- A dual-detection strategy in the chromatographic analysis of 2-aminoacridone-derivatized oligosaccharides
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A protocol has been developed involving the derivatization of glycan mixtures with 2-aminoacridone and co-injection with a dextran ladder derivatized with methyl 4-aminobenzoate (M-4AB). These two derivatizing agents have very different ultraviolet absorbance and fluorescence characteristics. A Chromatographic separation using a normal-phase column support followed by in-series UV and fluorescence detection allowed simultaneous analysis of the two mixtures of the separately derivatized carbohydrates without any interference. This new approach uses the M-4AB dextran ladder derivatives as internal standards spanning the whole chromatogram, allowing an accurate and detailed comparison of glycosylation profiles. It also saves much time by avoiding the necessity of "sandwiching" an unknown glycan mixture between two Chromatographic runs of a dextran ladder. The use of this technique has been demonstrated in the case of glycans released from ribonuclease B and human IgG.
- Birrell, Helen,Charlwood, Joanne,Lynch, Ian,North, Simon,Camilleri, Patrick
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- A New Potent Inhibitor of Glycogen Phosphorylase Reveals the Basicity of the Catalytic Site
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The design and synthesis of a glucose-based acridone derivative (GLAC), a potent inhibitor of glycogen phosphorylase (GP) are described. GLAC is the first inhibitor of glycogen phosphorylase, the electronic absorption properties of which are clearly distinguishable from those of the enzyme. This allows probing subtle interactions in the catalytic site. The GLAC absorption spectra, associated with X-ray crystallography and quantum chemistry calculations, reveal that part of the catalytic site of GP behaves as a highly basic environment in which GLAC exists as a bis-anion. This is explained by water-bridged hydrogen-bonding interactions with specific catalytic site residues.
- Mamais, Michael,Degli Esposti, Alessandra,Kouloumoundra, Virginia,Gustavsson, Thomas,Monti, Filippo,Venturini, Alessandro,Chrysina, Evangelia D.,Markovitsi, Dimitra,Gimisis, Thanasis
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- Improving the fluorescent probe acridonylalanine through a combination of theory and experiment
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Acridonylalanine (Acd) is a useful fluorophore for studying proteins by fluorescence spectroscopy, but it can potentially be improved by being made longer wavelength or brighter. Here, we report the synthesis of Acd core derivatives and their photophysical characterization. We also performed ab initio calculations of the absorption and emission spectra of Acd derivatives, which agree well with experimental measurements. The amino acid aminoacridonylalanine (Aad) was synthesized in forms appropriate for genetic incorporation and peptide synthesis. We show that Aad is a superior F?rster resonance energy transfer acceptor to Acd in a peptide cleavage assay and that Aad can be activated by an aminoacyl tRNA synthetase for genetic incorporation. Together, these results show that we can use computation to design enhanced Acd derivatives, which can be used in peptides and proteins.
- Sungwienwong, Itthipol,Ferrie, John J.,Jun, Joomyung V.,Liu, Chunxiao,Barrett, Taylor M.,Hostetler, Zachary M.,Ieda, Naoya,Hendricks, Amara,Muthusamy, Anand K.,Kohli, Rahul M.,Chenoweth, David M.,Petersson, George A.,Petersson, E. James
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- New sulphonamides with acridinic nucleus
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Twelve new sulphonamides with acridonic and acridinic nucleus were synthesized, in which the sulphonamidic group appears in positions 1, 2, 3 and 4. We also obtained the corresponding acridanes, but we did not isolate them. We proved that in the case of 2-nitroacridone synthesis, by ring closure of 4-nitrodiphenylamine-2-carboxylic acid, working in the presence of sulphuric acid, sulphonation takes place. To reduce some nitroacridones we used hydrazine hydrate in the presence of Ni from formiate and Ni Raney, a method not yet mentioned in the literature for compounds of this class, and which presents many advantages. We proved that sulphonamides with acridonic nucleus can be transformed into the corresponding acridines, by reduction with Na-amalgam. The studied new substances show a noteworthy activity against microorganisms.
- Ferencz, László,Fǎrcǎ?an, Valer,Silberg, Ioan A.
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p. 801 - 811
(2007/10/03)
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- Structure-trypanodical activity relationships
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A set of 9-thioalkylacridinones, has been prepared and investigated' in vitro' against T. cruzi. Structure-antiparasitic activity relationships are detailed with a view to identify the major structural parameters for the activity under consideration.
- Bsiri,Johnson,Kayirere,Galy,Galy,Barbe,Osuna,Mesa-Valle,Castilla Calvente,Rodriguez-Cabezas
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