Effect of eliminase gene (elmA) deletion on heparosan production and shedding in Escherichia coli K5.

Escherichia coli K5 produces heparosan and sheds it into the growth medium in a temperature dependent manner. The shedding is believed to be controlled, at least in part, by enzyme action on the cell-associated capsular polysaccharide, heparosan. One candidate enzyme in such shedding is eliminase. The eliminase gene (elmA) was deleted from the genome of E. coli K5 and its effect on secreted and cell-associated heparosan was investigated. Deletion of the eliminase gene resulted in a significant reduction in heparosan shedding into the medium and heparosan content in the capsule of the cells, indicating its pivotal role in heparosan synthesis and shedding by E. coli K5.