The identification of a new family of sugar efflux pumps in Escherichia coli.
Using a functional cloning strategy with an Escherichia coli genomic plasmid library, we have identified a new family of sugar efflux proteins with three highly homologous members in the E. coli genome. In addition, two open reading frames, one present in Yersinia pestis and the other in Deinococcus radiodurans, appear to encode closely related proteins. An in vitro transport assay using inside-out membrane vesicles prepared from overproducing strains was used to demonstrate that members of this new family can efflux [14C]-lactose. As sugar efflux phenomena have been reported previously in several bacterial species including E. coli, the identification of a new family of sugar efflux proteins may help to reveal the physiological role of sugar efflux in metabolism. It is proposed that the E. coli members of this family, whose functions were previously unknown, be given the gene family designation SET for sugar efflux transporter.
Liu
J Y
JY
Infectious Diseases Department, Parke-Davis Pharmaceutical Research, Division of Warner-Lambert Company, Ann Arbor, MI 48106-1047, USA.
Miller
P F
PF
Gosink
M
M
Olson
E R
ER
D017920:Antiporters / Q000378:metabolism; D001426:Bacterial Proteins / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004926:Escherichia coli / Q000378:metabolism*; D029968:Escherichia coli Proteins; D015698:Genomic Library; D015151:Immunoblotting; D007544:Isopropyl Thiogalactoside / Q000494:pharmacology; D007785:Lactose / Q000378:metabolism; D009004:Monosaccharide Transport Proteins / Q000235:genetics / Q000378:metabolism; D005810:Multigene Family; D010957:Plasmids; D013997:Time Factors; D015010:Yersinia pestis / Q000235:genetics; D001616:beta-Galactosidase / Q000378:metabolism
D017920:Antiporters; D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; D009004:Monosaccharide Transport Proteins; C119765:setA protein, E coli; C119764:setB protein, E coli; C119763:setC protein, E coli; C079051:tetA protein, Bacteria; D007544:Isopropyl Thiogalactoside; D001616:beta-Galactosidase; D007785:Lactose