Fishing Out Glycosyltransferases

Cells use glycosyltransferases biosynthetically to form glycosidic linkages between sugar “donor” and “acceptor” molecules, and chemists use them to synthesize new sugar-based biomolecules in the laboratory. To better understand sugar-based biosynthetic processes and to be able to make a wider variety of oligosaccharides in the lab, it is useful to know about as many glycosyltransferases as possible. But finding previously unknown glycosyltransferases in complex cell media has been a challenging task. Now, an array-based method—devised by Peng George Wang of Nankai University, in China; Milan Mrksich of Northwestern University; and coworkers—could make it easier to identify and characterize glycosyltransferases (Nat. Chem. Biol., DOI: 10.1038/nchembio.1022). In the technique, solutions of sugar donors and putative glycosyltransferases (produced by bacterial gene expression) are applied to self-assembled monolayers of sugar acceptors. Then linkage products, if any, are analyzed by mass spectrometry to detect new glycosyltransferases and their activity. The system enabled the researchers to identify and characterize four new glycosyltransferases. The researchers believe a similar array/MS strategy can be extended to the identification of other types of enzymes as well.