Analysis of the Pentose Efflux Transporters in Escherichia Coli

Escherichia coli expresses proteins that not only pump sugars into the cell but also pump them out. In other words, E. coli expresses a number of efflux transporters that pump sugars out of the cell. Little is known about these sugar efflux transporters or why E. coli has them.

In this work, we investigated the role of efflux transporters on pentose metabolism. We show that E. coli expresses a number of proteins that pump pentose sugars such as arabinose and xylose out of the cell. Using genetic approaches, we demonstrate that by either deleting or overexpressing these efflux transporters we can respectively increase or decrease the uptake of pentose sugars. We have also explored the role that these efflux transporters play in removing toxic compounds and metabolic byproducts from the cell. Collectively, these results demonstrate that efflux transporters play an important role in the metabolism of pentose transporters. They also may identify a new target for metabolic engineering.