Capsular Polysaccharide Export in Escherichia Coli: A Determination of the Role of the KpsD Protein in Export across the Outer-Membrane

The export of capsular polysaccharides in Gram negative bacteria represents a major challenge, requiring a large negatively charged molecule to be exported across two lipid bilayers. Currently our detailed understanding of this process is scant. <P>
This proposal will study the role of the KpsD protein in the export of group 2 capsular polysaccharides across the outer-membrane in Escherichia coli. The proposal has four aims. First to elucidate the topology of KpsD in the outer-membrane. Secondly to demonstrate the ability of KpsD to form pores in vitro and undertake a structure function analysis of KpsD. Thirdly to investigate interactions between KpsD and the peptidoglycan cell through which the exported polysaccharide molecule must traverse. Finally to understand the spatial localisation of capsular polysaccharide export at the poles of the cells.