Involved in extracellular lipooligosaccharide (LOS) biosynthesis and virulence expression. Involved in the synthesis of the oligosaccharide moiety of the LOS molecule by adding GalNAc. Between 2 and 7 copies of the SINQ repeats are to be found in different strains; these are thought to serve to generate phase-variable expression of this gene. The (SINQ)n peptide may form a random coiled structure that permits appropriate interactions between the N- and C-terminal domains of the protein. Belongs to the glycosyltransferase 25 family. It is uncertain whether Met-1 or Met-11 is the initiator.