N-linked glycosylation in bacteria: an unexpected application.

Traditionally, glycoproteins have been considered the exclusive property of eukaryotes and archaea, but it is now evident that glycoproteins are found in all domains of life. In recent years N-linked glycosylation among some epsilon-proteobacteria has emerged as a new and exciting research area and represents a useful model to understand this complex process in simple, genetically tractable bacteria. Above all, the transfer of N-linked glycosylation systems to the work-horse bacterium, Escherichia coli, has enabled, for the first time, the production of recombinant glycoproteins. This has potentially provided the option for tailor-made glycoproteins and has opened up the field of glycoengineering, particularly with respect to the development of glycoconjugate vaccines.