This invention provides prokaryotic .beta.1,4-N-acetylglucosaminyl (GalNAc) traosferases involved in synthesis of lipooligosaccharide (LOS). The .beta.1,4-GalNAc transferases can be obtained from, for example, Campylobacter species, including C. jejuni. In additional embodiments, the invention provides nucleic acids that encode the .beta.1,4-GaINAc transferases, as well as expression vectors and host cells for expressing the .beta.1,4-GalNAc transferases.