- Azabicyclic vinyl sulfones for residue-specific dual protein labelling
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We have developed [2.2.1]azabicyclic vinyl sulfone reagents that simultaneously enable cysteine-selective protein modification and introduce a handle for further bioorthogonal ligation. The reaction is fast and selective for cysteine relative to other amino acids that have nucleophilic side-chains, and the formed products are stable in human plasma and are moderately resistant to retro Diels-Alder degradation reactions. A model biotinylated [2.2.1]azabicyclic vinyl sulfone reagent was shown to efficiently label two cysteine-tagged proteins, ubiquitin and C2Am, under mild conditions (1-5 equiv. of reagent in NaPi pH 7.0, room temperature, 30 min). The resulting thioether-linked conjugates were stable and retained the native activity of the proteins. Finally, the dienophile present in the azabicyclic moiety on a functionalised C2Am protein could be fluorescently labelled through an inverse electron demand Diels-Alder reaction in cells to allow selective apoptosis imaging. The combined advantages of directness, site-specificity and easy preparation mean [2.2.1]azabicyclic vinyl sulfones can be used for residue-specific dual protein labelling/construction strategies with minimal perturbation of native function based simply on the attachment of an [2.2.1]azabicyclic moiety to cysteine.
- Gil De Montes, Enrique,Jiménez-Moreno, Ester,Oliveira, Bruno L.,Navo, Claudio D.,Cal, Pedro M. S. D.,Jiménez-Osés, Gonzalo,Robina, Inmaculada,Moreno-Vargas, Antonio J.,Bernardes, Gon?alo J. L.
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p. 4515 - 4522
(2019/04/29)
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- Reactivity of 7-Azanorbornenes in Bioorthogonal Inverse Electron-Demand Diels–Alder Reactions
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In the preparation of multicomponent compounds, the accumulation of components through sequential click reactions is an attractive strategy. In this work we examined the reactivity of various N-substituted 7-azanorbornenes in inverse electron-demand Diels–Alder (iEDDA) reactions with tetrazines to explore the potential of 7-azanorbornenes as clickable hub molecules. The iEDDA reaction of 7-azanorbornene is expected to proceed faster when the nitrogen atom at the 7-position is substituted with an electron-donating substituent. Contrary to this expectation, the electron-donating alkyl-bearing derivative reacted much more slowly than those bearing electron-withdrawing acyl groups. The results of DFT calculations indicate that the reaction rates correlate well with an increase in sp2 character of the 7-nitrogen atoms: The ease of conversion of the more stable exo conformer into the more reactive endo conformer may lower the activation energy of the first rate-determining hetero-Diels–Alder step. Indeed, the reaction rates of N-acylated 7-azanorbornenes, which have a more planar nitrogen atom, were found superior to those of other derivatives and comparable to those of norbornenes. Finally, we successfully labeled a tetrazine on a protein surface by fluorophore-conjugated 7-azanorbornene in the presence of other proteins.
- Karaki, Fumika,Ohgane, Kenji,Imai, Hirotaka,Itoh, Kennosuke,Fujii, Hideaki
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p. 3815 - 3829
(2017/07/22)
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- Synthesis and spectroscopic characterisation of BODIPY based fluorescent off-on indicators with low affinity for calcium
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Two fluorescent off-on Ca2+ indicators based on APTRA (o-aminophenol-N,N-triacetic acid) as low-affinity ligand for Ca2+ and BODIPY (4,4-difluoro-4-bora-3a,4a-diaza-s-indacene) as a fluorophore were synthesized. The new BODIPY-APTRA
- Basaric, Nikola,Baruah, Mukulesh,Qin, Wenwu,Metten, Bert,Smet, Mario,Dehaen, Wim,Boens, Noel
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p. 2755 - 2761
(2007/10/03)
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- Addition of γ-methoxy allylsulfonyl anions to cyclopentenyl phenyl sulfones. A facile synthesis of β-cyclopentenyl-substituted dienones and trienones
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γ-Methoxy allylsulfonyl anions undergo smooth conjugate addition to mono- and bicyclic cyclopentyl sulfones. Hydrolysis of the intermediate adducts affords δ-sulfonyl-substituted enones which may be eliminated to dienyl ketones. The mechanism of this reaction is shown to involve the intermediacy of spiro-fused cyclopropyl sulfones conjugated to an enol ether moiety. Exploration of the scope and limitations of this procedure demonstrates the potential for triply-convergent synthesis of tricyclic dienones via cyclization of a trienyl ketone.
- Jin, Zhendong,Fuchs
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p. 3022 - 3028
(2007/10/02)
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- Synthesis and Chemistry of N-Oxygenated Pyrroles: Crystal and Molecular Structure of a Highly Stable N-Hydroxypyrrole 18-Crown Ether Hydrate
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N-Oxygenated succimides 5-8, 13, and 14, N-oxydithiosuccinimides 10 and 11, and N-oxygenated pyrroles 12, 30a,e, 38, and 39 were synthesized as possible precursors of a pyrrole nitroxide crown ether.N-Methoxypyrrole dithiocrown ethers 21 and 23-27 were pr
- Keana, John F. W.,Heo, Gwi Suk,Mann, Jeffry S.,Nice, Faith L. Van,Lex, Laszlo,et al.
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p. 2268 - 2274
(2007/10/02)
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