Nature Chem. Biol. doi:10.1038/nchembio.314 (2010)

Researchers and drug developers often use bacteria to churn out proteins in vast numbers, but the microbes are not equipped to create glycoproteins — proteins with sugar chains attached — of the kind that are useful to mammalian cells. Markus Aebi of the Swiss Federal Institute of Technology in Zurich, Lai-Xi Wang at the University of Maryland in Baltimore and their colleagues have modified the bacterium Escherichia coli to produce mammalian-style glycoproteins.

The microbes carry a set of genes from another bacterium, Campylobacter jejuni, that enable the E. coli to link sugar chains to the nitrogen atoms of certain amino acids in proteins. The authors engineered this pathway to generate the same protein–sugar linkage that mammalian cells do. After extracting the proteins, they added enzymes and synthesized sugars to trim and remodel the attached sugar chain, creating the desired glycoprotein.