Nucleotide sequence and mutational analysis of the gene encoding KpsD, a periplasmic protein involved in transport of polysialic acid in Escherichia coli K1

Analysis of the mutants in Kps gene cluster of E. coli K1 reveals that transport defects affect synthetic activities, as seen by the expression of polysialic acid (PSA), due to the accumulation of protein K in the outer membrane. Kps gene products have the ability to transport a range of acidic polysaccharides due to protein-polysaccharide interaction. KpsD is the periplasmic binding component of the PSA transport system that transport the polymer to the outer membrane.