Present address: Building G08, School of Molecular Bioscience, University of Sydney, Camperdown, NSW 2006, Australia.
The Wzx translocases for Salmonella enterica O-antigen processing have unexpected serotype specificity
Article first published online: 12 APR 2012
© 2012 Blackwell Publishing Ltd
Volume 84, Issue 4, pages 620–630, May 2012
How to Cite
Hong, Y., Cunneen, M. M. and Reeves, P. R. (2012), The Wzx translocases for Salmonella enterica O-antigen processing have unexpected serotype specificity. Molecular Microbiology, 84: 620–630. doi: 10.1111/j.1365-2958.2012.08048.x
- Issue published online: 4 MAY 2012
- Article first published online: 12 APR 2012
- Accepted 20 March, 2012.
Most Gram-negative bacteria have an O antigen, a polysaccharide with many repeats of a short oligosaccharide that is a part of the lipopolysaccharide, the major lipid in the outer leaflet of the outer membrane. Lipopolysaccharide is variable with 46 forms in Salmonella enterica that underpin the serotyping scheme. Repeat units are assembled on a lipid carrier that is embedded in the cell membrane, and are then translocated by the Wzx translocase from the cytoplasmic face to the outer face of the cell membrane, followed by polymerization. The O antigen is then incorporated into lipopolysaccharide and exported to the outer membrane. The Wzx translocase is widely thought to be specific only for the first sugar of the repeat unit, despite extensive variation in both O antigens and Wzx translocases. However, we found for S. enterica groups B, D2 and E that Wzx translocation exhibits significant specificity for the repeat-unit structure, as variants with single sugar differences are translocated with lower efficiency and little long-chain O antigen is produced. It appears that Wzx translocases are specific for their O antigen for normal levels of translocation.