Glycosylation of the Enterobacter cloacae outer membrane protein OmpX in eukaryotic cells

The topological model of the Enterobacter cloacae outer membrane protein Om pX showed three putative glycosylation sites. When OmpX was expressed in ba cteria that were cultured under aerated conditions, no glycosylation was ob served. The coupling of carbohydrate chains to the ompX gene product was al so investigated in the eukaryotic baculovirus expression system. For this p urpose, a recombinant ompX gene-containing baculovirus was made. Infection of insect cells with this recombinant virus resulted in the production of s ufficient amounts of OmpX to study glycosylation. In this system, all poten tial N-glycosylation sites of OmpX were utilized. Furthermore, it became cl ear that glycosylated OmpX was retained in the insect cells and was not sec reted in the medium. Given the fact that OmpX plays a role in the invasion of E. cloacae in rabbit enterocytes, glycosylation of this protein occurrin g only under specific conditions may be involved in this process. (C) 1999 Federation of European Microbiological Societies. Published by Elsevier Sci ence B.V. All rights reserved.