Immuno-detection of the virulence determinant OmpX at the cell surface of Enterobacter cloacae

• Published in: FEMS microbiology letters 1998, Vol.158 (1), p.115-120
• Main Authors: de Kort, Gijs, van der Bent-Klootwijk, Paola, van de Klundert, Jos A.M
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Animals; Antibody Specificity; Bacterial Outer Membrane Proteins - analysis; Bacterial Outer Membrane Proteins - genetics; Bacterial Outer Membrane Proteins - immunology; Blotting, Western; Cell Membrane - chemistry; Cell Membrane - ultrastructure; Chromatography, High Pressure Liquid; Enterobacter cloacae - chemistry; Enterobacter cloacae - genetics; Enterobacter cloacae - pathogenicity; Epitopes - analysis; Escherichia coli - chemistry; Escherichia coli - genetics; Escherichia coli - immunology; Escherichia coli Proteins; Hydrolases; Immuno-gold labelling; Immunohistochemistry; Lipopolysaccharides - immunology; Microscopy, Immunoelectron; Molecular Sequence Data; OmpX; Outer membrane; Peptides - analysis; Peptides - chemical synthesis; Plasmids; Rabbits; Topology; Virulence
• ISSN: 0378-1097; 1574-6968
• DOI: 10.1016/S0378-1097(97)00510-7

A model for the topology of the Enterobacter cloacae outer membrane protein OmpX has been proposed, based on the primary sequence and on analogy to homologous proteins. According to this model the membrane embedded part of the protein consists of eight antiparallel β-strands. Four random coil loops are located at the bacterial surface and three β-turns at the periplasmic side of the membrane. Antibodies were raised against synthetic peptides representing five OmpX domains, four of which are putative peripheral and one located in the membrane. The accessibilities of OmpX to these antibodies were tested in intact cells by immuno-gold electron microscopy. This study showed that OmpX is indeed an outer membrane protein, the N-proximal loop of which forms an IgG-accessible epitope at the cell surface.