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The adsorption and immobilisation of human insulin onto the bio-compatible nanosheets including graphene monoxide, silicon carbide and boron nitride nanosheets were studied by molecular dynamics simulation at the temperature of 310 K. After equilibration, heating and 100 ns production molecular dynamic runs, it was found that the insulin was adsorbed and immobilised onto the considered surfaces in a native folded state. The structural parameters, including root-mean-square deviation and fluctuation, surface accessible solvent area, radius of gyration (Rg) and the distance between the centre of the mass of immobilised protein and the surface of the considered nanosheets, were measured, analysed and discussed. The energetics of the studied systems such as the interaction energy between protein and nanosheet was also measured and addressed. The discussions were centred on the structural and energetic parameters of the protein and nanosheets, including charge density, hydrophobicity, hydrophilicity and residue polarity. The results also showed that the active site of C-termini of chain B played an important role in the adsorption process and this could be helpful in the protection of insulin in its smart delivery and release applications. 相似文献
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Cartoni C Schininà ME Maras B Nonno R Vaccari G Di Bari M Conte M De Pascalis A Principe S Cardone F Pocchiari M Agrimi U 《Journal of chromatography. B, Analytical technologies in the biomedical and life sciences》2007,849(1-2):302-306
The conversion of the cellular prion protein (PrP(C)) into a misfolded isoform (PrP(TSE)) that accumulates in the brain of affected individuals is the key feature of transmissible spongiform encephalopaties (TSEs). Susceptibility to TSEs is influenced by polymorphisms of the prion gene suggesting that the presence of certain amino acid residues may facilitate the pathological conversion. In this work, we describe a quantitative, fast and reliable HPLC-MS method that allowed to demonstrate that in the brain of 109(Met/Ile) heterozygous bank voles infected with the mouse adapted scrapie strain 139A, there are comparable amounts of PrP(TSE) with methionine or isoleucine in position 109, suggesting that in this TSE model the two allotypes have similar rates of accumulation. This method can be easily adapted for the quantitative determination of PrP allotypes in the brain of other natural or experimental TSE models. 相似文献
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Structure of Pyridoxal Kinase from Sheep Brain and Role of the Tryptophanyl Residues 总被引:3,自引:0,他引:3
Bruno Maras Sofia Valiante Stefania Orru Maurizio Simmaco Donatella Barra Jorge E. Churchich 《Journal of Protein Chemistry》1999,18(3):259-268
The primary structure of sheep brain pyridoxal kinase has been determined by direct chemical and physical methods. The enzyme contains 312 amino acid residues with an acetylated methionine at the N-terminus, yielding a molecular mass of 34,861 Da. The functional role played by the two tryptophanyl residues in positions 52 and 244 of the polypeptide chain has been investigated by fluorescence spectroscopy. The tryptophanyl residues are not completely exposed to the rapidly relaxing solvent and they are poorly accessible to collisional quenchers. Chemical modification with NBS abolishes the catalytic activity of the kinase. The amino acid sequence of the sheep brain enzyme shows high similarity (86.2% identity) with the human pyridoxal kinase recently reported [Hanna, Turner, and Kirkness, (1997), J. Biol. Chem.
272, 10756–10760]. Comparison of the mammalian proteins with bacterial and yeast putative pyridoxal kinases retrieved from the Swiss-Prot data bank shows a low degree of overall similarity. In particular, the putative ATP-binding domain is conserved, whereas the region that appears to be crucial in the binding of the pyridoxal substrate is not. Thus, the assignment of the bacterial and yeast cDNA-deduced proteins as pyridoxal kinases should be taken with caution. 相似文献
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Munevver Meltem Yige 《Arts Education Policy Review》2019,120(1):11-18
This article examines the history of art education in Turkey. Since the beginning, the purposes of the arts and art education have been a point of discussion by various authorities. Whether art education should be taught, and how it needs to be taught, have been at the forefront of educationalists' minds. As a result, introducing certain models of art education has been a challenge. The objective of this article is to present the changes in art education since the 19th century in Turkey. The main focus is on art education practices and policies and an overview of key events in Turkey's history of art education. The article also presents issues related to the importance of visual arts education in Turkish primary school settings. In so doing, this research aims to show readers how past developments helped to create the current visual art education policy in Turkey. 相似文献
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Ozipek M Saracoglu I Ogihara Y Caliş I 《Zeitschrift für Naturforschung. C, Journal of biosciences》2002,57(7-8):603-608
A new nuatigenin-type steroidal saponin, multifidoside (2), was isolated from the aerial parts of Veronica fuhsii and V multifida and its structure was identified as 3-O-([alpha-L-rhamnopyranosyl-(1-->2glu)]-[beta-D-glucopyranosyl-(1-->4rha)-alpha-L-rhamnopyranosyl (1-->4glu)]-beta-D-glucopyranosyl]nuatigenin 26-O-beta-D-glucopyranoside. Additionally, a known steroidal saponoside, aculeatiside A (1), from V. fuhsii, a phenylethanoid glycoside, verpectoside A (3), and a flavon glycoside, isoscutellarein 7-O-(2"-O-6"-O-acetyl-beta-D-allopyranosyl-beta-D-glucopyranoside) (4) from V. multifida were isolated. 相似文献
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This paper presents a simple method of carrying deeply located recipient vascular structures to the surface in order to facilitate end-to-side anastomoses in free-flap transplantations. 相似文献