Mediates phase variation of the LOS 6A2 and 12D9 epitopes. Phase variation of H.influenza LOS epitopes expressed by LicA is determined by a translational switch. Between 2 and 19 copies of the INQS repeats are to be found in different strains; these are thought to serve to generate phase-variable expression of this gene. There is spontaneous, high frequency switching between three discrete levels of expression (++++, +, -) of oligosaccharide epitopes. Lipooligosaccharide (LOS) is a glycolipid that is a necessary component and antigenic determinant of the outer membrane and has been shown to be an important factor in the host-parasite interaction in a number of Gram-negative species. H.influenzae is able to display an extensive repertoire of different surface configurations through variability of its LOS. Belongs to the peptidase S49 family.