- Identification and Characterization of a Single High-Affinity Fatty Acid Binding Site in Human Serum Albumin
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A single high-affinity fatty acid binding site in the important human transport protein serum albumin (HSA) is identified and characterized using an NBD (7-nitrobenz-2-oxa-1,3-diazol-4-yl)-C12 fatty acid. This ligand exhibits a 1:1 binding stoichiometry in its HSA complex with high site-specificity. The complex dissociation constant is determined by titration experiments as well as radioactive equilibrium dialysis. Competition experiments with the known HSA-binding drugs warfarin and ibuprofen confirm the new binding site to be different from Sudlow-sites I and II. These binding studies are extended to other albumin binders and fatty acid derivatives. Furthermore an X-ray crystal structure allows locating the binding site in HSA subdomain IIA. The knowledge about this novel HSA site will be important for drug depot development and for understanding drug-protein interaction, which are important prerequisites for modulation of drug pharmacokinetics.
- Wenskowsky, Lea,Schreuder, Herman,Derdau, Volker,Matter, Hans,Volkmar, Julia,Nazaré, Marc,Opatz, Till,Petry, Stefan
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supporting information
p. 1044 - 1048
(2018/01/01)
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- Shining new light on ancient drugs: preparation and subcellular localisation of novel fluorescent analogues of Cinchona alkaloids in intraerythrocytic Plasmodium falciparum
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Fluorescent derivatives of the archetypal antimalarial quinine and its diastereomer, quinidine, suitable for cellular imaging have been synthesised by attaching the small extrinsic fluorophore, NBD. Interactions of these derivatives with ferriprotoporphyrin IX were evaluated to verify that insights generated by live-cell imaging were relevant to the parent molecules. These analogues are shown by confocal and super-resolution microscopy to accumulate selectively in Plasmodium falciparum. Localisation to the region corresponding to the digestive vacuole supports the putative primary role of these alkaloids as haemozoin inhibitors. Quantitative analysis revealed minimal accumulation within the nucleus, rejecting the disruption of DNA replication as a possible mode of action. While extensive localisation to phospholipid structures and associated organelles was observed, the analogues did not show evidence of association with neutral lipid bodies.
- Woodland, John G.,Hunter, Roger,Smith, Peter J.,Egan, Timothy J.
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supporting information
p. 589 - 597
(2017/01/25)
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- Design and synthesis of fluorescence-labeled closo-dodecaborate lipid: Its liposome formation and in vivo imaging targeting of tumors for boron neutron capture therapy
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The fluorescence-labeled closo-dodecaborane lipid (FL-SBL) was synthesized from (S)-(+)-1,2-isopropylideneglycerol as a chiral starting material. FL-SBL was readily accumulated into the PEGylated DSPC liposomes prepared from DSPC, CH, and DSPE-PEG-OMe by the post insertion protocol. The boron concentrations and the fluorescent intensities of the FL-SBL-labeled DSPC liposomes increased with the increase of the additive FL-SBL, and the maximum emission wavelength of the liposomes appeared at 531 nm. A preliminary in vivo imaging study of tumor-bearing mice revealed that the FL-SBL-labeled DSPC liposomes were delivered to the tumor tissue but not distributed to hypoxic regions.
- Nakamura, Hiroyuki,Ueda, Noriko,Ban, Hyun Seung,Ueno, Manabu,Tachikawa, Shoji
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experimental part
p. 1374 - 1380
(2012/04/10)
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- Novel fluorescent ceramide derivatives for probing ceramidase substrate specificity
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Ceramidases are key regulators of cell fate. The biochemistry of different ceramidases and of their substrate ceramide appears to be complex, mainly due to specific biophysical characteristics at the water-membrane interface. In the present study, we describe the design and synthesis of a set of fluorescently labeled ceramides as substrates for acid and neutral ceramidases. For the first time we have replaced the commonly used polar NBD-dye with the lipophilic Nile Red (NR) dye. Analysis of kinetic data reveal that although both the dyes do not have any noticeable preference for the substitution at acyl or sphingosine (Sph) part in ceramide towards hydrolysis by acid ceramidase, the ceramides with acyl-substituted NBD and Sph-substituted NR dyes have been found to be a better substrate for neutral ceramidase.
- Bhabak, Krishna P.,Proksch, Denny,Redmer, Susanne,Arenz, Christoph
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p. 6154 - 6161
(2012/11/07)
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- Synthesis of fluorescent C24-ceramide: Evidence for acyl chain length dependent differences in penetration of exogenous NBD-ceramides into human skin
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Topical skin lipid supplementation may provide opportunities for controlling ceramide (Cer) deficiency in skin diseases such as atopic dermatitis or psoriasis. Here we describe the synthesis of a long-chain 7-nitrobenzo[c][1,2,5]oxadiazol-4-yl (NBD)-labeled Cer and its different penetration through human skin compared to widely used short-chain fluorescent Cer tools.
- Novotny, Jakub,Pospěchová, Kate?ina,Hrabálek, Alexandr,?áp, Robert,Vávrová, Kate?ina
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supporting information; experimental part
p. 6975 - 6977
(2010/06/16)
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- Visualization of sialyl LewisX glycosphingolipid microdomains in model membranes as selectin recognition motifs using a fluorescence label
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Selectin-induced leukocyte rolling along the endothelial surface is an essential step in the cellular immune response. For efficient recognition, the relevant carbohydrate epitope sialyl LewisX (sLeX; α-Neup5Ac-(2→3)-β-Galp-(1→4)-[α-Fucp-(1→3)]GlcpNAc) has to be arranged in clusters. We describe the synthesis of the sLeX-glycosphingolipid (sLeX-GSL) with a NBD fluorescence label in the tail region, which allows the direct visualization of sLeX-GSL microdomains to very low concentrations (0.01 mol %) in various planar phosphocholine matrices by fluorescence microscopy. Cell rolling experiments of E-selectin expressing cells along these membranes confirmed that the fluorescence analog behaves similar to the naturally occuring sLeX-GSL. This is direct evidence for recent hypotheses on multivalent sLeX binding as molecular basis for selectin-mediated cell rolling.
- Gege, Christian,Schumacher, Gabriele,Rothe, Ulrich,Schmidt, Richard R.,Bendas, Gerd
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p. 2361 - 2368
(2008/12/21)
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