- Visible detection of biotin by thin-film interference: Thickness control through exchange reaction of biotin/dethiobiotin-avidin bonding
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This work presents a unique method for the visible detection of site-specific molecular interactions between proteins and small molecules. In this method, a silica thin-film, which shows thin-film interference, was used as a substrate. On its surface, protein multilayers made up of avidin- and dethiobiotin-labeled bovine serum albumin (BSA) were constructed via the avidin-dethiobiotin bond. Film construction behaviors were confirmed visibly owing to the uniform change of the interference color. This multilayer was able to disassemble by biotin addition, taking advantage of the higher association constant of avidin-biotin bonding. Disassembling of the multilayer was also confirmable as a drastic color change seen by the naked eye. The Royal Society of Chemistry.
- Tominaga, Ryojiro,Sivakumar, Muthusamy,Tanaka, Masayoshi,Kinoshita, Takatoshi
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- Cell-Penetrating Streptavidin: A General Tool for Bifunctional Delivery with Spatiotemporal Control, Mediated by Transport Systems Such as Adaptive Benzopolysulfane Networks
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In this report, cell-penetrating streptavidin (CPS) is introduced to exploit the full power of streptavidin-biotin biotechnology in cellular uptake. For this purpose, transporters, here cyclic oligochalcogenides (COCs), are covalently attached to lysines of wild-type streptavidin. This leaves all four biotin binding sites free for at least bifunctional delivery. To maximize the standards of the quantitative evaluation of cytosolic delivery, the recent chloroalkane penetration assay (CAPA) is coupled with automated high content (HC) imaging, a technique that combines the advantages of fluorescence microscopy and flow cytometry. According to the resulting HC-CAPA, cytosolic delivery of CPS equipped with four benzopolysulfanes was the best among all tested CPSs, also better than the much smaller TAT peptide, the original cell-penetrating peptide from HIV. HaloTag-GFP fusion proteins expressed on mitochondria were successfully targeted using CPS carrying two different biotinylated ligands, HaloTag substrates or anti-GFP nanobodies, interfaced with peptide nucleic acids, flipper force probes, or fluorescent substrates. The delivered substrates could be released from CPS into the cytosol through desthiobiotin-biotin exchange. These results validate CPS as a general tool which enables unrestricted use of streptavidin-biotin biotechnology in cellular uptake.
- Cheng, Yangyang,Derivery, Emmanuel,González-Gaitán, Marcos,López-Andarias, Javier,Laurent, Quentin,Matile, Stefan,Moreau, Dimitri,Saarbach, Jacques,Sakai, Naomi,Winssinger, Nicolas
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- COMPACT HYDROXAMATE-BASED AFFINITY TAGS FOR ARTIFICIALLY TAGGING BIOLOGICAL MACROMOLECULES
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Methods for purifying biological macromolecules are provided. Aspects of the subject methods include contacting the biological macromolecule with an exemplary hydroxamate affinity tag to produce a tagged moiety followed by purification of the tagged moiety by immobilized metal affinity chromatography (IMAC). Also provided are kits comprising an exemplary subject hydroxamate affinity tag, an IMAC resin and a metal ion configured for loading onto the resin, wherein the metal ion is capable of binding to a compound containing the hydroxamate affinity tag.
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- POLYCYCLIC EPOXIDES AND COMPOSITIONS THEREOF WITH ANTI-CANCER ACTIVITIES
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The present technology provides polycyclic epoxides of Formula I, compositions comprising such expoxides and methods of using such epoxides. In particular, these compounds are useful for inhibiting cancer cell proliferation and tumor angiogenesis or treating ovarian, breast, prostate, liver, pancreatic, and colon cancers, as well as leukemia.
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Paragraph 0328-0331
(2016/12/01)
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