For the past several years, Bertozzi has been developing new techniques for studying glycans. Even though glycans are ubiquitous on the surfaces of most cells and play a critical role in intercellular communications, methods for studying them have lagged behind other biomolecules.
Glycans mediate a variety of cell surface recognition events such as bacterial and viral binding to host cells and leukocyte adhesion during an inflammatory response, said Bertozzi. In addition to their cell surface roles, glycans can regulate many intracellular processes, including trafficking of proteins to the lysosome and transcription and translation.
There is great scientific interest in monitoring the dynamics of glycans as they move about within cells and on the cell surface, but the means to tag glycans with imaging probes has been lacking, thereby prohibiting such studies. Bertozzi and her coworkers had previously shown that glycans can be metabolically labeled with azides, permitting their chemical tagging with imaging probes through click chemistry, but the cytotoxicity of the click reaction would not allow dynamic imaging of live cells.
To apply click chemistry to glycans, Bertozzi and her colleagues designed a new reagent called difluorinated cyclooctyne or DIFO, that reacts with azides rapidly at physiological temperatures without the need for a toxic catalyst.
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|Contact: Lynn Yarris|
DOE/Lawrence Berkeley National Laboratory