeric recombinant material exhibits promising self-assembling properties. Young's modulus of the fibers was determined by AFM image analysis and lies in the range of 0.1-3 MPa in agreement with the expectations for elastin-like and resilin-like materials. 相似文献
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Anna M. Salvi Pasquale Moscarelli Brigida Bochicchio Giuseppe Lanza James E. Castle 《Biopolymers》2013,99(5):292-313
Previous work on elastin‐like polypeptides (ELPs) made of hydrophobic amino acids of the type XxxGlyGlyZzzGly (Xxx, Zzz = Val, Leu) has consistently shown that differing dominant supramolecular structures were formed when the suspending media were varied: helical, amyloid‐like fibers when suspended in water and globules evolving into “string of bead” structures, poly(ValGlyGlyValGly), or cigar‐like bundles, poly(ValGlyGlyLeuGly), when suspended in methyl alcohol. Comparative experiments with poly(LeuGlyGlyValGly) have further indicated that the interface energy plays a significant role and that solvation effects act in concomitance with the intrinsic aggregation propensity of the repeat sequence. Continuing our investigation on ELPs using surface (X‐ray photoelectron spectroscopy, atomic force microscopy) and bulk (circular dichroism, Fourier transform infrared spectroscopy) techniques for their characterization, here we have compared the effect of suspending solvents (H2O, dimethylsulfoxide, ethylene glycol, and MeOH) on poly(ValGlyGlyValGly), the polypeptide most inclined to form long and well‐refined helical fibers in water, searching for the signature of intermolecular interactions occurring between the polypeptide chains in the given suspension. The influence of sequence specificities has been studied by comparing poly(ValGlyGlyValGly) and poly(LeuGlyGlyValGly) with a similar degree of polymerization. Deposits on substrates of the polypeptides were characterized taking into account the differing evaporation rate of solvents, and tests on their stability in ultra high vacuum were performed. Finally, combining experimental and computational studies, we have revaluated the three‐dimensional modeling previously proposed for the supramolecular assembly in water of poly(ValGlyGlyValGly). The results were discussed and rationalized also in the light of published data. © 2012 Wiley Periodicals, Inc. Biopolymers 99: 292–292, 2013. 相似文献
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Ostuni A Bochicchio B Armentano MF Bisaccia F Tamburro AM 《Biophysical journal》2007,93(10):3640-3651
One of the unusual properties of elastin is its ability to coacervate, which has been proposed to play an important role in the alignment of monomeric elastin for cross-linking into the polymeric elastin matrix. The temperature at which this transition takes place depends on several factors including protein concentration, ionic strength, and pH. Previously, polypeptide sequences encoded by different exons of the human tropoelastin gene have been analyzed for their ability to coacervate and to self-assemble. Few of them were indeed able to coacervate and only one, that encoded by exon 30 (EX30), gave amyloid fibers. In this article, we report on two chemically synthesized peptides-a decapeptide and an octadecapeptide-whose sequences are contained in the longer EX30 peptide and on a polypeptide (EX1-7) of 125 amino-acid residues corresponding to the sequence coded by the exons 1-7 and on a polypeptide (EX2-7) of 99 amino-acid residues encoded by exons 2-7 of human tropoelastin obtained by recombinant DNA techniques. Molecular and supramolecular structural characterization of these peptides showed that a minimum sequence of approximately 20 amino acids is needed to form amyloid fibers in the exon 30-derived peptides. The N-terminal region of mature tropoelastin (EX2-7) gives rise to a coacervate and forms elastinlike fibers, whereas the polypeptide sequence containing the signal peptide (EX1-7) forms mainly amyloid fibers. Circular dichroism spectra show that beta-structure is ubiquitous in all the sequences studied, suggesting that the presence of a beta-structure is a necessary, although not sufficient, requirement for the appearance of amyloid fibers. 相似文献
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Graziani Vittoria Scognamiglio Monica Esposito Assunta Fiorentino Antonio D’Abrosca Brigida 《Phytochemistry Reviews》2019,18(4):1133-1166
Phytochemistry Reviews - Astragalus is a cosmopolitan genus characterised by a large number of species with an exceptional rate of diversification. Many of these species are used since ancient... 相似文献
35.
Lindfors HE de Koning PE Drijfhout JW Venezia B Ubbink M 《Journal of biomolecular NMR》2008,41(3):157-167
Paramagnetic relaxation enhancement provides a tool for studying the dynamics as well as the structure of macromolecular complexes. The application of side-chain coupled spin-labels is limited by the mobility of the free radical. The cyclic, rigid amino acid spin-label TOAC (2,2,6,6-Tetramethylpiperidine-1-oxyl-4-amino-4-carboxylic acid), which can be incorporated straightforwardly by peptide synthesis, provides an attractive alternative. In this study, TOAC was incorporated into a peptide derived from focal adhesion kinase (FAK), and the interaction of the peptide with the Src homology 3 (SH3) domain of Src kinase was studied, using paramagnetic NMR. Placing TOAC within the binding motif of the peptide has a considerable effect on the peptide-protein binding, lowering the affinity substantially. When the TOAC is positioned just outside the binding motif, the binding constant remains nearly unaffected. Although the SH3 domain binds weakly and transiently to proline-rich peptides from FAK, the interaction is not very dynamic and the relative position of the spin-label to the protein is well-defined. It is concluded that TOAC can be used to generate reliable paramagnetic NMR restraints. 相似文献
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Massimo Aureli Rosaria Bassi Alessandro Prinetti Elena Chiricozzi Brigida Pappalardi Vanna Chigorno Nadia Di Muzio Nicoletta Loberto Sandro Sonnino 《Glycoconjugate journal》2012,29(8-9):585-597
We detected significant levels of β-glucosidase, β-galactosidase, sialidase Neu3 and sphingomyelinase activities associated with the plasma membrane of fibroblasts from normal and Niemann-Pick subjects and of cells from breast, ovary, colon and neuroblastoma tumors in culture. All of the cells subjected to ionizing radiations showed an increase of the activity of plasma membrane β-glucosidase, β-galactosidase and sialidase Neu3, in addition of the well known increase of activity of plasma membrane sphingomyelinase, under similar conditions. Human breast cancer cell line T47D was studied in detail. In these cells the increase of activity of β-glucosidase and β-galactosidase was parallel to the increase of irradiation dose up to 60?Gy and continued with time, at least up to 72?h from irradiation. β-glucosidase increased up to 17 times and β-galactosidase up to 40 times with respect to control. Sialidase Neu3 and sphingomyelinase increased about 2 times at a dose of 20?Gy but no further significant differences were observed with increase of radiation dose and time. After irradiation, we observed a reduction of cell proliferation, an increase of apoptotic cell death and an increase of plasma membrane ceramide up to 3 times, with respect to control cells. Tritiated GM3 ganglioside has been administered to T47D cells under conditions that prevented the lysosomal catabolism. GM3 became component of the plasma membranes and was transformed into LacCer, GlcCer and ceramide. The quantity of ceramide produced in irradiated cells was about two times that of control cells. 相似文献
37.
Kouadio Ibrahime Sinan Gokhan Zengin Antonio Fiorentino Brigida D'Abrosca Gunes Ak Devina Lobine Ouattara Katinan Etienne Anwar Hussein Subratty Mohamad Fawzi Mahomoodally 《化学与生物多样性》2021,18(10):e2100371
Spermacoce verticillata (L.) G. Mey. is commonly used in the folk medicine by various cultures to manage common diseases. Herein, the chemical and biological profiles of S. verticillata were studied in order to provide a comprehensive characterization of bioactive compounds and also to highlight the therapeutic properties. The in vitro antioxidant activity using free-radical scavenging, phosphomolybdenum, ferrous-ion chelating and reducing power assays, and the inhibitory activity against key enzymes such as acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), tyrosinase, α-amylase and α-glucosidase of S. verticillata extracts (dichloromethane, ethyl acetate, methanol and water) were investigated. The highest total phenolic and flavonoid content were observed in the methanolic and aqueous extracts. Exhaustive 2DNMR investigation has revealed the presence of rutin, ursolic and oleanoic acids. The methanolic extract, followed by aqueous extract have showed remarkable free radical quenching and reducing ability, while the dichloromethane extract was the best source of metal chelators. The tested extracts showed notable inhibitory activity against cholinesterases (AChE: 1.63–4.99 mg GALAE/g extract and BChE: 12.40–15.48 mg GALAE/g extract) and tyrosinase (60.85–159.64 mg KAE/g extract). No inhibitory activity was displayed by ethyl acetate and aqueous extracts against BChE and tyrosinase, respectively. All the tested extracts showed modest α-amylase inhibitory activity, while only the ethyl acetate and aqueous extracts were potent against α-glycosidase. This study further validates the use of S. verticillata in the traditional medicine, while advocating for further investigation for phytomedicine development. 相似文献
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Busato AP Vargas-Rechia CG Gorin PA Petkowicz CL Tischer CA Bochicchio R Reicher F 《International journal of biological macromolecules》2005,35(5):277-282
A homogeneous fucogalactoxyloglucan, isolated from the leaves of Hymenaea courbaril, was analysed by methylation-GC–MS. These procedures involved derived partially O-methylated alditol acetates and acetylated aldononitriles, which demonstrated the presence of both 2-O- and 4-O-substituted Xylp units in the side-chains. The presence of the unusual, latter structure was confirmed by 2D NMR spectroscopy with a correlated HMQC C-4/H-4 signal at δ 77.8/3.73. A similar 4-O-substituted xylosyl structure was present in a decasaccharide Glc4Xyl3Gal2Fuc obtained via endo-glucanase treatment of the polysaccharide, which gave rise to a molecular ion with m/z 1555 (ESI-MS, Na+ form). 相似文献