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101.
Maksimoska J Williams DS Atilla-Gokcumen GE Smalley KS Carroll PJ Webster RD Filippakopoulos P Knapp S Herlyn M Meggers E 《Chemistry (Weinheim an der Bergstrasse, Germany)》2008,14(16):4816-4822
In this study, we probe and verify the concept of designing unreactive bioactive metal complexes, in which the metal possesses a purely structural function, by investigating the consequences of replacing ruthenium in a bioactive half-sandwich kinase inhibitor scaffold by its heavier congener osmium. The two isostructural complexes are compared with respect to their anticancer properties in 1205 Lu melanoma cells, activation of the Wnt signaling pathway, IC(50) values against the protein kinases GSK-3beta and Pim-1, and binding modes to the protein kinase Pim-1 by protein crystallography. It was found that the two congeners display almost indistinguishable biological activities, which can be explained by their nearly identical three-dimensional structures and their identical mode of action as protein kinase inhibitors. This is a unique example in which the replacement of a metal in an anticancer scaffold by its heavier homologue does not alter its biological activity. 相似文献
102.
Dynamic Fourier Transform Infra-Red (FT-IR) spectroscopy was used to examine the interactions among cellulose, xyloglucan,
pectin, protein and lignin in the outer fibre wall layers of spruce wood tracheids. Knowledge regarding these interactions
is fundamental for understanding the fibre separation in a mechanical pulping process. Sheets made from an enriched primary
cell wall material were used for studying the viscoelastic response of the polymers. The results indicated that strong interactions
exist among lignin, protein, pectin, xyloglucan and cellulose in the primary cell wall. This signified a closely linked network
structure of the components on the fibre surface. This ultrastructural arrangement in the primary cell wall and the relatively
high content of lignin, pectin and protein in it, means that the primary cell wall is more submissive to selective chemical
attacks, when compared to the secondary cell wall. A low ratio of cellulose Iα to cellulose Iβ in the primary cell wall was
also found. 相似文献
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Petra Hoffmann Marcel Hülsewig Sevim Duvar Holger Ziehr Michael Mormann Jasna Peter‐Katalinić Alexander W. Friedrich Helge Karch Johannes Müthing 《Rapid communications in mass spectrometry : RCM》2010,24(15):2295-2304
Shiga toxin (Stx, synonymous to verotoxin, VT) binds with high and low affinity to the globo‐series neutral glycosphingolipids (GSLs), globotriaosylceramide (Gb3Cer or Galα4Galβ4Glcβ1Cer, also known as CD77) and globotetraosylceramide (Gb4Cer or GalNAcβ3Galα4Galβ4Glcβ1Cer), respectively, which represent the targets of Stxs on many different cell types. B‐cell‐derived Raji cells and THP‐1 cells of monocytic origin are widely used for the investigation of Stx‐mediated cellular response, because Stx is known to cause cell death in both cell lines. Despite their functional importance, the Stx receptors of Raji and THP‐1 cells have so far not been investigated. This prompted us to explore the structures of their GSL receptors in detail by means of nanoelectrospray ionization quadrupole time‐of‐flight mass spectrometry (nanoESI‐QTOF‐MS) with collision‐induced dissociation (CID) in conjunction with Stx1 as well as anti‐Gb3Cer and anti‐Gb4Cer antibodies. Using the combination of a thin‐layer chromatography (TLC) overlay assay and MS1 and MS2 analysis we identified Gb3Cer (d18:1, C24:1/C24:0) as the prevalent Stx1‐receptor accompanied by less abundant Gb3Cer (d18:1, C16:0) in the neutral GSL fraction of Raji cells. The same Gb3Cer species but with almost equal proportions of the C24:1/C24:0 and C16:0 variants were found in THP‐1 cells. In addition, unusual hydroxylated Gb3Cer (d18:1, C24:1/C24:0) and Gb3Cer (d18:1, C26:1) could be identified in trace quantities in both cell lines. As the most obvious difference between Raji and THP‐1 cells we observed the expression of Gb4Cer in THP‐1 cells, whereas Raji cells failed to express this elongation product of Gb3Cer. Both short‐ and long‐chain fatty acid carrying Gb4Cer (d18:1, C16:0) and Gb4Cer (d18:1, C24:1/C24:0), respectively, were the prevalent Gb4Cer variants. This first report on the differential expression of Gb3Cer and Gb4Cer and their structural diversity in lymphoid and myeloid cell lines supports the hypothesis that such heterogeneities might play a functional role in the molecular assembly of GSLs in membrane organization and cellular signaling of Stx‐susceptible cells. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
106.
We use a test particle simulation model based on gyro-averaged equations of motion to study the influence of oblique magnetospherically reflected (MR) whistlers on the near-loss-cone distribution function of radiation belt electrons. We find that MR whistlers originating in lightning can resonantly interact with radiation belt electrons over a broad range of L-shells and precipitate higher energy electrons from lower L-shells. Electrons in the energy range of 1–2.6 MeV are precipitated from L=2, whereas from L=4 the precipitated electron energy range is 150–220 keV. The precipitated differential electron flux due to this interaction is higher for higher L-shells, and the maximum value ranges from
at
at L=4. The lifetimes of radiation belt electrons in a given magnetic flux tube around the L-shell on which the interaction takes place are found to be of the order of several days, comparable to lifetimes corresponding to electron loss induced by hiss, which was heretofore assumed to be the dominant loss mechanism [1]. The minimum electron lifetimes vary from 2.47 days for E=1.11 MeV electrons at L=2 to 4.64 days for E=173 keV electrons at L=4.LOLA Research Center, Belgrade, Yugoslavia. STAR Laboratory, Stanford University, Stanford, California. Published in Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 37, No. 6, pp. 727–740, June, 1994. 相似文献
107.
Marina Krvavica Dario Lasi Jasenka Gajdo Kljusuri Jelena ugum piro Janovi Sran Milovac Jasna Bonir 《Molecules (Basel, Switzerland)》2021,26(14)
Chemical characteristics of raw and processed Istarski pršut (PDO) produced from two different pig genotypes were studied with special emphasis on amino and fatty acid composition and factors of lipid stability. Raw hams of Large White (LW)xLandrace (L), and (LWxL)xDuroc (D) pig genotypes were used in the study (20 hams of each genotype). All left raw hams from each carcass were processed in accordance with the PDO specification of Istarski pršut, and other half (the right ones) of LWxL)xD genotype were used for analyses of raw hams (fresh muscles). Istarski pršut was evaluated on the basis of the chemical parameters of the raw and matured lean ham. The process of dry curing significantly influenced the chemical properties of Istarski pršut. Despite the higher content of intramuscular fat and polyunsaturated fatty acids, the fat of (LWxL)xD ham was much more resistant to hydrolysis and oxidation, suggesting that fatty acid profile and other factors, also play a significant role. Significant differences between pig genotypes in the amino acid and fatty acid profiles were found. The analyzed Istarski pršut may be distinguished by prints of multivariate chemometric statistical analysis, based on their amino acid and fatty acid compositions. 相似文献
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109.
Laura Bindila Reinaldo Almeida Alistair Sterling Mark Allen Jasna Peter-Katalinić Alina Zamfir 《Journal of mass spectrometry : JMS》2004,39(10):1190-1201
Implementation and optimization of an off-line capillary electrophoresis (CE)/(−)nanoESIchip-quadrupole time-of-flight (QTOF) mass spectrometric (MS) and tandem MS system for compositional mapping and structural investigation of components in complex carbohydrate mixtures is described. The approach was developed for glycoscreening and applied to O-glycosylated peptides from urine of a patient suffering from α-N-acetylhexosaminidase deficiency, known as Schindler's disease. The fundamental issue of sensitivity, previously representing a serious drawback of the off-line CE/MS analysis, could be positively addressed by the off-line conjunction of CE with automated chip-based ESI-QTOF-MS to provide flexibility for CE/chip MS coupling and enhance structural elucidation of single components in heterogeneous mixtures. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
110.
Identification and structural characterization of novel O‐ and N‐glycoforms in the urine of a Schindler disease patient by Orbitrap mass spectrometry 下载免费PDF全文
Mirela Sarbu Cristian V. A. Munteanu Liana Dehelean Andrei J. Petrescu Jasna Peter‐Katalinic Alina D. Zamfir 《Journal of mass spectrometry : JMS》2015,50(9):1044-1056
Schindler disease is an inherited metabolic disorder caused by the deficient activity of α‐N‐acetylgalactosaminidase enzyme. An accurate diagnosis requires, besides clinical examination, complex and costly biochemical and molecular genetic tests. In the last years, mass spectrometry (MS) based on nanofluidics and high‐resolution instruments has become a successful alternative for disease diagnosis based on the investigation of O‐glycopeptides in patient urine. A complex mixture of glycoforms extracted from the urine of a 3‐year‐old patient was investigated by Orbitrap MS equipped with Nanospray Flex Ion Source in the negative ion mode. For structural characterization of several molecular species, collision‐induced dissociation MS2–MS3 was carried out using collision energy values within 20–60 eV range. By our approach, 39 novel species associated to this condition were identified, among which O‐glycopeptides, free O‐glycans and one structure corresponding to an N‐glycan never characterized in the context of Schindler disease. The experiments conducted at a resolution of 60 000 allowed the discrimination and identification of a total number of 69 different species with an average mass accuracy of 9.87 ppm, an in‐run reproducibility of almost 100%, an experiment‐to‐experiment and day‐to‐day reproducibility of about 95%. This study brings contributions in the diagnosis of Schindler disease through the elucidation of potential biomarker species in urine. Our multistage MS results completed with 39 new glycoforms the inventory of potential biomarker structures associated to Schindler disease. For the first time, an N‐glycan was identified and structurally characterized in Schindler patient urine, which opens new research directions in the field. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献