ChemCafé

Synthetic chemists use to perform their reactions in various pieces of glassware such as round-bottomed flasks, vials, Schlenk tubes of simple beakers. An article recently published in PNAS(1) reports synthetic chemistry performed in an unusual environment, as the authors present it, ‘in the physiologically relevant context of a mouse‘!

The team from University of California (UC) Berkeley, and the Lawrence Berkeley National Laboratory, led by Carolyn Bertozzi, adapted the methodology known as ‘click-chemistry‘ to the particular conditions required by ‘in vivo’ conditions. Indeed, the original ‘click’ procedures, developed by Barry Sharpless (2), involved the use of toxic copper catalysts. In their article, the authors use a copper-free click reaction to label glycans – sugars particularly abundant on the surface of cells, where they are active in cell activity signalling, as well as in response to infections – which are thought of as appealing target for molecular imaging inside living organisms.

The first step involved the injection of azide-containing sugar derivatives, which are known to metabolically label glycans with the azide function. Then, a purposedly designed molecule carrying a signalling unit as well as a function reactive towards azides, had to be injected. The click reaction proceeded and as a result, glycans could be labeled in vivo, which paves the way for future specific biomolecule labeling inside living organisms.

Click chemistry inside a mouse (reproduced from ref. 1)

References:
(1) Pamela V. Chang, Jennifer A. Prescher, Ellen M. Sletten, Jeremy M. Baskin, Isaac A. Miller, Nicholas J. Agard,
Anderson Lo, and Carolyn R. Bertozzi, “Copper-free click chemistry in living animals”, Proc. Natl. Acad. Sci. USA, published online before print January 14, 2010. doi:10.1073/pnas.0911116107

(2) H. C. Kolb, M. G. Finn and K. B. Sharpless “Click Chemistry: Diverse Chemical Function from a Few Good Reactions”, Angew. Chem., Int. Ed. 2001, 40 2004–2021. doi:10.1002/1521-3773(20010601)40:11<2004::AID-ANIE2004>3.0.CO;2-5

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