- Phototriggered Dynamic and Biomimetic Growth of Chlorosomal Self-Aggregates
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Supramolecular polymerizations mimicking native systems, which are step-by-step constructions to form self-aggregates, were recently developed. However, a general system to successively and spontaneously form self-aggregates from monomeric species remains
- Matsubara, Shogo,Tamiaki, Hitoshi
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- 2-((3,5-Dinitrobenzyl)thio)quinazolinones: Potent Antimycobacterial Agents Activated by Deazaflavin (F420)-Dependent Nitroreductase (Ddn)
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Swapping the substituents in positions 2 and 4 of the previously synthesized but yet undisclosed 5-cyano-4-(methylthio)-2-arylpyrimidin-6-ones 4, ring closure, and further optimization led to the identification of the potent antitubercular 2-thio-substituted quinazolinone 26. Structure-activity relationship (SAR) studies indicated a crucial role for both meta-nitro substituents for antitubercular activity, while the introduction of polar substituents on the quinazolinone core allowed reduction of bovine serum albumin (BSA) binding (63c, 63d). While most of the tested quinazolinones exhibited no cytotoxicity against MRC-5, the most potent compound 26 was found to be mutagenic via the Ames test. This analogue exhibited moderate inhibitory potency against Mycobacterium tuberculosis thymidylate kinase, the target of the 3-cyanopyridones that lies at the basis of the current analogues, indicating that the whole-cell antimycobacterial activity of the present S-substituted thioquinazolinones is likely due to modulation of alternative or additional targets. Diminished antimycobacterial activity was observed against mutants affected in cofactor F420 biosynthesis (fbiC), cofactor reduction (fgd), or deazaflavin-dependent nitroreductase activity (rv3547), indicating that reductive activation of the 3,5-dinitrobenzyl analogues is key to antimycobacterial activity.
- Jian, Yanlin,Forbes, He Eun,Hulpia, Fabian,Risseeuw, Martijn D. P.,Caljon, Guy,Munier-Lehmann, Hélène,Boshoff, Helena I. M.,Van Calenbergh, Serge
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p. 440 - 457
(2021/01/14)
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- Highly activatable and environment-insensitive optical highlighters for selective spatiotemporal imaging of target proteins
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Optical highlighters are photoactivatable fluorescent molecules that exhibit pronounced changes in their spectral properties in response to irradiation with light of a specific wavelength and intensity. Here, we present a novel design strategy for a new class of caged BODIPY (4,4-difluoro-4-bora-3a, 4a-diaza-s-indacene) fluorophores, based on the use of photoremovable protecting groups (PRPGs) with high reduction potentials that serve as both a photosensitive unit and a fluorescence quencher via photoinduced electron transfer (PeT). 2,6-Dinitrobenzyl (DNB)-caged BODIPY was efficiently photoactivated, with activation ratios exceeding 600-fold in aqueous solutions. We then combined this photoactivatable fluorophore with a SNAP (mutant of O 6-alkylguanine DNA alkyltransferase) ligand to obtain a small-molecule-based optical highlighter for visualization of protein dynamics, using the well-established SNAP tag technology. As proof of concept, we demonstrate spatiotemporal imaging of the fusion protein of epidermal growth factor receptor (EGFR) with SNAP tag in living cells. We also demonstrate highlighting of cells of interest in live zebrafish embryos, using the fusion protein of histone 2A with SNAP tag.
- Kobayashi, Tomonori,Komatsu, Toru,Kamiya, Mako,Campos, Claudia,Gonzalez-Gaitan, Marcos,Terai, Takuya,Hanaoka, Kenjiro,Nagano, Tetsuo,Urano, Yasuteru
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supporting information; experimental part
p. 11153 - 11160
(2012/09/22)
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- Palladium-Catalyzed Synthesis of Indoles by Reductive N-Heteroannulation of 2-Nitrostyrenes
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A palladium-phosphine catalyzed reductive N-heteroannulation of 2-nitrostyrenes, in the presence of carbon monoxide, producing indoles has been developed. Indoles were obtained, in moderate to excellent yield, from substituted 2-nitrostyrenes having either electron-withdrawing (NO2 and CO2-Me) or electron-donating (Br, OH, Me, OMe, and OTf) substituents on the aromatic ring. Best results were obtained using palladium diacetate (6 mol percent) together with triphenylphosphine (24 mol percent) as the catalytic system, under 4 atm of carbon monoxide in acetonitrile at 70 °C. Other palladium(II) and palladium(0) complexes also catalyze the reaction.
- So?derberg, Bjo?rn C.,Shriver, James A.
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p. 5838 - 5845
(2007/10/03)
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