This invention provides prokaryotic β1,4-N-acetylgalactosaminyl (GalNAc) transferases involved in synthesis of lipooligosaccharide (LOS). β1,4-GalNAc transferases are obtained from, for example, Campylobacter species, including C. jejuni. In additional embodiments, the invention provides nucleic acids that encode the β1,4-GalNAc transferases, as well as expression vectors and host cells for expressing the β1,4-GalNAc transferases.